2017 No. 18
Cited By
Abstract：
The rheological properties of protein emulsion system was easy to be changed when it was heated, thus affecting its quality.In order to improve the heat resistance of the emulsion, a new multi-functional emulsion microaggregate was constructed based on the heteroaggregation effect of emulsion.Soybean polysaccharide ( SSPS) and lactoferrin ( LF) as emulsifier, DHA andβ-carotene as functional components were prepared to SSPS-DHA emulsion and LF-β-carotene emulsion. Then, heteroaggregation forming emulsions of different micro-clusters occurred in different proportions. The effects of 25 ~ 80 ℃programmed heating 30 min ( heating process) and 80 ℃ heating 30 min ( simulated pasteurization) on the physical stability and rheological properties of the emulsion were investigated. The results showed that the single LF-β-carotene emulsion was completely denatured and exhibited solid after heating.The rheological properties of the SSPS-DHA/LF-β-carotene emulsion micro-aggregates were significantly improved under heating condition, the fluidity and viscoelastic of the 90 wt% LF-β-carotene-10 wt% SSPS-DHA emulsion micro-aggregates showed fluid characteristics. Therefore, the addition of SSPS-DHA emulsion significantly improved the thermal denaturation and thermal coagulation characteristics of the protein emulsion, thus ensuring that the heat treatment of pasteurization did not change the texture of the functional compound emulsion.
The rheological properties of protein emulsion system was easy to be changed when it was heated, thus affecting its quality.In order to improve the heat resistance of the emulsion, a new multi-functional emulsion microaggregate was constructed based on the heteroaggregation effect of emulsion.Soybean polysaccharide ( SSPS) and lactoferrin ( LF) as emulsifier, DHA andβ-carotene as functional components were prepared to SSPS-DHA emulsion and LF-β-carotene emulsion. Then, heteroaggregation forming emulsions of different micro-clusters occurred in different proportions. The effects of 25 ~ 80 ℃programmed heating 30 min ( heating process) and 80 ℃ heating 30 min ( simulated pasteurization) on the physical stability and rheological properties of the emulsion were investigated. The results showed that the single LF-β-carotene emulsion was completely denatured and exhibited solid after heating.The rheological properties of the SSPS-DHA/LF-β-carotene emulsion micro-aggregates were significantly improved under heating condition, the fluidity and viscoelastic of the 90 wt% LF-β-carotene-10 wt% SSPS-DHA emulsion micro-aggregates showed fluid characteristics. Therefore, the addition of SSPS-DHA emulsion significantly improved the thermal denaturation and thermal coagulation characteristics of the protein emulsion, thus ensuring that the heat treatment of pasteurization did not change the texture of the functional compound emulsion.
Abstract：
The acid soaking pretreatment combined with reduced pressure vacuum technology was applied in the traditional method of brine immersion to produce salted eggs.The physicochemical changes of the salted eggs obtained by the two methods were compared.The results showed that the salinity both egg white and yolk increased faster and the production cycle was shortened from 32 days to 6 days.Compared with the traditional salted eggs, the eggs produced by the new technology showed no significant difference, and meet the standard of salted egg. Over time, the oil exudation of two groups had reached more than16%.The fatty acids and flavor components were analyzed by GC-MS.The results showed that both the two kinds of salted egg yolk contained 13 kinds of fatty acids, of which the components were the same, and the relative contents fluctuated in a small range.While the flavor substances of the salted eggs obtained by the new method were four kinds more than those of the traditional ones.When observed by electron microscope, the surface of eggshell became rough after acid treatment, which was beneficial to the curing process.
The acid soaking pretreatment combined with reduced pressure vacuum technology was applied in the traditional method of brine immersion to produce salted eggs.The physicochemical changes of the salted eggs obtained by the two methods were compared.The results showed that the salinity both egg white and yolk increased faster and the production cycle was shortened from 32 days to 6 days.Compared with the traditional salted eggs, the eggs produced by the new technology showed no significant difference, and meet the standard of salted egg. Over time, the oil exudation of two groups had reached more than16%.The fatty acids and flavor components were analyzed by GC-MS.The results showed that both the two kinds of salted egg yolk contained 13 kinds of fatty acids, of which the components were the same, and the relative contents fluctuated in a small range.While the flavor substances of the salted eggs obtained by the new method were four kinds more than those of the traditional ones.When observed by electron microscope, the surface of eggshell became rough after acid treatment, which was beneficial to the curing process.
Abstract：
Objective: To study on bioative detetion and cell-based absorption mechanisms of gastrointestinal hydrolysis derived from bovine casein. It can further elucidate physiological mechanisms of food protein to humanbeing.Methods: Bovine milk casein was hydrolyzed in vitro simulating gastrointestinal digestion.The hydrolysate's antioxidant and antimicrobial activity were detected through the DPPH free radical clearance rate analysis and the bacteriostatic ring size determination. In addation, Caco-2 monolayer cell model was optimizated and established to simulate the membrane absorption of hydrolysate. RP-HPLC was used to analyze the digestive juices before and after across the membrane.Results: It showed the DPPH free radical clearance rates reached maximum, 46.40% of 2 h-Gastricand 56.7% of 2h-Gastroin-testinal digestions from bovine casein.At the same time, the inhibition activity on Escherichia coli and Staphylococcus aureus also achieve maximum. Experiment results showed that hydrolyzed 2 h stomach simulation peptide absorption nitrogen bioavailability of 7.79%, 2 h hydrolyzed imtestines simulation of 15.11%, after the flat.The peptide can be successfully absorb water into single cell layer under the side, but most hydrophobic peptide by not easily, easy degradation or stop.Conclusion: The gastrointestinal hydrolysate of casein can produce bioactive peptides as well as absorb by intestinal cell monolayer.
Objective: To study on bioative detetion and cell-based absorption mechanisms of gastrointestinal hydrolysis derived from bovine casein. It can further elucidate physiological mechanisms of food protein to humanbeing.Methods: Bovine milk casein was hydrolyzed in vitro simulating gastrointestinal digestