2021 Vol. 42 No. 21
2021, 42(21): 1-7.
DOI: 10.13386/j.issn1002-0306.2021060130
Cited By
Abstract：
Staphylococcus aureus is one of the most important foodborne pathogens. Rapid detection is of vital importance for the prevention and control of outbreaks caused by this bacterial pathogen. Biological recognition elements are the core of rapid detection. As the emerging biological recognition element, nucleic acid aptamers are easy to be prepared and modified, and have high affinity and specificity that can be combined with targets well, which have great potential and advantages when applied in the detection of foodborne pathogens. For the sake of broadening research ideas on development and application of detection methods for Staphylococcus aureus, aptamer screening technologies and detection methods based on aptamers are reviewed in this article.
Staphylococcus aureus is one of the most important foodborne pathogens. Rapid detection is of vital importance for the prevention and control of outbreaks caused by this bacterial pathogen. Biological recognition elements are the core of rapid detection. As the emerging biological recognition element, nucleic acid aptamers are easy to be prepared and modified, and have high affinity and specificity that can be combined with targets well, which have great potential and advantages when applied in the detection of foodborne pathogens. For the sake of broadening research ideas on development and application of detection methods for Staphylococcus aureus, aptamer screening technologies and detection methods based on aptamers are reviewed in this article.
2021, 42(21): 8-16.
DOI: 10.13386/j.issn1002-0306.2021030361
Abstract：
Baojing Huangjincha was used as raw material and processed according to congou black tea technology, used metabolomics-based liquid-mass spectrometry (LC-MS/MS) to detect tea samples during the fermentation process, and analyzed the dynamic changes of metabolites during the fermentation process of congou black tea. The results showed that during the fermentation process, the metabolites in tea showed regular dynamic changes. A total of 493 different metabolites were screened in the study, moreover, the change trend of these different metabolites can be divided into two stages, namely the early stage of fermentation and the later stage of fermentation, taking the 2 h fermentation as the node. In the early stage of fermentation, the metabolites were change significantly, and the material metabolism was active, while the differential metabolites in the later stage of fermentation were significantly less than that in the early stage of fermentation, and the material metabolism was weakened. Analysis of the identified 90 differential metabolites showed that the astringent metabolites were down-regulated during the fermentation of black tea, and the soluble sugars and theaflavins were sweetened and refreshing metabolites were significantly up-regulated. This experiment provides an important reference for exploring the mechanism of substance metabolism regulation in the fermentation process of congou black tea.
Baojing Huangjincha was used as raw material and processed according to congou black tea technology, used metabolomics-based liquid-mass spectrometry (LC-MS/MS) to detect tea samples during the fermentation process, and analyzed the dynamic changes of metabolites during the fermentation process of congou black tea. The results showed that during the fermentation process, the metabolites in tea showed regular dynamic changes. A total of 493 different metabolites were screened in the study, moreover, the change trend of these different metabolites can be divided into two stages, namely the early stage of fermentation and the later stage of fermentation, taking the 2 h fermentation as the node. In the early stage of fermentation, the metabolites were change significantly, and the material metabolism was active, while the differential metabolites in the later stage of fermentation were significantly less than that in the early stage of fermentation, and the material metabolism was weakened. Analysis of the identified 90 differential metabolites showed that the astringent metabolites were down-regulated during the fermentation of black tea, and the soluble sugars and theaflavins were sweetened and refreshing metabolites were significantly up-regulated. This experiment provides an important reference for exploring the mechanism of substance metabolism regulation in the fermentation process of congou black tea.
2021, 42(21): 17-24.
DOI: 10.13386/j.issn1002-0306.2020100058
Abstract：
Chitosan modified montmorillonite was prepared by coprecipitation method and used to adsorb phenolic acids in sucrose solution. It was characterized by SEM, FT-IR, XPS and BET. The results showed that chitosan was successfully loaded on the surface of montmorillonite to prepare chitosan modified montmorillonite. The isoelectric point of modified montmorillonite was 7.84, and gallic acid in sucrose solution was mainly adsorbed by electrostatic force and amine group. The results of adsorption test showed that the modified montmorillonite had better adsorption performance for gallic acid. The optimal pH of chitosan modified montmorillonite for gallic acid adsorption in sucrose solution was 7.0, and the equilibrium time was 600 min. The adsorption process of chitosan modified montmorillonite for gallic acid was more in line with Freundlich model and quasi second order adsorption kinetic equation. The adsorption process was mainly multimolecular layer adsorption and chemical adsorption, and the saturated adsorption capacity reached 58.82 mg/g. Chitosan modified montmorillonite exhibited a good regeneration performance and good adsorption effect on phenolic acids in sucrose solution. It performed a promising clarifier for sugar.
Chitosan modified montmorillonite was prepared by coprecipitation method and used to adsorb phenolic acids in sucrose solution. It was characterized by SEM, FT-IR, XPS and BET. The results showed that chitosan was successfully loaded on the surface of montmorillonite to prepare chitosan modified montmorillonite. The isoelectric point of modified montmorillonite was 7.84, and gallic acid in sucrose solution was mainly adsorbed by electrostatic force and amine group. The results of adsorption test showed that the modified montmorillonite had better adsorption performance for gallic acid. The optimal pH of chitosan modified montmorillonite for gallic acid adsorption in sucrose solution was 7.0, and the equilibrium time was 600 min. The adsorption process of chitosan modified montmorillonite for gallic acid was more in line with Freundlich model and quasi second order adsorption kinetic equation. The adsorption process was mainly multimolecular layer adsorption and chemical adsorption, and the saturated adsorption capacity reached 58.82 mg/g. Chitosan modified montmorillonite exhibited a good regeneration performance and good adsorption effect on phenolic acids in sucrose solution. It performed a promising clarifier for sugar.
2021, 42(21): 25-32.
DOI: 10.13386/j.issn1002-0306.2021010001
Abstract：
To obtain the best brewing technology of nectar wine and promote its industrialization. In this paper, the initial sugar content, the type of yeast, the addition amount of yeast and the fermentation temperature on sensory evaluation of nectar wine were measured by single factor experiment to determine the best factor combination. The nutritional composition, volatile composition contentand and aromatic composition of the optimized nectar wine were determined and analyzed. The results indicated that the optimal fermentation process parameters of nectar wine were as follows: the initial sugar degree was 22 °Brix, high active wine dry yeast was inoculated, the amount of yeast addition was 0.4 g/L, and the nectar wine got the best quality after 14 days of fermentation at 15 ℃. In the optimized fermentation process conditions, the indicators were as follows: glucose 20.0 g/L, fructose 76.6 g/L, sucrose 0 g/L, residual sugar content 15 °Brix, alcohol content 12.5% vol, malic acid 0.700 g/L, oxalic acid 0.049 g/L, total amount of 16 amino acids 32 mg/100 mL, which were phenylalanine, alanine, methionine, proline, glycine, glutamic acid, arginine, lysine, tyrosine, leucine, serine, threonine, aspartic acid, valerine, isoleucine and histidine, including the content of isoleucine, asparagine, phenylalanine and glutamic acid, giving the nectar wine a rich flavor. The 16 volatile compounds were including ethanol, ethyl acetate, isobutanol, isoamyl alcohol, 2-methyl butanol, phenylethyl alcohol, 1,2,4,5-tetramethylbenzene, naphthalene, 2,5-dimethylbenzaldehyde, phenyethyl acetate, ethyl caprate, 2,4-ditertbutylphenol, ethyl dodecanoate, ethyl tetradecanoate, ethyl 9-hexadecenoate, and ethyl palmitate. The highest concentrations of ethanol and phenylethanol were 50.13% and 38.41%, respectively, which were the main sources of nectar wine flavor.
To obtain the best brewing technology of nectar wine and promote its industrialization. In this paper, the initial sugar content, the type of yeast, the addition amount of yeast and the fermentation temperature on sensory evaluation of nectar wine were measured by single factor experiment to determine the best factor combination. The nutritional composition, volatile composition contentand and aromatic composition of the optimized nectar wine were determined and analyzed. The results indicated that the optimal fermentation process parameters of nectar wine were as follows: the initial sugar degree was 22 °Brix, high active wine dry yeast was inoculated, the amount of yeast addition was 0.4 g/L, and the nectar wine got the best quality after 14 days of fermentation at 15 ℃. In the optimized fermentation process conditions, the indicators were as follows: glucose 20.0 g/L, fructose 76.6 g/L, sucrose 0 g/L, residual sugar content 15 °Brix, alcohol content 12.5% vol, malic acid 0.700 g/L, oxalic acid 0.049 g/L, total amount of 16 amino acids 32 mg/100 mL, which were phenylalanine, alanine, methionine, proline, glycine, glutamic acid, arginine, lysine, tyrosine, leucine, serine, threonine, aspartic acid, valerine, isoleucine and histidine, including the content of isoleucine, asparagine, phenylalanine and glutamic acid, giving the nectar wine a rich flavor. The 16 volatile compounds were including ethanol, ethyl acetate, isobutanol, isoamyl alcohol, 2-methyl butanol, phenylethyl alcohol, 1,2,4,5-tetramethylbenzene, naphthalene, 2,5-dimethylbenzaldehyde, phenyethyl acetate, ethyl caprate, 2,4-ditertbutylphenol, ethyl dodecanoate, ethyl tetradecanoate, ethyl 9-hexadecenoate, and ethyl palmitate. The highest concentrations of ethanol and phenylethanol were 50.13% and 38.41%, respectively, which were the main sources of nectar wine flavor.
2021, 42(21): 33-40.
DOI: 10.13386/j.issn1002-0306.2021010027
Abstract：
In order to select the best frame modes of passion fruit, five typical frames were selected in this study: hedge single-layer frame (FBSD), hedge double-layer frame (FBSS), wide-narrow row single-layer frame (KZHD), wide-narrow row double-layer frame (KZHS), flat shed vertical frame (PPJ). Through the analysis and comparison of the difference of yield and nutritional components of passion fruit, and the multivariate statistical analysis method (PCA) was used for principal component analysis and comprehensive evaluation. The results showed that the yield of passion fruit was the highest under FBSS and KZHS, and the yield per mu was 1156.48 kg and 1035.13 kg, respectively. There was no significant difference in the appearance quality of passion fruit among different frame modes, and the sugar-acid ratio of passion fruit in FBSD, FBSS, KZHD, KZHS and PPJ were 2.89, 2.45, 2.72, 2.46 and 2.26, respectively. The contents of total amino acid (TAA), essential amino acid (EAA) and flavor amino acid (FAA) in FBSD were the highest, which were 1366.60, 369.64 and 799.50 mg/100 g, respectively. The content of essential amino acids accounted for 27.05% of the total amino acids. The contents of total amino acid (TAA) and flavor amino acid (FAA) in FBSS were the lowest, which were 948.54 and 549.68 mg/100 g, respectively, and the content of essential amino acids was 29.61%. The contents of sweet amino acids and acidity amino acids in the five frame modes accounted for 37.09%~41.08% and 58.92%~62.91% of the flavor amino acids, respectively. Four principal component factors were extracted from 39 indexes by PCA, and the contribution rate of cumulative variance was 100.0%. According to the contribution rate of variance of four principal components, a comprehensive evaluation model was established to calculate the comprehensive total scores of different frame modes, and the order was FBSD (2.097)>KZHD (1.836)>FBSS (1.589)>KZHS (1.476)>PPJ (1.229). It showed that among the five frame modes, FBSD was the best frame modes in the process of passion fruit planting. This study can lay a theoretical foundation for the popularization and application of passion fruit.
In order to select the best frame modes of passion fruit, five typical frames were selected in this study: hedge single-layer frame (FBSD), hedge double-layer frame (FBSS), wide-narrow row single-layer frame (KZHD), wide-narrow row double-layer frame (KZHS), flat shed vertical frame (PPJ). Through the analysis and comparison of the difference of yield and nutritional components of passion fruit, and the multivariate statistical analysis method (PCA) was used for principal component analysis and comprehensive evaluation. The results showed that the yield of passion fruit was the highest under FBSS and KZHS, and the yield per mu was 1156.48 kg and 1035.13 kg, respectively. There was no significant difference in the appearance quality of passion fruit among different frame modes, and the sugar-acid ratio of passion fruit in FBSD, FBSS, KZHD, KZHS and PPJ were 2.89, 2.45, 2.72, 2.46 and 2.26, respectively. The contents of total amino acid (TAA), essential amino acid (EAA) and flavor amino acid (FAA) in FBSD were the highest, which were 1366.60, 369.64 and 799.50 mg/100 g, respectively. The content of essential amino acids accounted for 27.05% of the total amino acids. The contents of total amino acid (TAA) and flavor amino acid (FAA) in FBSS were the lowest, which were 948.54 and 549.68 mg/100 g, respectively, and the content of essential amino acids was 29.61%. The contents of sweet amino acids and acidity amino acids in the five frame modes accounted for 37.09%~41.08% and 58.92%~62.91% of the flavor amino acids, respectively. Four principal component factors were extracted from 39 indexes by PCA, and the contribution rate of cumulative variance was 100.0%. According to the contribution rate of variance of four principal components, a comprehensive evaluation model was established to calculate the comprehensive total scores of different frame modes, and the order was FBSD (2.097)>KZHD (1.836)>FBSS (1.589)>KZHS (1.476)>PPJ (1.229). It showed that among the five frame modes, FBSD was the best frame modes in the process of passion fruit planting. This study can lay a theoretical foundation for the popularization and application of passion fruit.
Abstract：
As one of the main oil-bearing crops in China, peanuts are susceptible to the contamination of Aspergillus flavus during processing and storage, which results in the loss of commercial values. Hence, it is crucial to investigate the signaling molecules during the early stage of contamination in order to monitor and control the spread of A. flavus in peanuts. In this study, Gas chromatography–ion mobility spectrometry (GC-IMS) was used to analyze the volatile organic compounds (VOCs) during the invasion of A. flavus in peanuts. A total of 53 compounds were detected, including 34 confirmed monomers and dimers. The other 19 compounds were yet to be qualitatively determined. The results showed that the organic compounds produced by A. flavus varied significantly in the different growth stages. The fingerprint spectrum demonstrated the changing patterns and relative concentrations of the volatile organic compounds as the contamination progressed, and the characteristic peaks could be used to quantify the level of contamination at the early stages. The volatile organic compounds were also analyzed with heat map clustering and principal component analysis. Significant differences were observed among the volatile organic compounds at different stages of contamination. The study determined that caproic acid, 2, 3-butanedione, 2-hexen-1-ol-M, pentan-1-ol-M and hexanal could be used as the signaling molecules during the early stages of A. flavus contamination. The results of this study provide an effective marker for the development of early warning monitoring system for peanut mildew degree under storage conditions.
As one of the main oil-bearing crops in China, peanuts are susceptible to the contamination of Aspergillus flavus during processing and storage, which results in the loss of commercial values. Hence, it is crucial to investigate the signaling molecules during the early stage of contamination in order to monitor and control the spread of A. flavus in peanuts. In this study, Gas chromatography–ion mobility spectrometry (GC-IMS) was used to analyze the volatile organic compounds (VOCs) during the invasion of A. flavus in peanuts. A total of 53 compounds were detected, including 34 confirmed monomers and dimers. The other 19 compounds were yet to be qualitatively determined. The results showed that the organic compounds produced by A. flavus varied significantly in the different growth stages. The fingerprint spectrum demonstrated the changing patterns and relative concentrations of the volatile organic compounds as the contamination progressed, and the characteristic peaks could be used to quantify the level of contamination at the early stages. The volatile organic compounds were also analyzed with heat map clustering and principal component analysis. Significant differences were observed among the volatile organic compounds at different stages of contamination. The study determined that caproic acid, 2, 3-butanedione, 2-hexen-1-ol-M, pentan-1-ol-M and hexanal could be used as the signaling molecules during the early stages of A. flavus contamination. The results of this study provide an effective marker for the development of early warning monitoring system for peanut mildew degree under storage conditions.
Abstract：
In order to clarify the characteristics of the volatilecompounds of the new apple varieties, further popularize the new varieties. In this study, the newly selected ‘Ruixue’ and ‘Ruixianghong’ apples and their parents ‘Pink Lady’ and ‘Fuji’ were used as the materials. The headspace solid-phase micro extraction method combined with gas chromatography-mass spectrometry was used to detect the aroma compounds of four apple fruits, and the differences in the types, contents and characteristic aroma values of volatilecompounds were studied and analyzed. The results showed that a total of 58 volatilecompounds and 16 characteristic aroma compounds were detected and analyzed from 4 apple varieties. Among them, ‘Ruixue’ had 3 unique volatilecompounds and 10 characteristic volatilecompounds, and ‘Ruixianghong’ had 7 unique volatilecompounds and 13 kinds of characteristic volatilecompounds. Among the four apple varieties, the new variety ‘Ruixianghong’ had the most types of volatilecompounds and the highest content of volatilecompounds. The number of characteristic volatilecompounds of the two new varieties of ‘Ruixue’ and ‘Ruixianghong’ was higher than that of their parents. The characteristic volatilecompounds of (Z)-2-heptenal, hexanal and nonanal in ‘Ruixue’ were higher among the 4 varieties. The characteristic volatilecompounds of esters such as hexyl acetate, hexyl propionate, hexyl butyrate and hexyl 2-methylbutyrate in ‘Ruixianghong’ were the highest. The difference of these characteristic volatilecompounds may be an important reason for the unique aroma of the two new varieties.
In order to clarify the characteristics of the volatilecompounds of the new apple varieties, further popularize the new varieties. In this study, the newly selected ‘Ruixue’ and ‘Ruixianghong’ apples and their parents ‘Pink Lady’ and ‘Fuji’ were used as the materials. The headspace solid-phase micro extraction method combined with gas chromatography-mass spectrometry was used to detect the aroma compounds of four apple fruits, and the differences in the types, contents and characteristic aroma values of volatilecompounds were studied and analyzed. The results showed that a total of 58 volatilecompounds and 16 characteristic aroma compounds were detected and analyzed from 4 apple varieties. Among them, ‘Ruixue’ had 3 unique volatilecompounds and 10 characteristic volatilecompounds, and ‘Ruixianghong’ had 7 unique volatilecompounds and 13 kinds of characteristic volatilecompounds. Among the four apple varieties, the new variety ‘Ruixianghong’ had the most types of volatilecompounds and the highest content of volatilecompounds. The number of characteristic volatilecompounds of the two new varieties of ‘Ruixue’ and ‘Ruixianghong’ was higher than that of their parents. The characteristic volatilecompounds of (Z)-2-heptenal, hexanal and nonanal in ‘Ruixue’ were higher among the 4 varieties. The characteristic volatilecompounds of esters such as hexyl acetate, hexyl propionate, hexyl butyrate and hexyl 2-methylbutyrate in ‘Ruixianghong’ were the highest. The difference of these characteristic volatilecompounds may be an important reason for the unique aroma of the two new varieties.
2021, 42(21): 57-64.
DOI: 10.13386/j.issn1002-0306.2021010052
Abstract：
The pre-gelatinization of mungbeanstarch is a key processing procedure that distinguishes the starch-meat sausage from other smoked sausages. Therefore, the temperature of the pregelatinized starch is very important to the quality of the product. In this study, mung bean starch was pre-gelatinized with hot water at 75, 85 and 95 ℃ to prepare starch-meat sausages. The effect of different pre-gelatinization temperature on product quality and degree ofstarch gelatinization (DSG) was discussed. The results showed that with the increase of the pregelatinized starch temperature, the DSG and emulsion stability of starch-meat sausages increased significantly (P<0.05), the cooking loss was significantly reduced (P<0.05), and a lot of free water changed to immobile water. At the same time, with the increase of the pre-gelatinization temperature, the hardness, resilience, springiness, breaking force, chewiness, tightness and lightness value (L*) of the starch-meat sausages increased significantly (P<0.05), which promoted the formation of final product quality. The overall acceptability score reached the highest at 95 ℃ for pregelatinized starch (P<0.05). In addition, the results of the hierarchical cluster analysis (HCA) showed that the pre-gelatinization temperature of 95 ℃ had an up-regulated effect on the quality characteristics of starch-meat sausages. Insummary, 95 ℃ was the best pregelatinized starch temperature to improve the quality of starch-meat sausages.
The pre-gelatinization of mungbeanstarch is a key processing procedure that distinguishes the starch-meat sausage from other smoked sausages. Therefore, the temperature of the pregelatinized starch is very important to the quality of the product. In this study, mung bean starch was pre-gelatinized with hot water at 75, 85 and 95 ℃ to prepare starch-meat sausages. The effect of different pre-gelatinization temperature on product quality and degree ofstarch gelatinization (DSG) was discussed. The results showed that with the increase of the pregelatinized starch temperature, the DSG and emulsion stability of starch-meat sausages increased significantly (P<0.05), the cooking loss was significantly reduced (P<0.05), and a lot of free water changed to immobile water. At the same time, with the increase of the pre-gelatinization temperature, the hardness, resilience, springiness, breaking force, chewiness, tightness and lightness value (L*) of the starch-meat sausages increased significantly (P<0.05), which promoted the formation of final product quality. The overall acceptability score reached the highest at 95 ℃ for pregelatinized starch (P<0.05). In addition, the results of the hierarchical cluster analysis (HCA) showed that the pre-gelatinization temperature of 95 ℃ had an up-regulated effect on the quality characteristics of starch-meat sausages. Insummary, 95 ℃ was the best pregelatinized starch temperature to improve the quality of starch-meat sausages.
Abstract：
To investigate the effect of the polymerization degree of amylopectin on the physical and chemical properties of amylopectin-lipid complexes, the physical and chemical properties of five complexes (M1ZY, M2ZY, M3ZY, M4ZY and M5ZY) formed by jackfruit seed amylopectin (JFSA) with different polymerization degree and lauric acid were measured. The correlation between the gelatinization characteristic parameters, the weight-average polymerization degree (DPw) and the complex indexes (CI) of the five compounds were also analyzed. The results showed that the complex indexes of complexes were significantly increased (P<0.05) from 23.27% (M1ZY) up to 35.95% (M5ZY) with the increase of degree of amylopectin polymerization. The degree of syneresis, water solubility, oil solubility, swelling power and solubility of these five compounds were obviously increased. The gelatinization characteristic parameter values of the five compounds were significantly different. With the increase of amylopectin polymerization degree, the peak viscosity (PV), trough viscosity (TV) and final viscosity of the five compounds increased. However, the breakdown (BkD) and setback value (StB) decreased. The results of Pearson correlation analysis showed that the DPw of amylopectin was significantly positively correlated with the TV and CI of the complex (r=0.887, 0.949; P<0.05). The degree of amylopectin polymerization was an important factor affecting the physical and chemical properties of JFSA-lauric acid complexes.
To investigate the effect of the polymerization degree of amylopectin on the physical and chemical properties of amylopectin-lipid complexes, the physical and chemical properties of five complexes (M1ZY, M2ZY, M3ZY, M4ZY and M5ZY) formed by jackfruit seed amylopectin (JFSA) with different polymerization degree and lauric acid were measured. The correlation between the gelatinization characteristic parameters, the weight-average polymerization degree (DPw) and the complex indexes (CI) of the five compounds were also analyzed. The results showed that the complex indexes of complexes were significantly increased (P<0.05) from 23.27% (M1ZY) up to 35.95% (M5ZY) with the increase of degree of amylopectin polymerization. The degree of syneresis, water solubility, oil solubility, swelling power and solubility of these five compounds were obviously increased. The gelatinization characteristic parameter values of the five compounds were significantly different. With the increase of amylopectin polymerization degree, the peak viscosity (PV), trough viscosity (TV) and final viscosity of the five compounds increased. However, the breakdown (BkD) and setback value (StB) decreased. The results of Pearson correlation analysis showed that the DPw of amylopectin was significantly positively correlated with the TV and CI of the complex (r=0.887, 0.949; P<0.05). The degree of amylopectin polymerization was an important factor affecting the physical and chemical properties of JFSA-lauric acid complexes.
Abstract：
In order to examine the variation of volatile components of Eucommia ulmoides leaves Fu Brick Tea during processing, Gas Chromatography-Ion Mobility Spectroscopy (GC-IMS) was employed. The volatile compounds fingerprints of Eucommia ulmoides leaves Fu Brick Tea were plotted using Gallery Plot software. The differences between the samples from the six stages during processing and principal component analysis were assessed, respectively. The results showed that a total of 70 volatile compounds were detected in each sample of the six stages, including raw material screening, piling fermentation, steam and forming stage (the 0th day of flowering), the 8th day, the 25th day of flowering and the 1st year of aging stage. Among these compounds, qualitative analysis of 51 kinds of components were determined, including aldehydes, ketones, alcohols, esters, pyrazines, acids, terpenes, furans, ethers and sulfur compounds. PCA analysis showed that PC1 was 47%, PC2 was 27%, and the cumulative contribution rate was 74%, which was better reflected the influencing factors of the differences of volatile components among different tea samples. The tea samples at different stages were separated on the PCA chart, indicating that there were differences in the volatile components contents of tea samples at different stages in the processing. The relative contents of several kinds of pyrazines, aldehydes and ketones with grass flavor and earthy aroma in tea samples gradually decreased with the processing, while the relative contents of alcohols, aldehydes and esters with medicinal aroma, fruity aroma and mellow aroma gradually increased. Finally, the medicinal, fruity and fungus aroma of Eucommia ulmoides leaves Fu Brick Tea was formed. Moreover, the relative contents of 2-ethyl-3, 5-dimethylpyrazine dimer in the pile fermentation samples, 2, 4-heptadienal and 3-methylthiopropanal in the flowering stage samples, and 5-methylfurfural, butyl acrylate monomer, butyl acrylate dimer, furfural dimer, 2, 3-butanediol in the aging stage samples were higher than compared to other stages. Therefore, these compounds might be the potential indicators of the assessment of the piling fermentation, flowering and aging stage of Eucommia ulmoides leaves Fu brick tea, thus providing a tool for the regular monitoring of aroma components on the manufacturing process of Eucommia ulmoides leaves Fu brick tea.
In order to examine the variation of volatile components of Eucommia ulmoides leaves Fu Brick Tea during processing, Gas Chromatography-Ion Mobility Spectroscopy (GC-IMS) was employed. The volatile compounds fingerprints of Eucommia ulmoides leaves Fu Brick Tea were plotted using Gallery Plot software. The differences between the samples from the six stages during processing and principal component analysis were assessed, respectively. The results showed that a total of 70 volatile compounds were detected in each sample of the six stages, including raw material screening, piling fermentation, steam and forming stage (the 0th day of flowering), the 8th day, the 25th day of flowering and the 1st year of aging stage. Among these compounds, qualitative analysis of 51 kinds of components were determined, including aldehydes, ketones, alcohols, esters, pyrazines, acids, terpenes, furans, ethers and sulfur compounds. PCA analysis showed that PC1 was 47%, PC2 was 27%, and the cumulative contribution rate was 74%, which was better reflected the influencing factors of the differences of volatile components among different tea samples. The tea samples at different stages were separated on the PCA chart, indicating that there were differences in the volatile components contents of tea samples at different stages in the processing. The relative contents of several kinds of pyrazines, aldehydes and ketones with grass flavor and earthy aroma in tea samples gradually decreased with the processing, while the relative contents of alcohols, aldehydes and esters with medicinal aroma, fruity aroma and mellow aroma gradually increased. Finally, the medicinal, fruity and fungus aroma of Eucommia ulmoides leaves Fu Brick Tea was formed. Moreover, the relative contents of 2-ethyl-3, 5-dimethylpyrazine dimer in the pile fermentation samples, 2, 4-heptadienal and 3-methylthiopropanal in the flowering stage samples, and 5-methylfurfural, butyl acrylate monomer, butyl acrylate dimer, furfural dimer, 2, 3-butanediol in the aging stage samples were higher than compared to other stages. Therefore, these compounds might be the potential indicators of the assessment of the piling fermentation, flowering and aging stage of Eucommia ulmoides leaves Fu brick tea, thus providing a tool for the regular monitoring of aroma components on the manufacturing process of Eucommia ulmoides leaves Fu brick tea.
2021, 42(21): 83-90.
DOI: 10.13386/j.issn1002-0306.2021030051
Abstract：
The chemical constituents of the essential oils from three Cymbopogon plants (C. winteranus, C. citratus and C. distans) were detected by GC-MS. Their antioxidant activity was investigated by the scavenging rate of DPPH free radicals and anti-inflammatory activity were evaluated by inhibition of lipopolysaccharide (LPS)-induced NO production in RAW264.7 cells. The results showed that terpenoids were the main chemical constituents of essential oils from three Cymbopogon plants, with the content of 76.35%~90.52%, of which terpene aldehydes and terpene alcohols were the highest. The main components of C. winteranus, C. citratus and C. distans were (+)-citronellal (37.85%), trans-citral (36.12%) and geraniol (34.76%), respectively. The DPPH radical scavenging activity of the three essential oils was dose-dependent, but lower than that of ascorbic acid (IC50=(0.005±0.002) mg/mL). At a lower concentration (2~4 μg/mL), the ability of three essential oil to reduce NO production was similar to dexamethasone (Dex, 10 μmol/L). The results showed that the three essential oils of Cymbopogon had significant anti-inflammatory activity, C. citratus (IC50 =(0.472±0.121) μg/mL) had the best anti-inflammatory activity, followed by C. winteranus (IC50 = (0.632±0.147) μg/mL) and C. distans (IC50 =(0.669±0.131) μg/mL). Thus they have great development potential as anti-inflammatory drugs and anti-inflammatory products.
The chemical constituents of the essential oils from three Cymbopogon plants (C. winteranus, C. citratus and C. distans) were detected by GC-MS. Their antioxidant activity was investigated by the scavenging rate of DPPH free radicals and anti-inflammatory activity were evaluated by inhibition of lipopolysaccharide (LPS)-induced NO production in RAW264.7 cells. The results showed that terpenoids were the main chemical constituents of essential oils from three Cymbopogon plants, with the content of 76.35%~90.52%, of which terpene aldehydes and terpene alcohols were the highest. The main components of C. winteranus, C. citratus and C. distans were (+)-citronellal (37.85%), trans-citral (36.12%) and geraniol (34.76%), respectively. The DPPH radical scavenging activity of the three essential oils was dose-dependent, but lower than that of ascorbic acid (IC50=(0.005±0.002) mg/mL). At a lower concentration (2~4 μg/mL), the ability of three essential oil to reduce NO production was similar to dexamethasone (Dex, 10 μmol/L). The results showed that the three essential oils of Cymbopogon had significant anti-inflammatory activity, C. citratus (IC50 =(0.472±0.121) μg/mL) had the best anti-inflammatory activity, followed by C. winteranus (IC50 = (0.632±0.147) μg/mL) and C. distans (IC50 =(0.669±0.131) μg/mL). Thus they have great development potential as anti-inflammatory drugs and anti-inflammatory products.
2021, 42(21): 91-99.
DOI: 10.13386/j.issn1002-0306.2021030055
Abstract：
Volatile flavor components of first-grade pressed rapeseed oil (S1) and fourth-grade pressed rapeseed oil (S2) subjected to accelerated oxidation test at 60 ℃ were profiled by means of headspace solid-phase microextraction with gas chromatography-mass spectrometry (HS-SPME-GC-MS) coupled with electronic nose (E-nose) technology, followed by correlation analysis with quality indicators. The results showed that the acid value of S1 and S2 was related to acid compounds. The content of aldehyde compounds had an important correlation with the degree of oxidation deterioration. The peroxide value of S1 was generally higher than that of S2. After 20 d of accelerated oxidation, S1 had a higher anisidine value than S2. S1 had a high oxidation rate in the early stage of oxidation, and S2 had a high oxidation rate in the later stage of oxidation. It showed that the deterioration degree of S1 was higher than that of S2. The main volatile components of rapeseed oil during accelerated oxidation were mainly aldehydes. The characteristic flavor components of S1 accelerated oxidation for 20 days were nonanal, decanal, 2,4-decadienal and 2-decanone. The characteristic flavor components of S2 accelerated oxidation for 20 days were (E)-2-decenal. The E-nose radar chart could distinguish unoxidized oil and oxidized oil, as well as the difference in flavor components in the early and late stages of oxidation. The content of (E)-2-decenal, (E)-2-nonenal, octanal and 2-undecenal were related to the peroxide value, anisidine value and total oxidation value of S1. The content of nonanal, (E,E)-2-4 decenal, (E)-2-decenal, (E)-2-nonenal, decanal, octyl aldehyde and heptanal were related to the peroxide value, anisidine value and total oxidation value of S2. Volatile components can be used as indicators to monitor the oxidation degree of rapeseed oil during storage.
Volatile flavor components of first-grade pressed rapeseed oil (S1) and fourth-grade pressed rapeseed oil (S2) subjected to accelerated oxidation test at 60 ℃ were profiled by means of headspace solid-phase microextraction with gas chromatography-mass spectrometry (HS-SPME-GC-MS) coupled with electronic nose (E-nose) technology, followed by correlation analysis with quality indicators. The results showed that the acid value of S1 and S2 was related to acid compounds. The content of aldehyde compounds had an important correlation with the degree of oxidation deterioration. The peroxide value of S1 was generally higher than that of S2. After 20 d of accelerated oxidation, S1 had a higher anisidine value than S2. S1 had a high oxidation rate in the early stage of oxidation, and S2 had a high oxidation rate in the later stage of oxidation. It showed that the deterioration degree of S1 was higher than that of S2. The main volatile components of rapeseed oil during accelerated oxidation were mainly aldehydes. The characteristic flavor components of S1 accelerated oxidation for 20 days were nonanal, decanal, 2,4-decadienal and 2-decanone. The characteristic flavor components of S2 accelerated oxidation for 20 days were (E)-2-decenal. The E-nose radar chart could distinguish unoxidized oil and oxidized oil, as well as the difference in flavor components in the early and late stages of oxidation. The content of (E)-2-decenal, (E)-2-nonenal, octanal and 2-undecenal were related to the peroxide value, anisidine value and total oxidation value of S1. The content of nonanal, (E,E)-2-4 decenal, (E)-2-decenal, (E)-2-nonenal, decanal, octyl aldehyde and heptanal were related to the peroxide value, anisidine value and total oxidation value of S2. Volatile components can be used as indicators to monitor the oxidation degree of rapeseed oil during storage.
2021, 42(21): 100-110.
DOI: 10.13386/j.issn1002-0306.2021040010
Abstract：
The impedance amplitude and phase angle of chilled chicken breast were measured with needle electrode and chip electrode, and the relationship between the measurement direction and the thickness of the test sample and the impedance characteristic value of chilled chicken breast was studied. The method of combining the principal component analysis score map and the DI value was used to evaluate the ability of the two electrodes to distinguish the characteristic value of chicken breast impedance. Quantitative analysis of variance was carried out on the impedance spectra of chicken breast obtained by the needle electrode, and the statistical method was used to determine the response ability of the needle electrode to the thickness change of the test sample. The results showed that the impedance amplitude measured perpendicular to the direction of the muscle fibers of chicken breast meat was greater than the impedance amplitude measured in the direction parallel to the muscle fibers, which was consistent with the anisotropy of biological tissues. At the same frequency, the impedance amplitude when the thickness of the test sample was 40 mm was higher than the impedance amplitude when the thickness of the test sample was 20 mm. The needle electrode had a good effect on distinguishing characteristic values of impedance in different measurement directions with 85.47% distinction index. It was statistically significant to use the needle electrode to measure the difference conversion of the impedance characteristic value of the chicken breast from low frequency to high frequency to distinguish different sample thicknesses (P<0.05). The measurement of impedance characteristic values through the needle electrode perpendicular to the direction of the chicken breast muscle fiber has high accuracy, which can provide a reference for the subsequent use of electrical impedance technology to achieve online rapid detection of chicken breast.
The impedance amplitude and phase angle of chilled chicken breast were measured with needle electrode and chip electrode, and the relationship between the measurement direction and the thickness of the test sample and the impedance characteristic value of chilled chicken breast was studied. The method of combining the principal component analysis score map and the DI value was used to evaluate the ability of the two electrodes to distinguish the characteristic value of chicken breast impedance. Quantitative analysis of variance was carried out on the impedance spectra of chicken breast obtained by the needle electrode, and the statistical method was used to determine the response ability of the needle electrode to the thickness change of the test sample. The results showed that the impedance amplitude measured perpendicular to the direction of the muscle fibers of chicken breast meat was greater than the impedance amplitude measured in the direction parallel to the muscle fibers, which was consistent with the anisotropy of biological tissues. At the same frequency, the impedance amplitude when the thickness of the test sample was 40 mm was higher than the impedance amplitude when the thickness of the test sample was 20 mm. The needle electrode had a good effect on distinguishing characteristic values of impedance in different measurement directions with 85.47% distinction index. It was statistically significant to use the needle electrode to measure the difference conversion of the impedance characteristic value of the chicken breast from low frequency to high frequency to distinguish different sample thicknesses (P<0.05). The measurement of impedance characteristic values through the needle electrode perpendicular to the direction of the chicken breast muscle fiber has high accuracy, which can provide a reference for the subsequent use of electrical impedance technology to achieve online rapid detection of chicken breast.
Abstract：
The changes in volatile compounds ofL. asiatica during controlled atmosphere storage (gas composition: O2 6% and CO2 10%, temperature: (5 ± 0.5) ℃, humidity: 90%) were investigated using electronic nose combined with gas chromatography-ion mobility spectrometry (GC-IMS). The results showed that aroma of the L. asiatica samples clearly changed during storage, particularly after 13 days, indicating the freshness reduced. There were 50 volatile compounds (monomer and dimers) detected using GC-IMS, including 16 aldehydes, 10 alcohols, 6 ketones, 1 acid, 1 ester and 16 un-identified compounds, the types and contents of volatile compounds were the highest at the 1st and 13th days of storage. During the controlled atmosphere storage, the types and content of aldehyde compounds decreased while that of keton compounds increased, benzene acetaldehyde and propanoic acid were the key arom compounds detected in L. asiatica. In general, electronic nose combined with GC-IMS could be an effective approach to quickly detect the freshness of the L. asiatica according to the volatiles changes.
The changes in volatile compounds of
2021, 42(21): 118-124.
DOI: 10.13386/j.issn1002-0306.2021010061
Abstract：
Four strains of endophytic fungi were isolated and purified from wild bodies of Leccinum crocipodium, Boletus speciosus, and Boletus bicolor by tissue separation method. Microscopic observation of its colonies, hyphae, and conidia morphology, and molecular biological identification of rDNA ITS sequence results showed that: Strain LCTG-12 was Trichoderma gamsii, LCCK-6 was Candida kruisii, BSHC-18 was Hypomyces chrysospermus, BBFO-10 was Fusarium oxysprum. The biological characteristics of four endophytic fungi studied, among them, the mycelium of Trichoderma gamsii growed faster, cultured on CPDA medium at 25 ℃ for 5 days, mycelium could cover the entire medium. In liquid culture, the strain could obtain 4.13 g/L of dry biomass of mycelium at 25 °C, shaker speed 160 r/min, pH5.5, and 8 days. The results of the flat panel stand-off experiment: LCTG-12 Trichoderma gamsii had an antagonistic effect on the growth of BSHC-18 Hypomyces chrysospermus and BBFO-10 Fusarium oxysprum, at the same time, BSHC-18 Hypomyces chrysospermus and BBFO-10 Fusarium oxysporum had an antagonistic effect. Therefore, the endophytic fungi Trichoderma gamsii of boletus had an antagonistic effect on spoilage fungi and may be an excellent strain for biological control.
Four strains of endophytic fungi were isolated and purified from wild bodies of Leccinum crocipodium, Boletus speciosus, and Boletus bicolor by tissue separation method. Microscopic observation of its colonies, hyphae, and conidia morphology, and molecular biological identification of rDNA ITS sequence results showed that: Strain LCTG-12 was Trichoderma gamsii, LCCK-6 was Candida kruisii, BSHC-18 was Hypomyces chrysospermus, BBFO-10 was Fusarium oxysprum. The biological characteristics of four endophytic fungi studied, among them, the mycelium of Trichoderma gamsii growed faster, cultured on CPDA medium at 25 ℃ for 5 days, mycelium could cover the entire medium. In liquid culture, the strain could obtain 4.13 g/L of dry biomass of mycelium at 25 °C, shaker speed 160 r/min, pH5.5, and 8 days. The results of the flat panel stand-off experiment: LCTG-12 Trichoderma gamsii had an antagonistic effect on the growth of BSHC-18 Hypomyces chrysospermus and BBFO-10 Fusarium oxysprum, at the same time, BSHC-18 Hypomyces chrysospermus and BBFO-10 Fusarium oxysporum had an antagonistic effect. Therefore, the endophytic fungi Trichoderma gamsii of boletus had an antagonistic effect on spoilage fungi and may be an excellent strain for biological control.
2021, 42(21): 125-132.
DOI: 10.13386/j.issn1002-0306.2021010200
Abstract：
Using sodium alginate as the sole carbon source medium, the microorganisms in Sargassum collected from Weizhou Island, Guangxi, were screened and isolated. The relative enzyme activity was determined by 3,5-Dinitrosalicylic acid (DNS) method, and the high-yield strain, marked M0101, was obtained. According to the morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis, the target strain was identified to belong to the genus of Vibrio, named as Vibrio gangliei M0101. The prioritization scheme of enzyme production of M0101 was confirmed by a single factor test: Alginate 50 g/L, (NH4)2SO4 2 g/L, K2HPO4 1 g/L, NaCl 100 g/L, MgSO4·7H2O 1 g/L, FeSO4·7H2O 0.01 g/L, 30 ℃, 200 r/min, initial pH9.0; and the maximum enzyme activity of strain M0101 reached 221.90 U/mL after optimation. It was 6.11 times higher than before(36.32 U/mL). Its efficiently hydrolysis of high concentration alginate and high salt tolerance, which has potential for large-scale preparation of alginate lyase.
Using sodium alginate as the sole carbon source medium, the microorganisms in Sargassum collected from Weizhou Island, Guangxi, were screened and isolated. The relative enzyme activity was determined by 3,5-Dinitrosalicylic acid (DNS) method, and the high-yield strain, marked M0101, was obtained. According to the morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis, the target strain was identified to belong to the genus of Vibrio, named as Vibrio gangliei M0101. The prioritization scheme of enzyme production of M0101 was confirmed by a single factor test: Alginate 50 g/L, (NH4)2SO4 2 g/L, K2HPO4 1 g/L, NaCl 100 g/L, MgSO4·7H2O 1 g/L, FeSO4·7H2O 0.01 g/L, 30 ℃, 200 r/min, initial pH9.0; and the maximum enzyme activity of strain M0101 reached 221.90 U/mL after optimation. It was 6.11 times higher than before(36.32 U/mL). Its efficiently hydrolysis of high concentration alginate and high salt tolerance, which has potential for large-scale preparation of alginate lyase.
2021, 42(21): 133-139.
DOI: 10.13386/j.issn1002-0306.2021010212
Abstract：
In order to improve the deficiency of mild-flavour fuqu baijiu, such as spicy, unmellow and soft flavor, Saccharomycopsis fibuligera was used in production to improve the quality of the original baijiu. Two kinds of Saccharomycopsis fibuligeras fuqu (Saccharomycopsis fibuligera T(NT), Saccharomycopsis fibuligera L(NL)) were prepared in the test. Sensory evaluation, flavor substance analysis, acid production capacity, saccharification power and fermentation power analysis of fuqu were conducted. The fuqu were applied in the brewing production of mild-flavour fuqu baijiu. The cereal baijiu yield rate, tasting substances of the original baijiu were analysed and their sensory quality of original baijiu were evaluated. The results showed that NL fuqu smelled creamy, floral. The floral fragrance was more obvious. NT fuqu smelled creamy, koji aroma. The koji aroma was more obvious. The contents of esters, ketones and acids of NL fuqu were 6.56%, 16.59% and 32.28% higher than that of NT fuqu, respectively, but the contents of aldehydes and alcohols were 5.67% and 2.67% lower than that of NT fuqu, respectively. Both fuqu had certain acid production ability, saccharification ability and fermentation ability. Compared with the control, the average baijiu yield rate of all test schemes was higher than that of the control under different test conditions, and the average baijiu yield rate of scheme 1 was the highest, which was about 4.62% higher than that of the control. The experimental schemes increased the sweetness of the original baijiu and the quality of base baijiu was also improved. The scheme had the value of popularization and application.
In order to improve the deficiency of mild-flavour fuqu baijiu, such as spicy, unmellow and soft flavor, Saccharomycopsis fibuligera was used in production to improve the quality of the original baijiu. Two kinds of Saccharomycopsis fibuligeras fuqu (Saccharomycopsis fibuligera T(NT), Saccharomycopsis fibuligera L(NL)) were prepared in the test. Sensory evaluation, flavor substance analysis, acid production capacity, saccharification power and fermentation power analysis of fuqu were conducted. The fuqu were applied in the brewing production of mild-flavour fuqu baijiu. The cereal baijiu yield rate, tasting substances of the original baijiu were analysed and their sensory quality of original baijiu were evaluated. The results showed that NL fuqu smelled creamy, floral. The floral fragrance was more obvious. NT fuqu smelled creamy, koji aroma. The koji aroma was more obvious. The contents of esters, ketones and acids of NL fuqu were 6.56%, 16.59% and 32.28% higher than that of NT fuqu, respectively, but the contents of aldehydes and alcohols were 5.67% and 2.67% lower than that of NT fuqu, respectively. Both fuqu had certain acid production ability, saccharification ability and fermentation ability. Compared with the control, the average baijiu yield rate of all test schemes was higher than that of the control under different test conditions, and the average baijiu yield rate of scheme 1 was the highest, which was about 4.62% higher than that of the control. The experimental schemes increased the sweetness of the original baijiu and the quality of base baijiu was also improved. The scheme had the value of popularization and application.
Abstract：
In order to study the characteristics and fermentation performance of high-yielding extracellular polysaccharide lactic acid bacteria in traditional yak yoghurt from Tibetan areas in Sichuan, six strains of high-yielding extracellular polysaccharide lactic acid bacteria isolated in our laboratory were taken as the research object, and the characteristics of strain growth, acid tolerance, bile salt tolerance, osmotic pressure tolerance and cell surface hydrophobicity were studied as the indexes. The fermentation performance of fermented yoghurt was studied with the indexes of coagulating time, water retention, acidification and post-acidification capacity, volatile substances and texture. The growth curve showed that the six strains entered the logarithmic growth stable stage at 14 h (218, 276, 266) and 16 h (271, 285, 231), respectively. Among them, the strain numbered 218 had the highest growth with OD value of 2.188. The results of tolerance test showed that strain 276 had good ability to tolerate acidity (P<0.05). Strains 266, 218 and 231 had strong bile salt resistance. All the six strains had good osmotic pressure tolerance, among which strain 285 had strong osmotic pressure tolerance. The hydrophobicity of strains 285 and 218 in the two organic reagents was significantly (P<0.05) higher than that of the other strains, and the binding effect with cetane was better. The results of fermentation test showed that the fermented yogurt of 6 strains coagulated within 6 h to 8 h, and the number of viable bacteria remained above 107 CFU/mL during the cold storage, which met the standard of starter culture. The highest value of strain 276 was 3.22×106 CFU/mL. The yoghurt produced by strain 218 had better texture characteristics, and its water holding capacity and acidification capacity were 60.98% and 83 °T, respectively, compared with those of the other strains. Strains 276 and 266 had better post-acidification resistance. Strain231 had the best aroma-producing property, with acetaldehyde content of 24~26 μg/mL and diacetyl content of 1.58~2.51 μg/mL, which could significantly improve the flavor of yoghurt. Through comprehensive comparison of the characteristics and fermentation performance of six strains of lactic acid bacteria with high extracellular polysaccharide yield, strain 218 was a strain with good performance and good stability, which can be used as a fermentation agent of lactic acid bacteria with certain application potential. This study provides a theoretical basis for the application of lactic acid bacteria with high extracellular polysaccharide yield isolated from traditional yak yoghurt in Tibetan area of Sichuan in the fermentation of dairy products.
In order to study the characteristics and fermentation performance of high-yielding extracellular polysaccharide lactic acid bacteria in traditional yak yoghurt from Tibetan areas in Sichuan, six strains of high-yielding extracellular polysaccharide lactic acid bacteria isolated in our laboratory were taken as the research object, and the characteristics of strain growth, acid tolerance, bile salt tolerance, osmotic pressure tolerance and cell surface hydrophobicity were studied as the indexes. The fermentation performance of fermented yoghurt was studied with the indexes of coagulating time, water retention, acidification and post-acidification capacity, volatile substances and texture. The growth curve showed that the six strains entered the logarithmic growth stable stage at 14 h (218, 276, 266) and 16 h (271, 285, 231), respectively. Among them, the strain numbered 218 had the highest growth with OD value of 2.188. The results of tolerance test showed that strain 276 had good ability to tolerate acidity (P<0.05). Strains 266, 218 and 231 had strong bile salt resistance. All the six strains had good osmotic pressure tolerance, among which strain 285 had strong osmotic pressure tolerance. The hydrophobicity of strains 285 and 218 in the two organic reagents was significantly (P<0.05) higher than that of the other strains, and the binding effect with cetane was better. The results of fermentation test showed that the fermented yogurt of 6 strains coagulated within 6 h to 8 h, and the number of viable bacteria remained above 107 CFU/mL during the cold storage, which met the standard of starter culture. The highest value of strain 276 was 3.22×106 CFU/mL. The yoghurt produced by strain 218 had better texture characteristics, and its water holding capacity and acidification capacity were 60.98% and 83 °T, respectively, compared with those of the other strains. Strains 276 and 266 had better post-acidification resistance. Strain231 had the best aroma-producing property, with acetaldehyde content of 24~26 μg/mL and diacetyl content of 1.58~2.51 μg/mL, which could significantly improve the flavor of yoghurt. Through comprehensive comparison of the characteristics and fermentation performance of six strains of lactic acid bacteria with high extracellular polysaccharide yield, strain 218 was a strain with good performance and good stability, which can be used as a fermentation agent of lactic acid bacteria with certain application potential. This study provides a theoretical basis for the application of lactic acid bacteria with high extracellular polysaccharide yield isolated from traditional yak yoghurt in Tibetan area of Sichuan in the fermentation of dairy products.
2021, 42(21): 148-157.
DOI: 10.13386/j.issn1002-0306.2021020127
Abstract：
In order to investigate the inhibitory effects of Kuding tea polyphenols on spoilage bacteria of Pseudomonas fluorescens from Trachinotus ovatus, Chromobacterium violaceum CV026 strain was used as a test model, investigated the effect of Kuding tea polyphenols on quorum sensing and spoilage capacity of P.luorescens. Taking extracellular enzyme activity, the amount and morphology of biofilm formation, clustering and motility as evaluation index, the inhibition effects of Kuding tea polyphenols on spoilage characteristics of Pseudomonas fluorescens were tested. The results showed that the minimum inhibitory concentration (MIC) of Kuding tea polyphenols against CV026 and P. fluorescenswas 2.1 and 3.0 mg/mL, and that Kuding tea polyphenols could significantly reduce the production of violacein in strain CV026 at sub-minimum inhibitory concentrations. When the concentration was 2.0 mg/mL, the inhibition ratio to violacein was 68.89%, while not affecting the growth of CV026 (P<0.05). Kuding tea polyphenols could effectively inhibit spoilage characteristics of Pseudomonas fluorescensas reflected by extracellular enzyme activity of Pseudomonas fluorescens, biofilm formation, swarming and swimming motility, and this effect was positively correlated with its concentration. When the mass concentration of Kuding tea polyphenols extract was 2.0 mg/mL, the inhibition rate of protease, lipase activity, formation of biofilm and the abilities of swarming and swimming motility were 80.68%, 53.50%, 44.90%, 79.56% and 90.12%. Kuding tea polyphenols has very good quorum sensing inhibitory activity, and can provide a reference to the research and development of new quorum sensing inhibitors.
In order to investigate the inhibitory effects of Kuding tea polyphenols on spoilage bacteria of Pseudomonas fluorescens from Trachinotus ovatus, Chromobacterium violaceum CV026 strain was used as a test model, investigated the effect of Kuding tea polyphenols on quorum sensing and spoilage capacity of P.luorescens. Taking extracellular enzyme activity, the amount and morphology of biofilm formation, clustering and motility as evaluation index, the inhibition effects of Kuding tea polyphenols on spoilage characteristics of Pseudomonas fluorescens were tested. The results showed that the minimum inhibitory concentration (MIC) of Kuding tea polyphenols against CV026 and P. fluorescenswas 2.1 and 3.0 mg/mL, and that Kuding tea polyphenols could significantly reduce the production of violacein in strain CV026 at sub-minimum inhibitory concentrations. When the concentration was 2.0 mg/mL, the inhibition ratio to violacein was 68.89%, while not affecting the growth of CV026 (P<0.05). Kuding tea polyphenols could effectively inhibit spoilage characteristics of Pseudomonas fluorescensas reflected by extracellular enzyme activity of Pseudomonas fluorescens, biofilm formation, swarming and swimming motility, and this effect was positively correlated with its concentration. When the mass concentration of Kuding tea polyphenols extract was 2.0 mg/mL, the inhibition rate of protease, lipase activity, formation of biofilm and the abilities of swarming and swimming motility were 80.68%, 53.50%, 44.90%, 79.56% and 90.12%. Kuding tea polyphenols has very good quorum sensing inhibitory activity, and can provide a reference to the research and development of new quorum sensing inhibitors.
2021, 42(21): 158-165.
DOI: 10.13386/j.issn1002-0306.2021030021
Abstract：
This study aimed to evaluate the quality changes and the growth of microorganisms of wet rice noodles with different preservation treatments during storage at 25 ℃, and analyzed the microbial diversity of spoiled samples based on Illumina Miseq high-throughput sequencing. The results indicated that the shelf life of control sample (CK) was only one day. The rice noodles became sticky and edible quality decreased significantly. Compared to the control, the shelf life of wet rice noodles treated by acid leaching (CA), acid leaching & ε-polylysine hydrochloride (PL), acid leaching & water bath (SY) could be extended to 2, 4 d and 13 d, respectively, and the main spoilage feature was mildew, differ from the control sample, which became sticky and smelly. The results of 16S rDNA indicated that the dominant spoilage bacteria in CK group were Pantoea, Sphingomonas and Bacillus. Different preservative treatments could significantly reduce the diversity of bacterial community. Among which, CA reduced the relative abundance of Sphingomonas and Bacillus, significantly. PL had good inhibitory effect on all three dominant bacterial genuses. ITS rDNA results showed that Rhizopus, belongs to Mucoromycota, was the dominant spoilage fungi in CK, however the relative abundance decreased to less than 0.1% after preservation treatments. While Ascomycota, with strong resistance to stress, became the dominant phylum after preservation treatments. This study provides a theoretical basis for the exploration of preservation technology of wet rice noodles.
This study aimed to evaluate the quality changes and the growth of microorganisms of wet rice noodles with different preservation treatments during storage at 25 ℃, and analyzed the microbial diversity of spoiled samples based on Illumina Miseq high-throughput sequencing. The results indicated that the shelf life of control sample (CK) was only one day. The rice noodles became sticky and edible quality decreased significantly. Compared to the control, the shelf life of wet rice noodles treated by acid leaching (CA), acid leaching & ε-polylysine hydrochloride (PL), acid leaching & water bath (SY) could be extended to 2, 4 d and 13 d, respectively, and the main spoilage feature was mildew, differ from the control sample, which became sticky and smelly. The results of 16S rDNA indicated that the dominant spoilage bacteria in CK group were Pantoea, Sphingomonas and Bacillus. Different preservative treatments could significantly reduce the diversity of bacterial community. Among which, CA reduced the relative abundance of Sphingomonas and Bacillus, significantly. PL had good inhibitory effect on all three dominant bacterial genuses. ITS rDNA results showed that Rhizopus, belongs to Mucoromycota, was the dominant spoilage fungi in CK, however the relative abundance decreased to less than 0.1% after preservation treatments. While Ascomycota, with strong resistance to stress, became the dominant phylum after preservation treatments. This study provides a theoretical basis for the exploration of preservation technology of wet rice noodles.
2021, 42(21): 166-172.
DOI: 10.13386/j.issn1002-0306.2021010165
Abstract：
The tuna cooking liquor obtained by extracting protein and oil was used as the raw material to produce the seafood condiment base through yeast fermentation. Sensory evaluation and amino acid nitrogen of the reaction products were determined and odor changes were analyzed using electronic nose. Through single-factor experiments, the influence of yeast type, added amount of yeast, fermentation time, and salinity on fermentation degree and product was studied. The optimal fermentation process was further determined through response surface design. The results showed that the optimal conditions for fermentation of bonito cooking liquor were: Yeast 71B, yeast addition amount 4.5‰, fermentation time 6 h, salinity 0.26 mol/L. Under this condition, the sensory score of the fermentation broth was 9.31. The amino acid composition showed that after fermentation, umami amino acids (Asp, Glu), sweet amino acids (Gly, Ala) all increased, and bitter amino acids (Val, His) decreased significantly.
The tuna cooking liquor obtained by extracting protein and oil was used as the raw material to produce the seafood condiment base through yeast fermentation. Sensory evaluation and amino acid nitrogen of the reaction products were determined and odor changes were analyzed using electronic nose. Through single-factor experiments, the influence of yeast type, added amount of yeast, fermentation time, and salinity on fermentation degree and product was studied. The optimal fermentation process was further determined through response surface design. The results showed that the optimal conditions for fermentation of bonito cooking liquor were: Yeast 71B, yeast addition amount 4.5‰, fermentation time 6 h, salinity 0.26 mol/L. Under this condition, the sensory score of the fermentation broth was 9.31. The amino acid composition showed that after fermentation, umami amino acids (Asp, Glu), sweet amino acids (Gly, Ala) all increased, and bitter amino acids (Val, His) decreased significantly.
Abstract：
In order to improve the comprehensive utilization of Lentinus edodes resources, on the basis of the existing Lentinus edodes sauce products, the appropriate optimization and recipe for preparing seasoning products with good sensory quality by using Lentinus edodes as the main recipe were discussed. In this paper, Lentinus edodes as the main raw materials produced in Guizhou, pepper and bean paste as the secondary material, by combining fuzzy mathematics sensory evaluation method optimal recipe of Lentinus edodes oil chili sauce, and its color, texture, physical and chemical indicators were analyzed. The results showed that the optimal recipe were: 52% Lentinus edodes, 16.5% chili, broad bean paste 13%, sugar 1.98%, salt 1.32% and flavor nucleotide disodium (I+G) 0.132% based on the basic recipe (edible oil 100 g, vinasse 8%, white sesame 2%, dried chili 3.3% and pepper powder 1.3%). This product sensory evaluation score of the recipe reached (88.75±3.07), and the product color was ruddy and shiny, the aroma was coordinated, and had a strong aroma of Lentinus edodes flavor, the Lentinus edodes granules were moderate in hardness and softness, the taste was distinct and delicious. The determined protein of the product was (5.58±0.47) g/100 g, moisture was (5.11±0.08) g/100 g, amino nitrogen was (4.87±0.06) g/100 g, and the microbiological index results were all qualified. This study can provide a theoretical basis for the deep processing of Lentinus edodes and other foreign grade products, and also lay the foundation for the comprehensive utilization of Lentinus edodes.
In order to improve the comprehensive utilization of Lentinus edodes resources, on the basis of the existing Lentinus edodes sauce products, the appropriate optimization and recipe for preparing seasoning products with good sensory quality by using Lentinus edodes as the main recipe were discussed. In this paper, Lentinus edodes as the main raw materials produced in Guizhou, pepper and bean paste as the secondary material, by combining fuzzy mathematics sensory evaluation method optimal recipe of Lentinus edodes oil chili sauce, and its color, texture, physical and chemical indicators were analyzed. The results showed that the optimal recipe were: 52% Lentinus edodes, 16.5% chili, broad bean paste 13%, sugar 1.98%, salt 1.32% and flavor nucleotide disodium (I+G) 0.132% based on the basic recipe (edible oil 100 g, vinasse 8%, white sesame 2%, dried chili 3.3% and pepper powder 1.3%). This product sensory evaluation score of the recipe reached (88.75±3.07), and the product color was ruddy and shiny, the aroma was coordinated, and had a strong aroma of Lentinus edodes flavor, the Lentinus edodes granules were moderate in hardness and softness, the taste was distinct and delicious. The determined protein of the product was (5.58±0.47) g/100 g, moisture was (5.11±0.08) g/100 g, amino nitrogen was (4.87±0.06) g/100 g, and the microbiological index results were all qualified. This study can provide a theoretical basis for the deep processing of Lentinus edodes and other foreign grade products, and also lay the foundation for the comprehensive utilization of Lentinus edodes.
2021, 42(21): 182-189.
DOI: 10.13386/j.issn1002-0306.2021020092
Abstract：
In order to explore the purification process of crayfish, ultrasonic cleaning technology and slightly acidic electrolyzed water bacteria reduction technology were used to purify living crayfish. In this paper, the total number of colonies and spores, the turbidity of the cleaning solution were used as evaluation indicators, and the available chlorine concentration of slightly acidic electrolyzed water, soaking time and ultrasonic power were single factor levels. The antibacterial effect of slightly acid electrolyzed water and the cleaning effect of ultrasonic technology on crayfish were studied. The results showed that the higher effective chlorine mass concentration of slightly acidic electrolyzed water, the longer treatment time, the better bacteria reduction effect. When the effective chlorine concentration of slightly acidic electrolyzed water was 60 mg/L, the total number of colonies and the total number of spores decreased by 4.26 lg CFU/g and 500 CFU/g after 50 minutes of treatment of crayfish, and the bacteria reduction rate reached 99.99% and 92.61%. The survival rate of crayfish was 100% after treatment with 50 W ultrasonic power for 50 min, and the turbidity of the cleaning solution was 181 NTU, which was significantly better than the control group (P<0.05). After synergistic work of ultrasonic technology and slightly acidic electrolyzed water in purify living crayfish, the initial bacteria of crayfish was decreased from 7.17 lg CFU/g to 3.52 lg CFU/g and the bacteria reduction rate was reached 99.98%, which was significantly better than the bubble cleaning process in workshop (P<0.05). There was no significant difference in the nutritional value and quality of crayfish after purification (P>0.05), and the process was reasonable and effective.
In order to explore the purification process of crayfish, ultrasonic cleaning technology and slightly acidic electrolyzed water bacteria reduction technology were used to purify living crayfish. In this paper, the total number of colonies and spores, the turbidity of the cleaning solution were used as evaluation indicators, and the available chlorine concentration of slightly acidic electrolyzed water, soaking time and ultrasonic power were single factor levels. The antibacterial effect of slightly acid electrolyzed water and the cleaning effect of ultrasonic technology on crayfish were studied. The results showed that the higher effective chlorine mass concentration of slightly acidic electrolyzed water, the longer treatment time, the better bacteria reduction effect. When the effective chlorine concentration of slightly acidic electrolyzed water was 60 mg/L, the total number of colonies and the total number of spores decreased by 4.26 lg CFU/g and 500 CFU/g after 50 minutes of treatment of crayfish, and the bacteria reduction rate reached 99.99% and 92.61%. The survival rate of crayfish was 100% after treatment with 50 W ultrasonic power for 50 min, and the turbidity of the cleaning solution was 181 NTU, which was significantly better than the control group (P<0.05). After synergistic work of ultrasonic technology and slightly acidic electrolyzed water in purify living crayfish, the initial bacteria of crayfish was decreased from 7.17 lg CFU/g to 3.52 lg CFU/g and the bacteria reduction rate was reached 99.98%, which was significantly better than the bubble cleaning process in workshop (P<0.05). There was no significant difference in the nutritional value and quality of crayfish after purification (P>0.05), and the process was reasonable and effective.
Abstract：
In order to obtain the optimum enzyme hydrolysis conditions and chelating properties of tilapia scale calcium binding peptides, and provide basis for study of promoting calcium absorption of active material, in this study, the decalcified tilapia scales as raw material and calcium chelation activity as an index, papain was selected to optimize enzyme hydrolysis of the tilapia scales to obtain tilapia scale calcium binding peptides. The properties of the tilapia scale calcium binding peptides were characterized by amino acid analysis, ultraviolet-visible spectroscopy and fourier transform infrared spectroscopy. The optimal enzymatic hydrolysis conditions were as follows: the concentration of substrate 8%, time 2 h, enzyme to substrate ratio 0.3%, pH7 and temperature 60 ℃. Under these conditions, the calcium chelation activity of the enzymatic hydrolysate was (38.31±0.4) µg/mL. The results of characterization showed that, after chelating calcium, the contents of aspartic acid, glutamic acid, glycine, lysine, serine, cysteine and histidine in peptide-calcium chelate increased by 0.88%, 1.48%, 0.34%, 0.53%, 0.04%, 0.38% and 0.46%, respectively. The carboxyl oxygen and amino nitrogen groups in the calcium binding peptides participated in binding with calcium ions to form the tilapia scale peptide-calcium chelate. Tilapia scale calcium binding peptides has high calcium chelation activity, which lays a foundation for the production and application of calcium supplements.
In order to obtain the optimum enzyme hydrolysis conditions and chelating properties of tilapia scale calcium binding peptides, and provide basis for study of promoting calcium absorption of active material, in this study, the decalcified tilapia scales as raw material and calcium chelation activity as an index, papain was selected to optimize enzyme hydrolysis of the tilapia scales to obtain tilapia scale calcium binding peptides. The properties of the tilapia scale calcium binding peptides were characterized by amino acid analysis, ultraviolet-visible spectroscopy and fourier transform infrared spectroscopy. The optimal enzymatic hydrolysis conditions were as follows: the concentration of substrate 8%, time 2 h, enzyme to substrate ratio 0.3%, pH7 and temperature 60 ℃. Under these conditions, the calcium chelation activity of the enzymatic hydrolysate was (38.31±0.4) µg/mL. The results of characterization showed that, after chelating calcium, the contents of aspartic acid, glutamic acid, glycine, lysine, serine, cysteine and histidine in peptide-calcium chelate increased by 0.88%, 1.48%, 0.34%, 0.53%, 0.04%, 0.38% and 0.46%, respectively. The carboxyl oxygen and amino nitrogen groups in the calcium binding peptides participated in binding with calcium ions to form the tilapia scale peptide-calcium chelate. Tilapia scale calcium binding peptides has high calcium chelation activity, which lays a foundation for the production and application of calcium supplements.
2021, 42(21): 197-204.
DOI: 10.13386/j.issn1002-0306.2021030040
Abstract：
The effects of four improver (tripolyphosphate, xanthan gum, wheat gluten and potato modified starch) on the quality of instant dough slice were investigated by single factor test with texture and cooking characteristics (cooking loss rate, rehydration time) as evaluation indexes. On this basis, response surface (RSM) combined with principal component analysis (PCA) was used to optimize the formula of instant dough slice. The results suggested that wheat flour as the main raw materials, wheat gluten improver added quantity 1.4%, the triplephosphate 0.3%, xanthan gum 0.3%, potato modified starch 10%. Under these conditions, the ductility, hardness, masticability, cooking loss rate, and rehydration time of the plate were （69.81±8.73）g·s, （766.94±58.90）g, （3227.44±263.14）g·s, （1.95%±0.03%） and （350±7.51）s, which were basically consistent with the theoretical values, indicating that the model had a good fitting degree and it could be used as the formula of instant dough slice in the production of soup noodle.
The effects of four improver (tripolyphosphate, xanthan gum, wheat gluten and potato modified starch) on the quality of instant dough slice were investigated by single factor test with texture and cooking characteristics (cooking loss rate, rehydration time) as evaluation indexes. On this basis, response surface (RSM) combined with principal component analysis (PCA) was used to optimize the formula of instant dough slice. The results suggested that wheat flour as the main raw materials, wheat gluten improver added quantity 1.4%, the triplephosphate 0.3%, xanthan gum 0.3%, potato modified starch 10%. Under these conditions, the ductility, hardness, masticability, cooking loss rate, and rehydration time of the plate were （69.81±8.73）g·s, （766.94±58.90）g, （3227.44±263.14）g·s, （1.95%±0.03%） and （350±7.51）s, which were basically consistent with the theoretical values, indicating that the model had a good fitting degree and it could be used as the formula of instant dough slice in the production of soup noodle.
2021, 42(21): 205-212.
DOI: 10.13386/j.issn1002-0306.2021030056
Abstract：
This study utilized pea protein isolate, pea tissue protein and gluten as the main protein materials in the production of plant-based sausage. Textural properties, cooking loss, and sensory evaluation were analyzed to determine the protein formula of the sausage. On the basis of single factor experiment, Box-Behnken response surface test was used to optimize the formula of plant-based sausage. Results showed that the sausage composed of 19.19% pea protein isolate, 9.83% tissue protein and 7.13% gluten powder was the best. Under these conditions, the sensory score of sausage was 81.20, which was close to the predicted value of 80.11. The chewiness was 4791.2 g·s, which was close to the predicted value of 4767.09 g·s.The optimized plant-based sausage has hardness of 6245.11 g, cohesion of 0.83, recovery of 0.51% and cooking loss rate of 2.72%, compared with the commercially available plant-based sausage, the cooking loss rate was lower, the cohesiveness and resilience were better, and the hardness was within the hardness range of commercially available sausage. This study would provide guidance for the development of plant-based products and related industrial production.
This study utilized pea protein isolate, pea tissue protein and gluten as the main protein materials in the production of plant-based sausage. Textural properties, cooking loss, and sensory evaluation were analyzed to determine the protein formula of the sausage. On the basis of single factor experiment, Box-Behnken response surface test was used to optimize the formula of plant-based sausage. Results showed that the sausage composed of 19.19% pea protein isolate, 9.83% tissue protein and 7.13% gluten powder was the best. Under these conditions, the sensory score of sausage was 81.20, which was close to the predicted value of 80.11. The chewiness was 4791.2 g·s, which was close to the predicted value of 4767.09 g·s.The optimized plant-based sausage has hardness of 6245.11 g, cohesion of 0.83, recovery of 0.51% and cooking loss rate of 2.72%, compared with the commercially available plant-based sausage, the cooking loss rate was lower, the cohesiveness and resilience were better, and the hardness was within the hardness range of commercially available sausage. This study would provide guidance for the development of plant-based products and related industrial production.
2021, 42(21): 213-220.
DOI: 10.13386/j.issn1002-0306.2021030105
Abstract：
The aim of this study was to optimize the extraction process of Ligusticum chuanxiong protein (LCP) and to investigate its antioxidant activity. Based on single factor experiment, Box-Behnken response surface methodology was used to optimize the extraction process of LCP, with solid-liquid ratio, extraction time, extraction solvent pH as the factors, and extraction rate of LCP as the index. The molecular weight range of LCP was determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The isoelectric point (pI) and solubility of LCP were determined, and the antioxidant activity of LCP was investigated. The results showed that the optimal extraction conditions were solid-liquid ratio of 1:15 (g/mL), extraction time of 1.5 h and pH of 6. Under the optimized conditions, the extraction yield of LCP was （2.36%±0.13%）, and the measured value was close to the theoretical value, indicating that the mathematical model could be used to optimize the extraction process of LCP. Under the optimal conditions, the molecular weight of the extracted LCP was 17~48 kDa, the isoelectric point was 3.88, the solubility was 96% at pH8. The IC50 of hydroxyl radical scavenging activity was 1.18 mg/mL, the IC50 of superoxide anion radical scavenging activity was 0.57 mg/mL, and the IC50 of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was 1.31 mg/mL. LCP extracted by this method has good antioxidant activity, which can provide experimental ideas for further research and development of LCP antioxidant activity.
The aim of this study was to optimize the extraction process of Ligusticum chuanxiong protein (LCP) and to investigate its antioxidant activity. Based on single factor experiment, Box-Behnken response surface methodology was used to optimize the extraction process of LCP, with solid-liquid ratio, extraction time, extraction solvent pH as the factors, and extraction rate of LCP as the index. The molecular weight range of LCP was determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The isoelectric point (pI) and solubility of LCP were determined, and the antioxidant activity of LCP was investigated. The results showed that the optimal extraction conditions were solid-liquid ratio of 1:15 (g/mL), extraction time of 1.5 h and pH of 6. Under the optimized conditions, the extraction yield of LCP was （2.36%±0.13%）, and the measured value was close to the theoretical value, indicating that the mathematical model could be used to optimize the extraction process of LCP. Under the optimal conditions, the molecular weight of the extracted LCP was 17~48 kDa, the isoelectric point was 3.88, the solubility was 96% at pH8. The IC50 of hydroxyl radical scavenging activity was 1.18 mg/mL, the IC50 of superoxide anion radical scavenging activity was 0.57 mg/mL, and the IC50 of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was 1.31 mg/mL. LCP extracted by this method has good antioxidant activity, which can provide experimental ideas for further research and development of LCP antioxidant activity.
2021, 42(21): 221-230.
DOI: 10.13386/j.issn1002-0306.2021030374
Abstract：
In order to develop the industrial process of high-quality instant crayfish (Procambarus clarkii) products, the microwave sterilization processes were designed based on the 896 MHz single-mode microwave sterilization system. Effects of microwave sterilization on crayfish quality were studied by calculating cooking value, water holding capacity, texture analysis, color analysis, sensory evaluation and taste profile analysis of electronic tongue. Study results indicated the sterilization conditions of keeping the microwave in power of 6.5 kW and pressure of 0.2 MPa, microwave treating for 190 s, holding at （120±1）℃ for 180 s could achieve the level of thermal lethality of F0=2 min, which was the minimum thermal lethality value satisfying the requirements of commercial sterility. The shelf life of the instant crayfish treated by the microwave sterilization process could be more than 6 months at room temperature. The total processing time, cooking value of cold spot and surface in microwave sterilization group were significantly reduced by 66.55%, 34.40%, and 57.75% than those of traditional sterilization treatments, respectively. Moreover, the water holding capacity and texture of crayfish in experimental microwave sterilization group were much higher compared to the traditional sterilization treated group (P<0.05), and there was no significant difference of ratio of intact tail were found in both groups (P>0.05). However, the color of muscle of crayfish treated with microwave sterilization turned yellower than that of traditional sterilization group. During the storage period, the taste profile of microwave sterilization group did not change significantly, and the sensory score of microwave sterilization group was higher than that of traditional sterilization group. In conclusion, microwave sterilization technology can be used in the processing of room-temperature instant crayfish products.
In order to develop the industrial process of high-quality instant crayfish (Procambarus clarkii) products, the microwave sterilization processes were designed based on the 896 MHz single-mode microwave sterilization system. Effects of microwave sterilization on crayfish quality were studied by calculating cooking value, water holding capacity, texture analysis, color analysis, sensory evaluation and taste profile analysis of electronic tongue. Study results indicated the sterilization conditions of keeping the microwave in power of 6.5 kW and pressure of 0.2 MPa, microwave treating for 190 s, holding at （120±1）℃ for 180 s could achieve the level of thermal lethality of F0=2 min, which was the minimum thermal lethality value satisfying the requirements of commercial sterility. The shelf life of the instant crayfish treated by the microwave sterilization process could be more than 6 months at room temperature. The total processing time, cooking value of cold spot and surface in microwave sterilization group were significantly reduced by 66.55%, 34.40%, and 57.75% than those of traditional sterilization treatments, respectively. Moreover, the water holding capacity and texture of crayfish in experimental microwave sterilization group were much higher compared to the traditional sterilization treated group (P<0.05), and there was no significant difference of ratio of intact tail were found in both groups (P>0.05). However, the color of muscle of crayfish treated with microwave sterilization turned yellower than that of traditional sterilization group. During the storage period, the taste profile of microwave sterilization group did not change significantly, and the sensory score of microwave sterilization group was higher than that of traditional sterilization group. In conclusion, microwave sterilization technology can be used in the processing of room-temperature instant crayfish products.
2021, 42(21): 231-240.
DOI: 10.13386/j.issn1002-0306.2021060195
Abstract：
In order to enrich the varieties of dried meat slice and improve the nutritional value of dried meat slice, the effects of water to natto ratio, natto liquid addition, fermentation time and sucrose addition on the quality of natto fermented dried meat slice (NDMS) were studied with shear force, moisture content, color difference and sensory score as indexes. On this basis, the shear force and sensory score were used as response values, the fermentation process condition was optimized by using response surface design. The results showed that the optimal technology of natto fermented dried meat slice were as follows: the ratio of water to natto was 1.5:1, the amount of natto liquid was (8.0 g/100 g), the fermentation time was 18 h, and the amount of sucrose was (20.7 g/100 g). Under these conditions, the prepared dried meat slice has bright red color, unique aroma and taste of natto, good tenderness, good taste, high protein (38.6 g/100 g) and low fat (8.4 g/100 g), the measured shear force was (49.86±0.29) N, and the sensory score was (93.25±0.58). There was no significant difference with the predicted value of the model. The model has good fitting and reliable test results.
In order to enrich the varieties of dried meat slice and improve the nutritional value of dried meat slice, the effects of water to natto ratio, natto liquid addition, fermentation time and sucrose addition on the quality of natto fermented dried meat slice (NDMS) were studied with shear force, moisture content, color difference and sensory score as indexes. On this basis, the shear force and sensory score were used as response values, the fermentation process condition was optimized by using response surface design. The results showed that the optimal technology of natto fermented dried meat slice were as follows: the ratio of water to natto was 1.5:1, the amount of natto liquid was (8.0 g/100 g), the fermentation time was 18 h, and the amount of sucrose was (20.7 g/100 g). Under these conditions, the prepared dried meat slice has bright red color, unique aroma and taste of natto, good tenderness, good taste, high protein (38.6 g/100 g) and low fat (8.4 g/100 g), the measured shear force was (49.86±0.29) N, and the sensory score was (93.25±0.58). There was no significant difference with the predicted value of the model. The model has good fitting and reliable test results.
2021, 42(21): 241-248.
DOI: 10.13386/j.issn1002-0306.2020120165
Abstract：
The extraction conditions for volatile compounds of Dancong tea by headspace solid phase micro-extraction, including the extraction time, the temperature and the ratio of tea and water, were optimized. Each sample was detected and analyzed by gas chromatography-mass spectrometry （GC-MS） to establish the volatile substance fingerprint of Dancong tea. The results showed that the optimal extraction conditions were 0.75:5 g/mL tea-water ratio, and extraction was performed at 90 ℃ for 50 min. The volatile substances fingerprints of Dancong tea identified 20 common peaks and the similarity was above 0.9. The discriminant model had good accuracy for the classification of Dancong tea in different regions. The accuracy rate of its own verification method and the interactive verification method were 100% while the external verification method was 80%. The results can provide experimental basis for the headspace solid phase microextraction of Dancong tea and provide a theoretical reference for the identification of Dancong tea.
The extraction conditions for volatile compounds of Dancong tea by headspace solid phase micro-extraction, including the extraction time, the temperature and the ratio of tea and water, were optimized. Each sample was detected and analyzed by gas chromatography-mass spectrometry （GC-MS） to establish the volatile substance fingerprint of Dancong tea. The results showed that the optimal extraction conditions were 0.75:5 g/mL tea-water ratio, and extraction was performed at 90 ℃ for 50 min. The volatile substances fingerprints of Dancong tea identified 20 common peaks and the similarity was above 0.9. The discriminant model had good accuracy for the classification of Dancong tea in different regions. The accuracy rate of its own verification method and the interactive verification method were 100% while the external verification method was 80%. The results can provide experimental basis for the headspace solid phase microextraction of Dancong tea and provide a theoretical reference for the identification of Dancong tea.
2021, 42(21): 249-261.
DOI: 10.13386/j.issn1002-0306.2021010005
Abstract：
In order to explore the effect of hot air drying temperature on the quality of Ficus hirta Vahl. segments, slices, and fibrous roots, high-performance liquid chromatography, ultraviolet visible spectrophotometry and dead space solid phase micro extraction-GC/MS were used in this study to determine the contents of psoralen, polyphenols, flavonoids, soluble sugars and volatile flavor compounds in samples dried respectively at 40, 50, 60 and 70 ℃, and the sun-dried sample was used as control. The results showed that as the drying temperature rises, the contents of psoralen in Ficus hirta Vahl. Segments and fibrous roots increased at first and then decreased, polyphenols slightly increased, but their contents were not affected by temperature in slices. The contents of flavonoids in the segments, slices and fibrous roots of Ficus hirta Vahl. were all increased first and then decreased, and the contents of soluble sugar were all decreased slightly compared with sun-dried sample. The compositions and relative contents of flavoring substances changed greatly. When samples dried at 50~60 ℃, the contents of psoralen in Ficus hirta Vahl. segments, slices, and fibrous roots were 0.5, 0.3 and 1.29 mg/g, respectively, and the contents of total polyphenols were 1.6, 1.3, 3.5 mg/g, respectively, and the contents of total flavones were 1.5, 1.0, 3.45 mg/g, respectively, and the content of soluble sugar was 70~80 mg/g, and the relative contents of aldehydes, pyrazine and naphthalene were 12.75%, 5.87% and 14.66%, respectively. Therefore, in the actual production process, hot air drying at 50~60 ℃ can be used instead of drying in the shade or sun-dried. This research provides a data reference for the hot-air drying processing of Ficus hirta Vahl.
In order to explore the effect of hot air drying temperature on the quality of Ficus hirta Vahl. segments, slices, and fibrous roots, high-performance liquid chromatography, ultraviolet visible spectrophotometry and dead space solid phase micro extraction-GC/MS were used in this study to determine the contents of psoralen, polyphenols, flavonoids, soluble sugars and volatile flavor compounds in samples dried respectively at 40, 50, 60 and 70 ℃, and the sun-dried sample was used as control. The results showed that as the drying temperature rises, the contents of psoralen in Ficus hirta Vahl. Segments and fibrous roots increased at first and then decreased, polyphenols slightly increased, but their contents were not affected by temperature in slices. The contents of flavonoids in the segments, slices and fibrous roots of Ficus hirta Vahl. were all increased first and then decreased, and the contents of soluble sugar were all decreased slightly compared with sun-dried sample. The compositions and relative contents of flavoring substances changed greatly. When samples dried at 50~60 ℃, the contents of psoralen in Ficus hirta Vahl. segments, slices, and fibrous roots were 0.5, 0.3 and 1.29 mg/g, respectively, and the contents of total polyphenols were 1.6, 1.3, 3.5 mg/g, respectively, and the contents of total flavones were 1.5, 1.0, 3.45 mg/g, respectively, and the content of soluble sugar was 70~80 mg/g, and the relative contents of aldehydes, pyrazine and naphthalene were 12.75%, 5.87% and 14.66%, respectively. Therefore, in the actual production process, hot air drying at 50~60 ℃ can be used instead of drying in the shade or sun-dried. This research provides a data reference for the hot-air drying processing of Ficus hirta Vahl.
Abstract：
A determination method of three kinds of triazine pesticides(Atrazine, Cyromazine and Metolachlor) residue in milk and dairy products by isotope dilution-high performance liquid chromatography-high resolution mass spectrometry was established. The samples were extracted by acetonitrile and purified by C18 solid phase extraction column. The mobile phase program was gradient elution with 0.1% formic acid aqueous solution. The samples were separated by Hypersil Gold C18 column. Electrospray positive ions (HESI+) and full MS/dd-MS2 mode were used for qualitative and quantitative detection. The results showed that the linearities relationship were good in the range of 1.0~50.0 ng/mL (R2≥0.99). The detection limits of this method were 5 μg/kg, and the average recoveries were 81.6%~104.0% and the relative standard deviations were 0.55%~4.14% with levers of 5, 10 and 25 μg/kg. The method is suitable for the determination of three kinds of triazine pesticides residues in milk and dairy products, with high sensitivity, good reproducibility and reliable results. It provides technical support for ensuring the food safety of milk and dairy products in China.
A determination method of three kinds of triazine pesticides(Atrazine, Cyromazine and Metolachlor) residue in milk and dairy products by isotope dilution-high performance liquid chromatography-high resolution mass spectrometry was established. The samples were extracted by acetonitrile and purified by C18 solid phase extraction column. The mobile phase program was gradient elution with 0.1% formic acid aqueous solution. The samples were separated by Hypersil Gold C18 column. Electrospray positive ions (HESI+) and full MS/dd-MS2 mode were used for qualitative and quantitative detection. The results showed that the linearities relationship were good in the range of 1.0~50.0 ng/mL (R
Abstract：
An analytical method based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for detecting 4 kinds of frequently-used spices (maltol, ethyl-maltol, vanillin and ethyl-vanillin) in dairy products. The samples were extracted by water and tert butyl methyl ether, the supernatants were extracted by 0.2 mol/L sodium hydroxide solution alkali solution (the volume ratio of alkali solution to MTBE was 1:5) for purification and enrichment of target composes to the aqueous phase. The separation of these 4 compounds was carried out by a HSS T3 column and the mobile phase performed on 0.05% formic acid aqueous solution-methanol by gradient elution, electrospray ionization source (ESI) was applied and operated in the positive mode. Multiple reaction monitoring (MRM) mode was used to monitor ions. The results showed that the method had a good linearity range between 2.0~100.0 ng/mL (R2>0.995) and the detection limits were as low as 8.0 μg/kg. The matrix effects of 4 kinds of spices in different dairy products showed week matrix suppression effects and ranged from 80%~100%, suggesting the matrix effects advisably being ignored in routine testing. The average recoveries of the targeted compounds range from 67.7% to 104.8% at spiked levels of 10, 25 and 100 μg /kg, and relative standard deviations range from 2.5% to 11.9% (n=6). The method is simple, sensitive, accurate and reliable.
An analytical method based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed for detecting 4 kinds of frequently-used spices (maltol, ethyl-maltol, vanillin and ethyl-vanillin) in dairy products. The samples were extracted by water and tert butyl methyl ether, the supernatants were extracted by 0.2 mol/L sodium hydroxide solution alkali solution (the volume ratio of alkali solution to MTBE was 1:5) for purification and enrichment of target composes to the aqueous phase. The separation of these 4 compounds was carried out by a HSS T3 column and the mobile phase performed on 0.05% formic acid aqueous solution-methanol by gradient elution, electrospray ionization source (ESI) was applied and operated in the positive mode. Multiple reaction monitoring (MRM) mode was used to monitor ions. The results showed that the method had a good linearity range between 2.0~100.0 ng/mL (R2>0.995) and the detection limits were as low as 8.0 μg/kg. The matrix effects of 4 kinds of spices in different dairy products showed week matrix suppression effects and ranged from 80%~100%, suggesting the matrix effects advisably being ignored in routine testing. The average recoveries of the targeted compounds range from 67.7% to 104.8% at spiked levels of 10, 25 and 100 μg /kg, and relative standard deviations range from 2.5% to 11.9% (n=6). The method is simple, sensitive, accurate and reliable.
2021, 42(21): 279-284.
DOI: 10.13386/j.issn1002-0306.2021010202
Abstract：
The aim of this study was to establish a method for the determination of dihydroquercetin, a new food additive, in dairy products by High-performance liquid chromatography. The dihydroquercetin was extracted by acetonitrile /water solution, then was purified by extraction column with Polystyrene / divinylbenzene Copolymer (HLB or PLS). After separation by C18 reversed-phase chromatographic column, the content of dihydroquercetin was detected by the UV detector detection. The results showed that the linear range of dihydroquercetin was 0.5~20 μg/mL, the linear correlation coefficient was 0.9997, the recovery range of different kinds of samples was 86.0%~101%, the precision RSD was 2.06% (n=6).The method has good reproducibility and high accuracy. It can provide reference for the determination of dihydroquercetin in food and the establishment of national standard.
The aim of this study was to establish a method for the determination of dihydroquercetin, a new food additive, in dairy products by High-performance liquid chromatography. The dihydroquercetin was extracted by acetonitrile /water solution, then was purified by extraction column with Polystyrene / divinylbenzene Copolymer (HLB or PLS). After separation by C18 reversed-phase chromatographic column, the content of dihydroquercetin was detected by the UV detector detection. The results showed that the linear range of dihydroquercetin was 0.5~20 μg/mL, the linear correlation coefficient was 0.9997, the recovery range of different kinds of samples was 86.0%~101%, the precision RSD was 2.06% (n=6).The method has good reproducibility and high accuracy. It can provide reference for the determination of dihydroquercetin in food and the establishment of national standard.
2021, 42(21): 285-293.
DOI: 10.13386/j.issn1002-0306.2021020076
Abstract：
The purpose of this experiment was to study the differences of volatile flavor substances and fatty acid composition in different parts of Small-Tailed Han Lambs, and to preliminarily evaluate the nutritional value of fatty acids in four parts. The contents of fat, protein, volatile flavor substances and fatty acid in hind leg, tenderloin, upper brain and lamb chop of 4-month-old Small-Tailed Han Lambs were analyzed. The results showed that the main flavor compounds of Small-Tailed Han Lambs were octanal, nonanal, octanol, 1-octene-3-ol, caprylic acid and decanoic acid. The types and relative contents of aldehydes, alcohols and esters in the tenderloin were high, which played an important role in the formation of mutton flavor. The ratio of unsaturated fatty acids to saturated fatty acids in upper brain was significantly higher than that in other parts, the ratio of polyunsaturated fatty acids to saturated fatty acids was more than 0.4, and the contents of monounsaturated fatty acids and polyunsaturated fatty acids were both high. Therefore, the composition of fatty acids in the upper brain is more consistent with the nutritional value of fatty acids.
The purpose of this experiment was to study the differences of volatile flavor substances and fatty acid composition in different parts of Small-Tailed Han Lambs, and to preliminarily evaluate the nutritional value of fatty acids in four parts. The contents of fat, protein, volatile flavor substances and fatty acid in hind leg, tenderloin, upper brain and lamb chop of 4-month-old Small-Tailed Han Lambs were analyzed. The results showed that the main flavor compounds of Small-Tailed Han Lambs were octanal, nonanal, octanol, 1-octene-3-ol, caprylic acid and decanoic acid. The types and relative contents of aldehydes, alcohols and esters in the tenderloin were high, which played an important role in the formation of mutton flavor. The ratio of unsaturated fatty acids to saturated fatty acids in upper brain was significantly higher than that in other parts, the ratio of polyunsaturated fatty acids to saturated fatty acids was more than 0.4, and the contents of monounsaturated fatty acids and polyunsaturated fatty acids were both high. Therefore, the composition of fatty acids in the upper brain is more consistent with the nutritional value of fatty acids.
Abstract：
Objective: To establish a quantitative analysis of multi-components by single-marker (QAMS) with using glutamic acid as the internal reference, the content of 17 amino acids in Morchella esculenta was determined simultaneously. Methods: High performance liquid chromatography (HPLC) was used with acetonitrile-ammonium acetate aqueous solution as mobile phase, gradient elution and glutamic as the internal reference substance was used to establish its relative correction factors (RCF) of other 16 amino acids. The content of 17 amino acids in Morchella esculenta was calculated by using the relative correction factor. Internal standard method was used to determine 17 amino acids in Morchella esculenta. The validity of the QAMS method was evaluated by comparison of the quantitative results of both methods and to validate the durability of this method. Results: The 17 amino acids had a great linear relationship in the linear range, and the correlation coefficients higher than 0.9990, the average recovery rate of 17 amino acids were in the range of 92.42%~101.16%, and the relative standard deviations (RSD) were in the range of 0.25%~1.94%, and reproducibility was good in different experimental conditions (RSD<2.0%); through the comparative analysis of determination results of QAMS and the internal standanrd method, the two methods had no significant difference (P>0.05). The RCF and the relative retention time RSD in different chromatographic columns and chromatographic systems all less than 2.0%, and the durability was good. Conclusion: This method is simple, easy to operate, accurate and can save the cost of content determination. It can be used as a new model for the determination of amino acid content in Morchella esculenta, and can also provide a valuable reference for the quality evaluation of Morchella esculenta.
Objective: To establish a quantitative analysis of multi-components by single-marker (QAMS) with using glutamic acid as the internal reference, the content of 17 amino acids in Morchella esculenta was determined simultaneously. Methods: High performance liquid chromatography (HPLC) was used with acetonitrile-ammonium acetate aqueous solution as mobile phase, gradient elution and glutamic as the internal reference substance was used to establish its relative correction factors (RCF) of other 16 amino acids. The content of 17 amino acids in Morchella esculenta was calculated by using the relative correction factor. Internal standard method was used to determine 17 amino acids in Morchella esculenta. The validity of the QAMS method was evaluated by comparison of the quantitative results of both methods and to validate the durability of this method. Results: The 17 amino acids had a great linear relationship in the linear range, and the correlation coefficients higher than 0.9990, the average recovery rate of 17 amino acids were in the range of 92.42%~101.16%, and the relative standard deviations (RSD) were in the range of 0.25%~1.94%, and reproducibility was good in different experimental conditions (RSD<2.0%); through the comparative analysis of determination results of QAMS and the internal standanrd method, the two methods had no significant difference (P>0.05). The RCF and the relative retention time RSD in different chromatographic columns and chromatographic systems all less than 2.0%, and the durability was good. Conclusion: This method is simple, easy to operate, accurate and can save the cost of content determination. It can be used as a new model for the determination of amino acid content in Morchella esculenta, and can also provide a valuable reference for the quality evaluation of Morchella esculenta.
Abstract：
In order to provide technology support for quality “Gui-pu No.1” Vitis quinnquangularis Rehd winemaking, the quantitative method of 9 classic phenolic compounds was developed by HPLC, and the changes of their fermentation process were tracked. After wave length and gradient optimization, the final optimized analytical condition were fixed as follows: The column was Atlanis T3 column(4.6 mm×250 mm, 5 μm), flow rate was 1 mL/min, gradient elution was adopted, column temperature was 30 ℃, detection wavelength was 280, 306, 320, 360 nm, respectively, and sample loading volume was 10 μL. This method was proven to be a wide linear range, R2>0.989, as well as quantitative limits were from 0.056 to 0.987 mg/L, recovery rates of gradient 4 of mixed standards were from 92.37% to 103.45%, relative standard deviations were not more than 3.26%. The results showed as following: Only kaempferol was not detected in the initial fermentation broth. The changes module of different phenolic acid contents in the ferment broth of “Gui-pu No.1” during fermentation process at 22 ℃ and 28 ℃ were different. In contrast the declining trend of polydatin and chlorogenic acid during fermentation process, the changes of other phenolic compounds showed as a trend of increasing first and then decreasing. The variation trends of same compound at different fermentation temperature of 22 ℃ and 28 ℃ were basically the same, but the variation magnitudes were different. In the fermentation broths at 22 ℃ and 28 ℃ for 15 d, only the contents of cyandin-3-O-glucoside, kaempferol and ferulic acid were all higher than those in the initial fermentation broths. This study provided effective quality controlling means and preliminary data support for the quality production of phenolic compounds in Vitis quinnquangularis Rehd winemaking.
In order to provide technology support for quality “Gui-pu No.1” Vitis quinnquangularis Rehd winemaking, the quantitative method of 9 classic phenolic compounds was developed by HPLC, and the changes of their fermentation process were tracked. After wave length and gradient optimization, the final optimized analytical condition were fixed as follows: The column was Atlanis T3 column(4.6 mm×250 mm, 5 μm), flow rate was 1 mL/min, gradient elution was adopted, column temperature was 30 ℃, detection wavelength was 280, 306, 320, 360 nm, respectively, and sample loading volume was 10 μL. This method was proven to be a wide linear range, R2>0.989, as well as quantitative limits were from 0.056 to 0.987 mg/L, recovery rates of gradient 4 of mixed standards were from 92.37% to 103.45%, relative standard deviations were not more than 3.26%. The results showed as following: Only kaempferol was not detected in the initial fermentation broth. The changes module of different phenolic acid contents in the ferment broth of “Gui-pu No.1” during fermentation process at 22 ℃ and 28 ℃ were different. In contrast the declining trend of polydatin and chlorogenic acid during fermentation process, the changes of other phenolic compounds showed as a trend of increasing first and then decreasing. The variation trends of same compound at different fermentation temperature of 22 ℃ and 28 ℃ were basically the same, but the variation magnitudes were different. In the fermentation broths at 22 ℃ and 28 ℃ for 15 d, only the contents of cyandin-3-O-glucoside, kaempferol and ferulic acid were all higher than those in the initial fermentation broths. This study provided effective quality controlling means and preliminary data support for the quality production of phenolic compounds in Vitis quinnquangularis Rehd winemaking.
2021, 42(21): 311-318.
DOI: 10.13386/j.issn1002-0306.2021020125
Abstract：
In order to provide theoretical support for high value processing and utilization of velvet antler, the differences of physicochemical indexes in velvet antler products by vacuum freeze-drying and boiled water-drying were studied. Three pairs of fresh velvet antlers, one was processed by vacuum freeze-drying method, the other by boiled water-drying method, and the determination of the two products of moisture, crude protein, crude fat and other nutrients and fatty acids, amino acids, cholesterol and mineral elements in 49 indicators, and principal component analysis and cluster analysis were carried out. The results showed that the contents of fatty acid and amino acid in vacuum freeze-dried antler velvet were significantly higher (P<0.01) than boiled-water dried antler velvet, which were (146.48±10.53) mg/100 g and (34.11±0.98) mg/100 g. While the moisture contents of vacuum freeze-dried antler velvet and boiled-water dried antler velvet were (5.37±0.12) mg/100 g and (11.20±1.11) mg/100 g, with significant difference (P<0.01). In the principal component analysis, the cumulative contribution rate of the first three principal components was 80.87%. The samples of boiled-water dried antler velvet and vacuum freeze-dried antler velvet were obviously separated, which indicated that there were significant differences between the two groups. Cluster analysis clustered 16 components with significant differences into 2 groups, it was found that the indexes of velvet antler after drying were significantly different between the two processing techniques. 8 kinds of fatty acids and 7 kinds of amino acids were abundant in vacuum freeze-dried antler velvet. Multivariate statistical analysis method can more intuitively represent the differences of antler components and their advantages and disadvantages in different processing techniques, and vacuum freeze-drying technology can better retain the active ingredients, and provide a direction for velvet antler processing.
In order to provide theoretical support for high value processing and utilization of velvet antler, the differences of physicochemical indexes in velvet antler products by vacuum freeze-drying and boiled water-drying were studied. Three pairs of fresh velvet antlers, one was processed by vacuum freeze-drying method, the other by boiled water-drying method, and the determination of the two products of moisture, crude protein, crude fat and other nutrients and fatty acids, amino acids, cholesterol and mineral elements in 49 indicators, and principal component analysis and cluster analysis were carried out. The results showed that the contents of fatty acid and amino acid in vacuum freeze-dried antler velvet were significantly higher (P<0.01) than boiled-water dried antler velvet, which were (146.48±10.53) mg/100 g and (34.11±0.98) mg/100 g. While the moisture contents of vacuum freeze-dried antler velvet and boiled-water dried antler velvet were (5.37±0.12) mg/100 g and (11.20±1.11) mg/100 g, with significant difference (P<0.01). In the principal component analysis, the cumulative contribution rate of the first three principal components was 80.87%. The samples of boiled-water dried antler velvet and vacuum freeze-dried antler velvet were obviously separated, which indicated that there were significant differences between the two groups. Cluster analysis clustered 16 components with significant differences into 2 groups, it was found that the indexes of velvet antler after drying were significantly different between the two processing techniques. 8 kinds of fatty acids and 7 kinds of amino acids were abundant in vacuum freeze-dried antler velvet. Multivariate statistical analysis method can more intuitively represent the differences of antler components and their advantages and disadvantages in different processing techniques, and vacuum freeze-drying technology can better retain the active ingredients, and provide a direction for velvet antler processing.
2021, 42(21): 319-324.
DOI: 10.13386/j.issn1002-0306.2021020093
Abstract：
In order to investigate the water migration of winter jujube during low temperature (4 ℃) storage, LF-NMR and its imaging technology were used to monitor the transverse relaxation time and image the water distribution of the samples stored within 60 days. At the same time, the appearance change, color, weight loss rate, hardness and respiration intensity of the samples were determined. The results showed that with the passing of storage time, the content of free water in the winter jujube decreased greatly, and gradually permeated to the direction of the fruit core, and transformed into water that was not easy to flow and bound water. The fruit epidermis changed from green to dark red at 32 d, and the weight loss rate increased linearly and reached 2.23% at 40 d. Fruits continue to softening, and the hardness value dropped by nearly half. In addition, winter jujube is a respiratory climacteric fruit, and its respiration intensity reached its peak at 40 days under 4 ℃ environment. The results showed that the migration and loss of water in fruits were accompanied by the decline of related quality physical and chemical indexes. In this study, low-field NMR technology was applied to the quality monitoring of fruits and vegetables, which provided a certain degree of reference for the direction of fruit and vegetable preservation.
In order to investigate the water migration of winter jujube during low temperature (4 ℃) storage, LF-NMR and its imaging technology were used to monitor the transverse relaxation time and image the water distribution of the samples stored within 60 days. At the same time, the appearance change, color, weight loss rate, hardness and respiration intensity of the samples were determined. The results showed that with the passing of storage time, the content of free water in the winter jujube decreased greatly, and gradually permeated to the direction of the fruit core, and transformed into water that was not easy to flow and bound water. The fruit epidermis changed from green to dark red at 32 d, and the weight loss rate increased linearly and reached 2.23% at 40 d. Fruits continue to softening, and the hardness value dropped by nearly half. In addition, winter jujube is a respiratory climacteric fruit, and its respiration intensity reached its peak at 40 days under 4 ℃ environment. The results showed that the migration and loss of water in fruits were accompanied by the decline of related quality physical and chemical indexes. In this study, low-field NMR technology was applied to the quality monitoring of fruits and vegetables, which provided a certain degree of reference for the direction of fruit and vegetable preservation.
2021, 42(21): 325-333.
DOI: 10.13386/j.issn1002-0306.2021020123
Abstract：
The effect of combined treatments of 75 μL/L 1-Methylcyclopropene (1-MCP) combined with two different thicknesses (30, 45 μm) of polyvinyl chloride (PVC) packaging on the storage quality of tumorous stem mustard were investigated at 4 ℃. The results showed that, after 60 days of storage, the firmness of 75 μL/L 1-MCP combined with two different thicknesses of PVC (30 and 45 μm) -treated tumorous stem mustard was 312.13% and 266.72% higher than that of the control group, and the aging index was 50.00% and 25.00% lower than that of the control group, maintaining a high commodity rate; the chlorophyll content was 82.48% and 89.31% higher than that of the control group, and the total amount of free amino acids was lower than that of the control group; The activity of peroxidase (POD) in fresh tissue was 64.29% and 51.23% lower than the control group, and the activity of POD in the peel tissue was 73.47% and 49.88% lower than the control group; the activity of phenylalamine ammonia lyase (PAL) in the fresh tissue was 10.60% and 10.44% lower than the control group, and the activity of PAL in the peel tissue was lower than that of the control group by 71.23% and 64.86%, and inhibited the accumulation of the crude fiber of tumorous stem mustard. This research can provide certain technical guidance and theoretical reference for the storage and preservation of tumorous stem mustard.
The effect of combined treatments of 75 μL/L 1-Methylcyclopropene (1-MCP) combined with two different thicknesses (30, 45 μm) of polyvinyl chloride (PVC) packaging on the storage quality of tumorous stem mustard were investigated at 4 ℃. The results showed that, after 60 days of storage, the firmness of 75 μL/L 1-MCP combined with two different thicknesses of PVC (30 and 45 μm) -treated tumorous stem mustard was 312.13% and 266.72% higher than that of the control group, and the aging index was 50.00% and 25.00% lower than that of the control group, maintaining a high commodity rate; the chlorophyll content was 82.48% and 89.31% higher than that of the control group, and the total amount of free amino acids was lower than that of the control group; The activity of peroxidase (POD) in fresh tissue was 64.29% and 51.23% lower than the control group, and the activity of POD in the peel tissue was 73.47% and 49.88% lower than the control group; the activity of phenylalamine ammonia lyase (PAL) in the fresh tissue was 10.60% and 10.44% lower than the control group, and the activity of PAL in the peel tissue was lower than that of the control group by 71.23% and 64.86%, and inhibited the accumulation of the crude fiber of tumorous stem mustard. This research can provide certain technical guidance and theoretical reference for the storage and preservation of tumorous stem mustard.
2021, 42(21): 334-343.
DOI: 10.13386/j.issn1002-0306.2021030049
Abstract：
In order to explore the influence of different processing technology on marinated beef quality, with marinated beef used as the raw material. The normal temperature storage was used as the control group, and 4 ℃ storage, ultra-high pressure treatment, ultra-high pressure combined with 4 ℃ were used as the treatment group, which provided a reference for providing a new way of marinated beef preservation. The results showed that the sensory scores of marinated beef treated at 4 ℃ storage, ultra-high pressure treatment and ultra-high pressure combined with 4 ℃ were all higher than those of the control group. After 16 days of storage, the changing trends of texture, total volatile base nitrogen (TVB-N) values, pH value, thiobarbituric acid (TBA) values and other indexes were slower than those of the control group. The TVB-N value of the ultra-high pressure combined with 4 ℃ treatment group was 15.254 mg/kg, and the TBA value increased by only 5%. The total viable counts of marinated beef were 1.78 lg CFU/g, while it reached 5.21 lg CFU/g in the normal temperature control group on the 8th day. The electronic nose analyses showed that there was no significant change in odour in the ultra-high pressure combined with 4 ℃ treatment group. After 16 days of storage, its indexes were still close to 0 days. Compared with other treatment groups, ultra-high pressure combined with 4 ℃ treatment can better prolong the storage period of marinated beef. In conclusion, ultra-high pressure combined with 4 ℃ treatment group is the optimal pretreatment method for marinated beef storage.
In order to explore the influence of different processing technology on marinated beef quality, with marinated beef used as the raw material. The normal temperature storage was used as the control group, and 4 ℃ storage, ultra-high pressure treatment, ultra-high pressure combined with 4 ℃ were used as the treatment group, which provided a reference for providing a new way of marinated beef preservation. The results showed that the sensory scores of marinated beef treated at 4 ℃ storage, ultra-high pressure treatment and ultra-high pressure combined with 4 ℃ were all higher than those of the control group. After 16 days of storage, the changing trends of texture, total volatile base nitrogen (TVB-N) values, pH value, thiobarbituric acid (TBA) values and other indexes were slower than those of the control group. The TVB-N value of the ultra-high pressure combined with 4 ℃ treatment group was 15.254 mg/kg, and the TBA value increased by only 5%. The total viable counts of marinated beef were 1.78 lg CFU/g, while it reached 5.21 lg CFU/g in the normal temperature control group on the 8th day. The electronic nose analyses showed that there was no significant change in odour in the ultra-high pressure combined with 4 ℃ treatment group. After 16 days of storage, its indexes were still close to 0 days. Compared with other treatment groups, ultra-high pressure combined with 4 ℃ treatment can better prolong the storage period of marinated beef. In conclusion, ultra-high pressure combined with 4 ℃ treatment group is the optimal pretreatment method for marinated beef storage.
Abstract：
Using Guizhou local variety“Luobie”cherry as the test material, and the primary metabolites as well as fruit softening-related enzyme activities during fruit development were quantified, subsequently, the characteristics of the accumulation of sugar and acid components during fruit development and the changes in fruit softening-related enzyme activities and their relationships were carried out. The results showed that the sugar accumulation of “Luobie” cherry at different stages of fruit development was dominated by the two reducing sugars of glucose and fructose, accounted for 79.17%~88.23% of the total sugar content, the malic acid content accounted for more than 98% of the total acid, which was a typical hexose accumulation type and malic fruit type. The content of propectin was higher in the early stage of fruit development of “Luobie” cherry. With the development of the fruit, the activities of pectin lyase and polygalacturonase first increased and then gradually decreased during the fruit development stage. The activity reached the highest value, and then the activity was significantly reduced (P<0.05) during the color transition period. Pectin lyase and polygalacturonase promoted the degradation of propectin, which made the protopectin content in the fruit significantly decrease and the soluble pectin content significantly increase (P<0.05). In the process of fruit development, the activities of α-amylase and β-amylase first increased and then decreased, which hydrolyzed starch into reducing sugars, so that the starch content gradually decreased. Aldehydes were the most abundant substances in the aroma components of cherry fruits. Among them, the richer content was 3-hexanal, and the richness continued to decrease with the development of the fruit. The rich tasty amino acid (aspartic acid, glutamic acid) played a role in the cherry flavor and quality.
Using Guizhou local variety“Luobie”cherry as the test material, and the primary metabolites as well as fruit softening-related enzyme activities during fruit development were quantified, subsequently, the characteristics of the accumulation of sugar and acid components during fruit development and the changes in fruit softening-related enzyme activities and their relationships were carried out. The results showed that the sugar accumulation of “Luobie” cherry at different stages of fruit development was dominated by the two reducing sugars of glucose and fructose, accounted for 79.17%~88.23% of the total sugar content, the malic acid content accounted for more than 98% of the total acid, which was a typical hexose accumulation type and malic fruit type. The content of propectin was higher in the early stage of fruit development of “Luobie” cherry. With the development of the fruit, the activities of pectin lyase and polygalacturonase first increased and then gradually decreased during the fruit development stage. The activity reached the highest value, and then the activity was significantly reduced (P<0.05) during the color transition period. Pectin lyase and polygalacturonase promoted the degradation of propectin, which made the protopectin content in the fruit significantly decrease and the soluble pectin content significantly increase (P<0.05). In the process of fruit development, the activities of α-amylase and β-amylase first increased and then decreased, which hydrolyzed starch into reducing sugars, so that the starch content gradually decreased. Aldehydes were the most abundant substances in the aroma components of cherry fruits. Among them, the richer content was 3-hexanal, and the richness continued to decrease with the development of the fruit. The rich tasty amino acid (aspartic acid, glutamic acid) played a role in the cherry flavor and quality.
2021, 42(21): 353-360.
DOI: 10.13386/j.issn1002-0306.2020110125
Abstract：
Objective:To study the protective mechanism of Epimedium alkaloids against cyclophosphamide induced reproductive injury in male mice. Methods: First, 40 male mice of Kunming species were randomly divided into blank group and Epimedium low, medium and high dose groups to investigate whether Epimedium alkaloid had reproductive toxicity to male mice. Secondly, another 40 Kunming male mice were injected with cyclophosphamide for modeling, and randomly divided into cyclophosphamide group, cyclophosphamide-alkaloid low, medium and high dose groups. After successful modeling, the mice in each dose group were given the drug for 30 days by gavage except the cyclophosphamide group. After the last administration, mice were sacrificed and the quality of epididymis, testis and sperm of different groups of mice were measured. The contents of superoxide dismutase (SOD), malondialdehyde (MDA), testosterone and Bcl-2/Bax protein in testicular tissue were detected. Results: Epimedium alkaloid had no reproductive toxicity on male mice. Spermatozoa quality and testicular activity decreased significantly after injection of cyclophosphamide, and testicular tissue of mice was seriously damaged, which proved the success of modeling. Compared with the cyclophosphamide group, epididymal coefficient and testicular coefficient of mice in each dose group were significantly increased, sperm number increased, sperm viability increased, sperm malformation rate decreased, SOD activity in testicular tissue increased, MDA content decreased, testosterone level increased, and Bcl-2 /Bax protein ratio increased. Through the observation of testicular tissue section, the damage of testicular tissue was reduced. Conclusion: Epimedium alkaloid can protect the reproductive system of male mice to some extent.
Objective:To study the protective mechanism of Epimedium alkaloids against cyclophosphamide induced reproductive injury in male mice. Methods: First, 40 male mice of Kunming species were randomly divided into blank group and Epimedium low, medium and high dose groups to investigate whether Epimedium alkaloid had reproductive toxicity to male mice. Secondly, another 40 Kunming male mice were injected with cyclophosphamide for modeling, and randomly divided into cyclophosphamide group, cyclophosphamide-alkaloid low, medium and high dose groups. After successful modeling, the mice in each dose group were given the drug for 30 days by gavage except the cyclophosphamide group. After the last administration, mice were sacrificed and the quality of epididymis, testis and sperm of different groups of mice were measured. The contents of superoxide dismutase (SOD), malondialdehyde (MDA), testosterone and Bcl-2/Bax protein in testicular tissue were detected. Results: Epimedium alkaloid had no reproductive toxicity on male mice. Spermatozoa quality and testicular activity decreased significantly after injection of cyclophosphamide, and testicular tissue of mice was seriously damaged, which proved the success of modeling. Compared with the cyclophosphamide group, epididymal coefficient and testicular coefficient of mice in each dose group were significantly increased, sperm number increased, sperm viability increased, sperm malformation rate decreased, SOD activity in testicular tissue increased, MDA content decreased, testosterone level increased, and Bcl-2 /Bax protein ratio increased. Through the observation of testicular tissue section, the damage of testicular tissue was reduced. Conclusion: Epimedium alkaloid can protect the reproductive system of male mice to some extent.
Abstract：
To investigate the efficacy of Liupao tea on regulating phlegm-dampness constitution in sub-health state and the mechanism, a randomized, controlled clinical trial of 90-day was taken using Liupao fresh and aged tea with the intervention dose of 10 g soaked in boiling water of 200 ml for 2 min, twice a day as the intervention means. Traditional Chinese medicine diagnostic indexes and blood biochemical indexes related to phlegm-dampness were recorded before and after intervention, and the change of intestinal flora was analyzed. The results indicated that the phlegm-dampness quality translation score showed a decreasing trend in the middle and end of the intervention among the fresh tea intervention group and aged tea intervention group. The ANOVA results showed the phlegm-dampness quality translation score of fresh tea intervention group had significant differences at three time points of 25, 45 and 90 d after intervention (P<0.05). The intervention of Liupao tea could improve the phlegm-dampness constitution slowly and the effect of fresh tea was slightly faster. Biochemical results showed that Liupao tea had the effect of reducing bilirubin (total bilirubin and direct bilirubin). The effect of aged tea was obvious and the difference was statistically significant (P<0.05). Intestinal flora results showed that the level of Bacterioidetes decreased to 0.49±0.17 in fresh tea intervention group and 0.48±0.35 in aged tea intervention group, while the level of Firmicutes increased to 0.42±0.23 in fresh tea intervention group and 0.45±0.08 in aged tea intervention group after intervention. The relative abundance of Bilophila increased to 0.0024±0.0013 in fresh tea intervention group and 0.0022±0.0034 in aged tea intervention group. Liupao tea changed the relative proportion of Firmicutes and Bacteroidetes in the intestinal flora, promoted the increase of Bilophila, thus Liupao tea may improve the metabolism of blood bilirubin by regulating the bile acid pathway. The relative abundance of Sutterella, Izimaplasmatales and Ruminococcus, which are related to metabolic diseases and energy metabolism, were changed during the experiment. Therefore, Liupao tea may improve the metabolic state of sub-health people by regulating intestinal microbiota.
To investigate the efficacy of Liupao tea on regulating phlegm-dampness constitution in sub-health state and the mechanism, a randomized, controlled clinical trial of 90-day was taken using Liupao fresh and aged tea with the intervention dose of 10 g soaked in boiling water of 200 ml for 2 min, twice a day as the intervention means. Traditional Chinese medicine diagnostic indexes and blood biochemical indexes related to phlegm-dampness were recorded before and after intervention, and the change of intestinal flora was analyzed. The results indicated that the phlegm-dampness quality translation score showed a decreasing trend in the middle and end of the intervention among the fresh tea intervention group and aged tea intervention group. The ANOVA results showed the phlegm-dampness quality translation score of fresh tea intervention group had significant differences at three time points of 25, 45 and 90 d after intervention (P<0.05). The intervention of Liupao tea could improve the phlegm-dampness constitution slowly and the effect of fresh tea was slightly faster. Biochemical results showed that Liupao tea had the effect of reducing bilirubin (total bilirubin and direct bilirubin). The effect of aged tea was obvious and the difference was statistically significant (P<0.05). Intestinal flora results showed that the level of Bacterioidetes decreased to 0.49±0.17 in fresh tea intervention group and 0.48±0.35 in aged tea intervention group, while the level of Firmicutes increased to 0.42±0.23 in fresh tea intervention group and 0.45±0.08 in aged tea intervention group after intervention. The relative abundance of Bilophila increased to 0.0024±0.0013 in fresh tea intervention group and 0.0022±0.0034 in aged tea intervention group. Liupao tea changed the relative proportion of Firmicutes and Bacteroidetes in the intestinal flora, promoted the increase of Bilophila, thus Liupao tea may improve the metabolism of blood bilirubin by regulating the bile acid pathway. The relative abundance of Sutterella, Izimaplasmatales and Ruminococcus, which are related to metabolic diseases and energy metabolism, were changed during the experiment. Therefore, Liupao tea may improve the metabolic state of sub-health people by regulating intestinal microbiota.
2021, 42(21): 370-376.
DOI: 10.13386/j.issn1002-0306.2020120123
Abstract：
In order to explore the anti-alcohol mechanism of vinegar egg liquid on mice after acute alcoholism at different gavage doses and gavage times, blood alcohol concentration was determined by gas chromatography, and activity of alcohol dehydrogenase (ADH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also determined. Moreover, the structures of vinegar egg liquid were identified, aiming to explore the active factors that exert the functions of sobering. The results showed that when 54 mL/kg of vinegar egg liquid was given to the stomach (1 bottle) 15 minutes after alcohol gavage, the sobering effect was the best, and the blood alcohol clearance rate was 21.33%. The blood alcohol clearance rate of mice fed with vinegar egg liquid was higher than that of other three groups at the same dose (54 mL/kg), indicating that the rate of vinegar egg liquid was better than apple cider vinegar, yogurt, and "Neptune Golden Bottle". The serum ADH activity of mice gavaged with vinegar egg liquid was significantly higher than that of the model group, yogurt group and "Neptune Golden Bottle" group (P<0.05), while the liver ALT and AST activities were significantly higher than those of the "Neptune Golden Bottle" group (P<0.05). Structural identification analysis showed that most of its structural sequence contained hydrophobic amino acids such as Leu, Phe, Ala and a large number of structural units, such as Ala, Leu and Leu cluster (Leu-Leu). The vinegar egg liquid can activate ADH and has good sobering activity, which may be related to the hydrophobic short peptides, short peptides containing Ala and Leu, and the Leu cluster short peptides in the vinegar-egg liquid.
In order to explore the anti-alcohol mechanism of vinegar egg liquid on mice after acute alcoholism at different gavage doses and gavage times, blood alcohol concentration was determined by gas chromatography, and activity of alcohol dehydrogenase (ADH), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were also determined. Moreover, the structures of vinegar egg liquid were identified, aiming to explore the active factors that exert the functions of sobering. The results showed that when 54 mL/kg of vinegar egg liquid was given to the stomach (1 bottle) 15 minutes after alcohol gavage, the sobering effect was the best, and the blood alcohol clearance rate was 21.33%. The blood alcohol clearance rate of mice fed with vinegar egg liquid was higher than that of other three groups at the same dose (54 mL/kg), indicating that the rate of vinegar egg liquid was better than apple cider vinegar, yogurt, and "Neptune Golden Bottle". The serum ADH activity of mice gavaged with vinegar egg liquid was significantly higher than that of the model group, yogurt group and "Neptune Golden Bottle" group (P<0.05), while the liver ALT and AST activities were significantly higher than those of the "Neptune Golden Bottle" group (P<0.05). Structural identification analysis showed that most of its structural sequence contained hydrophobic amino acids such as Leu, Phe, Ala and a large number of structural units, such as Ala, Leu and Leu cluster (Leu-Leu). The vinegar egg liquid can activate ADH and has good sobering activity, which may be related to the hydrophobic short peptides, short peptides containing Ala and Leu, and the Leu cluster short peptides in the vinegar-egg liquid.
2021, 42(21): 377-384.
DOI: 10.13386/j.issn1002-0306.2020120149
Abstract：
In order to explore the effect of high sucrose diet on the development, life span and antioxidant capacity ofD. melanogaster, life span, locomotion capacity and antioxidant ability of D. melanogaster were measured through feeding high sucrose-diets to D. melanogaster. At the same time, transcriptome sequencing of high sucrose D. melanogaster was performed to find out the mechanism that high sucrose affected the development of D. melanogaster at the gene transcription level. The results showed that compared with the control group, the average life span of female flies, male flies and mixed flies was shortened by 35.01%、43.01% and 34.15%, respectively in the high-sucrose group. The survival curve of male D. melanogaster and mixed D. melanogaster were significantly shortened than that of the control group（P<0.05）. Compared with the control group, high sucrose diet reduced pupation rate, eclosion rate and climbing ability of flies. In the high-sucrose group, T-SOD activities and CAT activities were decreased in male D. melanogaster, while MDA content was increased. In addition, through transcriptome sequencing, we found that the differentially expressed genes of the high-sugar group flies were enriched in the development process, the regulation of metabolic activities, and the stress response of flies. This study showed that high sucrose diet could significantly reduce the life span, development, locomotion capacity and antioxidant capacity of D. melanogaster, it would provide reference for healthy diet.
In order to explore the effect of high sucrose diet on the development, life span and antioxidant capacity of
2021, 42(21): 385-391.
DOI: 10.13386/j.issn1002-0306.2020120278
Abstract：
Holothurin A (HA) and Echinoside A (EA) are two major saponins in sea cucumbers. In the present study, the effects of HA and EA on uric acid metabolism were evaluated by determining the level of serum uric acid, the activity of uric acid metabolism-related enzymes and the mRNA expression of renal transporters in db/db mice. The db/db mice were divided into 3 groups (n=8), including model, HA and EA groups, according to the body weight. C57/BL6 mice was used as the control group. The mice in HA and EA groups were supplemented with 0.07% HA and EA for 2 weeks, respectively. Results showed that the mice in the model group showed a significant increase in serum uric acid levels compared with the control group. Dietary intervention with HA and EA significantly reduced the serum uric acid level by 12.7% and 18.1%, respectively(P<0.05), and significantly alleviated the pathological changes of renal tissue represented by glomeruli. Mechanism studies showed that no significant difference was observed in the activities of liver xanthine oxidase and adenosine deaminase among the four groups(P>0.05). The mRNA expression of transporters, including GLUT9, OAT1, OCTs and OCTNs, were significantly elevated after administration with HA and EA(P<0.05). HA and EA may alleviate hyperuricemia by regulating the mRNA expression of renal uric acid metabolism-related transporters, in which EA is better than the HA. The obtained results may provide theoretical basis for dietary sea cucumber saponins to prevent abnormal uric acid metabolism.
Holothurin A (HA) and Echinoside A (EA) are two major saponins in sea cucumbers. In the present study, the effects of HA and EA on uric acid metabolism were evaluated by determining the level of serum uric acid, the activity of uric acid metabolism-related enzymes and the mRNA expression of renal transporters in db/db mice. The db/db mice were divided into 3 groups (n=8), including model, HA and EA groups, according to the body weight. C57/BL6 mice was used as the control group. The mice in HA and EA groups were supplemented with 0.07% HA and EA for 2 weeks, respectively. Results showed that the mice in the model group showed a significant increase in serum uric acid levels compared with the control group. Dietary intervention with HA and EA significantly reduced the serum uric acid level by 12.7% and 18.1%, respectively(P<0.05), and significantly alleviated the pathological changes of renal tissue represented by glomeruli. Mechanism studies showed that no significant difference was observed in the activities of liver xanthine oxidase and adenosine deaminase among the four groups(P>0.05). The mRNA expression of transporters, including GLUT9, OAT1, OCTs and OCTNs, were significantly elevated after administration with HA and EA(P<0.05). HA and EA may alleviate hyperuricemia by regulating the mRNA expression of renal uric acid metabolism-related transporters, in which EA is better than the HA. The obtained results may provide theoretical basis for dietary sea cucumber saponins to prevent abnormal uric acid metabolism.
2021, 42(21): 392-399.
DOI: 10.13386/j.issn1002-0306.2021010175
Abstract：
To explore the effect of the crude extraction from distiller's grains on the proliferation and apoptosis of human hepatocellular carcinoma cell HepG2, the crude extraction from distiller's grains were analyzed by LC-MS firstly, then used to treat HepG2 cells by different concentrations. RTCA was used to detect its effects on proliferation of HepG2 cells. Flow cytometry was used to detect its effects on the cycle of HepG2 cells. Real-Time qPCR was used to detect its effects on apoptosis of HepG2 cells. Western Blot was used to detect the expression of apoptotic-related protein. 43 substances in the crude extraction from distiller's grains were determined by LC-MS. The proliferation of HepG2 cells were significantly inhibited by the crude extraction from distiller's grains and presented concentration dependent; The crude extraction from distiller's grains significantly down-regulated the expression of mRNA and protein of S phase CyclinA and its kinase CDK2, reduced the expression of mRNA and protein of Bcl-2 and increased the expression of mRNA and protein of Bax (P<0.05); the expression levels of CYTC, Cleaved-Caspase-9 and Cleaved-Caspase-3 were increased gradually (P<0.05), the expression levels of Caspase-9, Caspase-3 were decreased (P<0.05). The results showed that the crude extraction from distiller's grains that contained a variety of active substances can significantly inhibit the proliferation of HepG2 cells and may induce apoptosis of HepG2 cells by activating the apoptotic mitochondrial pathway.
To explore the effect of the crude extraction from distiller's grains on the proliferation and apoptosis of human hepatocellular carcinoma cell HepG2, the crude extraction from distiller's grains were analyzed by LC-MS firstly, then used to treat HepG2 cells by different concentrations. RTCA was used to detect its effects on proliferation of HepG2 cells. Flow cytometry was used to detect its effects on the cycle of HepG2 cells. Real-Time qPCR was used to detect its effects on apoptosis of HepG2 cells. Western Blot was used to detect the expression of apoptotic-related protein. 43 substances in the crude extraction from distiller's grains were determined by LC-MS. The proliferation of HepG2 cells were significantly inhibited by the crude extraction from distiller's grains and presented concentration dependent; The crude extraction from distiller's grains significantly down-regulated the expression of mRNA and protein of S phase CyclinA and its kinase CDK2, reduced the expression of mRNA and protein of Bcl-2 and increased the expression of mRNA and protein of Bax (P<0.05); the expression levels of CYTC, Cleaved-Caspase-9 and Cleaved-Caspase-3 were increased gradually (P<0.05), the expression levels of Caspase-9, Caspase-3 were decreased (P<0.05). The results showed that the crude extraction from distiller's grains that contained a variety of active substances can significantly inhibit the proliferation of HepG2 cells and may induce apoptosis of HepG2 cells by activating the apoptotic mitochondrial pathway.
2021, 42(21): 400-407.
DOI: 10.13386/j.issn1002-0306.2020080268
Abstract：
Phenolic compounds are important components in plant food, and they have various functional activities. However, due to their low bioavailability, they cannot fully exert their biological activities in vivo. Therefore, it is necessary to find an effective way to improve its bioavailability. This article reviews the effects of three food matrices, polysaccharides, proteins, and lipids, and different processing methods on the bioavailability of polyphenols, in order to provide references and considerations for improving the bioavailability of polyphenols in food processing.
Phenolic compounds are important components in plant food, and they have various functional activities. However, due to their low bioavailability, they cannot fully exert their biological activities in vivo. Therefore, it is necessary to find an effective way to improve its bioavailability. This article reviews the effects of three food matrices, polysaccharides, proteins, and lipids, and different processing methods on the bioavailability of polyphenols, in order to provide references and considerations for improving the bioavailability of polyphenols in food processing.
2021, 42(21): 408-413.
DOI: 10.13386/j.issn1002-0306.2020090276
Abstract：
The sensory and nutritional quality of starch-based foods depends on the changes of structure (granular and molecular structures) and physicochemical properties (gelatinization, rheological and digestion properties) of starch during processing. Milk protein can absorb on the surface of starch granule through hydrophobic interaction, thus inhibiting its water absorption capacity and accessibility to amylase; moreover, it can alter the rheological properties of starch by entangling with starch chains to form a strong or weak (phase separation) gel under the combined action of electrostatic interaction, hydrogen bond, and hydrophobic interaction. This article reviews the recent researches on the interactions between starch and milk protein as well as the effects of milk protein on the thermal, rheological, and digestion properties of starch, which classifies the mechanism on the interactions between starch and milk protein and provides a theoretical guide for using milk protein to improving the processing performance, sensory and nutritional quality of starch-based foods.
The sensory and nutritional quality of starch-based foods depends on the changes of structure (granular and molecular structures) and physicochemical properties (gelatinization, rheological and digestion properties) of starch during processing. Milk protein can absorb on the surface of starch granule through hydrophobic interaction, thus inhibiting its water absorption capacity and accessibility to amylase; moreover, it can alter the rheological properties of starch by entangling with starch chains to form a strong or weak (phase separation) gel under the combined action of electrostatic interaction, hydrogen bond, and hydrophobic interaction. This article reviews the recent researches on the interactions between starch and milk protein as well as the effects of milk protein on the thermal, rheological, and digestion properties of starch, which classifies the mechanism on the interactions between starch and milk protein and provides a theoretical guide for using milk protein to improving the processing performance, sensory and nutritional quality of starch-based foods.
2021, 42(21): 414-419.
DOI: 10.13386/j.issn1002-0306.2020090301
Abstract：
In recent years, allergies caused by consumption of aquatic products are increasing, due to a spurt processing in consumption of aquatic products. Food allergy is an important public health issue around the world. Therefore, the hypoallergenic or non-allergenic food by processed technology is of critical significance to allergic people. The research progress of aquatic products allergen processing and reduction technology are summarized in this article. The main types of aquatic product allergens and details of different food processing technologies effects on aquatic products allergens are introduced. The hypoallergenic aquatic products research status and development trends are analyzed in order to provide guidance for the future research.
In recent years, allergies caused by consumption of aquatic products are increasing, due to a spurt processing in consumption of aquatic products. Food allergy is an important public health issue around the world. Therefore, the hypoallergenic or non-allergenic food by processed technology is of critical significance to allergic people. The research progress of aquatic products allergen processing and reduction technology are summarized in this article. The main types of aquatic product allergens and details of different food processing technologies effects on aquatic products allergens are introduced. The hypoallergenic aquatic products research status and development trends are analyzed in order to provide guidance for the future research.
2021, 42(21): 420-427.
DOI: 10.13386/j.issn1002-0306.2020090316
Abstract：
Soybean saponins are a kind of triterpenoid compound, which are secondary metabolites during the growth of soybeans, and mainly exist in cotyledons and hypocotyls of soybean seeds. Studies show that soybean saponins have a variety of biological activities, including antiviral, antitumor, obesity prevention and immune regulation. In this paper, the structure of soybean saponin monomer is listed, the physicochemical properties of soyabean saponin are introduced, and the factors affecting the content of soybean saponin are analyzed. Because of the different soybean varieties, planting environment and analysis methods, the content of soybean saponin is different. At present, the commonly used extraction methods of soybean saponins are solvent method, macroporous adsorption resin hair, chromatography separation, microwave extraction and ultrasonic extraction are also often used for auxiliary extraction of soybean saponins. The common detection methods of soybean saponins include spectrophotometry, thin layer chromatography, liquid chromatography, liquid chromatography tandem mass spectrometry and colorimetry. Because of its unique physical and chemical properties and biological activities, soybean saponins are widely used in agriculture, food, medicine, cosmetics and other fields. However, the research and application of soybean saponins are limited because of the difficulty in extraction and purification of soybean saponins. Therefore, it is of great significance to improve the extraction rate of soybean saponins, optimize the extraction methods of soybean saponins, and make full and rational use of soybean saponins resources, which are of great significance for food development and drug development. The aim is to provide reference for the extraction and purification of soybean saponins and its further research.
Soybean saponins are a kind of triterpenoid compound, which are secondary metabolites during the growth of soybeans, and mainly exist in cotyledons and hypocotyls of soybean seeds. Studies show that soybean saponins have a variety of biological activities, including antiviral, antitumor, obesity prevention and immune regulation. In this paper, the structure of soybean saponin monomer is listed, the physicochemical properties of soyabean saponin are introduced, and the factors affecting the content of soybean saponin are analyzed. Because of the different soybean varieties, planting environment and analysis methods, the content of soybean saponin is different. At present, the commonly used extraction methods of soybean saponins are solvent method, macroporous adsorption resin hair, chromatography separation, microwave extraction and ultrasonic extraction are also often used for auxiliary extraction of soybean saponins. The common detection methods of soybean saponins include spectrophotometry, thin layer chromatography, liquid chromatography, liquid chromatography tandem mass spectrometry and colorimetry. Because of its unique physical and chemical properties and biological activities, soybean saponins are widely used in agriculture, food, medicine, cosmetics and other fields. However, the research and application of soybean saponins are limited because of the difficulty in extraction and purification of soybean saponins. Therefore, it is of great significance to improve the extraction rate of soybean saponins, optimize the extraction methods of soybean saponins, and make full and rational use of soybean saponins resources, which are of great significance for food development and drug development. The aim is to provide reference for the extraction and purification of soybean saponins and its further research.
2021, 42(21): 428-434.
DOI: 10.13386/j.issn1002-0306.2020100019
Abstract：
Functional oligosaccharide is a kind of carbohydrates which is not easily absorbed by the gut while can improve intestinal health. In recent years, extensive research has been conducted on the biological activities of functional oligosaccharides, especially on the effects of oligosaccharides on intestinal health. Functional oligosaccharides can provide a good internal environment for intestinal tract. Functional oligosaccharides can promote intestinal absorption of nutrients and mineral elements by increasing digestive enzyme activity, improving intestinal tissue and producing lactic acid. They can also alleviate metabolic syndrome, reduce inflammation, enhance immune response and improve intestinal mucosal barrier by regulating intestinal flora, improving intestinal tissue and increasing the production of short chain fatty acids. The regulatory effects of functional oligosaccharides on intestinal health are reviewed in this paper which can provide theoretical basis for the further development and application of functional oligosaccharides.
Functional oligosaccharide is a kind of carbohydrates which is not easily absorbed by the gut while can improve intestinal health. In recent years, extensive research has been conducted on the biological activities of functional oligosaccharides, especially on the effects of oligosaccharides on intestinal health. Functional oligosaccharides can provide a good internal environment for intestinal tract. Functional oligosaccharides can promote intestinal absorption of nutrients and mineral elements by increasing digestive enzyme activity, improving intestinal tissue and producing lactic acid. They can also alleviate metabolic syndrome, reduce inflammation, enhance immune response and improve intestinal mucosal barrier by regulating intestinal flora, improving intestinal tissue and increasing the production of short chain fatty acids. The regulatory effects of functional oligosaccharides on intestinal health are reviewed in this paper which can provide theoretical basis for the further development and application of functional oligosaccharides.
2021, 42(21): 435-444.
DOI: 10.13386/j.issn1002-0306.2020100030
Abstract：
As a dual-purpose resource of medicine and food, Moringa oleifera leaves are rich in protein, polysaccharide, vitamins, minerals and other nutrients, as well as flavonoids, polyphenols and other active chemical components, which has become a research hotspot in food, feed and medicine industries in recent years. Moringa oleifera leaves have many physiological functions, such as hypoglycemic, antioxidant, anticancer, antibacterial and so on. However, the health food with Moringa oleifera leaves as the effective component are still in the research stage, and its medicinal value needs to be further explored. In this paper, the nutritional composition, physiological activity, function and practical application of Moringa oleifera leaves are reviewed, and the future development in food, medicine and other fields is prospected, in order to provide theoretical basis for more scientific understanding and in-depth study of Moringa oleifera leaves, and provide effective reference for comprehensive utilization of Moringa oleifera leaves.
As a dual-purpose resource of medicine and food, Moringa oleifera leaves are rich in protein, polysaccharide, vitamins, minerals and other nutrients, as well as flavonoids, polyphenols and other active chemical components, which has become a research hotspot in food, feed and medicine industries in recent years. Moringa oleifera leaves have many physiological functions, such as hypoglycemic, antioxidant, anticancer, antibacterial and so on. However, the health food with Moringa oleifera leaves as the effective component are still in the research stage, and its medicinal value needs to be further explored. In this paper, the nutritional composition, physiological activity, function and practical application of Moringa oleifera leaves are reviewed, and the future development in food, medicine and other fields is prospected, in order to provide theoretical basis for more scientific understanding and in-depth study of Moringa oleifera leaves, and provide effective reference for comprehensive utilization of Moringa oleifera leaves.
2021, 42(21): 445-453.
DOI: 10.13386/j.issn1002-0306.2020100037
Abstract：
Astaxanthin is an important secondary carotenoid with extremely strong antioxidative properties and is widely used in food, chemicals, pharmaceuticals, aquacultures and so on. The synthetic methods of astaxanthin include chemical synthesis and biosynthesis. Chemical synthesis of astaxanthin is the source of commercial astaxanthin, while biosynthesis of astaxanthin is safer and more popular in food and health products industries. This review summaries chemical synthetic and biosynthetic pathway of astaxanthin, with emphasizing on the biosynthetic pathways of astaxanthin, key genes involved in biosynthetic and metabolic network of astaxnathin in microorganisms and plants. The research progress of using random mutagenesis, metabolic engineering, enzyme engineering and other methods to improve the synthesis and accumulation of astaxanthin in bacteria, yeast, and marine eukaryotic microorganisms is summarized. This article can provide theoretical guidance for the research on the efficient synthesis of astaxanthin.
Astaxanthin is an important secondary carotenoid with extremely strong antioxidative properties and is widely used in food, chemicals, pharmaceuticals, aquacultures and so on. The synthetic methods of astaxanthin include chemical synthesis and biosynthesis. Chemical synthesis of astaxanthin is the source of commercial astaxanthin, while biosynthesis of astaxanthin is safer and more popular in food and health products industries. This review summaries chemical synthetic and biosynthetic pathway of astaxanthin, with emphasizing on the biosynthetic pathways of astaxanthin, key genes involved in biosynthetic and metabolic network of astaxnathin in microorganisms and plants. The research progress of using random mutagenesis, metabolic engineering, enzyme engineering and other methods to improve the synthesis and accumulation of astaxanthin in bacteria, yeast, and marine eukaryotic microorganisms is summarized. This article can provide theoretical guidance for the research on the efficient synthesis of astaxanthin.
2021, 42(21): 454-463.
DOI: 10.13386/j.issn1002-0306.2020100095
Abstract：
Flavonoids are secondary metabolites of plants, which have a variety of important biological functions and have potential beneficial effects on human health. As antibacterial agents, flavonoids play an important role in the interaction and defense reaction between plants and microorganisms. This article summarizes the biosynthetic pathways and regulation rules of flavonoids, focusing on the effects of external environment such as light, temperature, moisture, radiation, hormones, minerals and transcription factors such as MYB, bHLH, WD40 and NAC on the synthesis of flavonoids. Strengthen research in this area, aiming to provide guidance for the better development and utilization of plant flavonoid functional ingredients.
Flavonoids are secondary metabolites of plants, which have a variety of important biological functions and have potential beneficial effects on human health. As antibacterial agents, flavonoids play an important role in the interaction and defense reaction between plants and microorganisms. This article summarizes the biosynthetic pathways and regulation rules of flavonoids, focusing on the effects of external environment such as light, temperature, moisture, radiation, hormones, minerals and transcription factors such as MYB, bHLH, WD40 and NAC on the synthesis of flavonoids. Strengthen research in this area, aiming to provide guidance for the better development and utilization of plant flavonoid functional ingredients.
2021, 42(21): 464-472.
DOI: 10.13386/j.issn1002-0306.2020100118
Abstract：
Ice slurry can effectively inhibit the growth of endogenous enzymes and microorganisms in aquatic products because of its good fluidity and high cold storage density. It is a hot spot for experts in aquatic products and related fields. This paper summarizes the preparation technology of fluid ice, including method of fluidized bed, vacuum, scraping, supercooling and direct contact. At present, method of scraping and supercooling are widely used in commercial application. In addition, the preparation technology, growth and inhibition conditions, hydrodynamics, thermodynamic characteristics and its application in aquatic products are also explained in this paper. The main problems existing in the application of this technology in aquatic products and improvement suggestions are put forward, which can provide reference for future aquatic product storage and transportation technology and commercial application of ice slurry.
Ice slurry can effectively inhibit the growth of endogenous enzymes and microorganisms in aquatic products because of its good fluidity and high cold storage density. It is a hot spot for experts in aquatic products and related fields. This paper summarizes the preparation technology of fluid ice, including method of fluidized bed, vacuum, scraping, supercooling and direct contact. At present, method of scraping and supercooling are widely used in commercial application. In addition, the preparation technology, growth and inhibition conditions, hydrodynamics, thermodynamic characteristics and its application in aquatic products are also explained in this paper. The main problems existing in the application of this technology in aquatic products and improvement suggestions are put forward, which can provide reference for future aquatic product storage and transportation technology and commercial application of ice slurry.
2021, 42(21): 473-481.
DOI: 10.13386/j.issn1002-0306.2020110088
Abstract：
Radio frequency (RF) is an efficient, uniformity heating method, which can be used for pasteurization and disinfestations. It also shows the superiorities on low-moisture content food heating comparing with microwave (MW) heating. This manuscript describes the mechanism, effect and modeling of RF pasteurization/disinfestations. When low frequency electromagnetic wave is used for heating treatment, the contribution of dipole relaxation to temperature rise decreases, while the proportion of ion conduction increases, and low moisture content food has low thermal conductivity. These factors makes RF heating suitable for sterilization and insecticidal operation of low moisture content food such as grain. In addition, RF frequency electromagnetic wave length makes the heating has better penetration and internal heating uniformity. And the RF system can easily integrate hot air, vacuum, thermal circulation and other heating methods, so as to improve the heating efficiency, enhance the purpose of product quality. In conclusion, RF has great advantages in heating efficiency compared with traditional heating method, which can significantly reduce the loss caused by harmful organisms in grain with low water content, which is of great significance to the preservation of agricultural products. This paper provides the basis and reference for the application of RF technology in the preservation of grain with low water content.
Radio frequency (RF) is an efficient, uniformity heating method, which can be used for pasteurization and disinfestations. It also shows the superiorities on low-moisture content food heating comparing with microwave (MW) heating. This manuscript describes the mechanism, effect and modeling of RF pasteurization/disinfestations. When low frequency electromagnetic wave is used for heating treatment, the contribution of dipole relaxation to temperature rise decreases, while the proportion of ion conduction increases, and low moisture content food has low thermal conductivity. These factors makes RF heating suitable for sterilization and insecticidal operation of low moisture content food such as grain. In addition, RF frequency electromagnetic wave length makes the heating has better penetration and internal heating uniformity. And the RF system can easily integrate hot air, vacuum, thermal circulation and other heating methods, so as to improve the heating efficiency, enhance the purpose of product quality. In conclusion, RF has great advantages in heating efficiency compared with traditional heating method, which can significantly reduce the loss caused by harmful organisms in grain with low water content, which is of great significance to the preservation of agricultural products. This paper provides the basis and reference for the application of RF technology in the preservation of grain with low water content.
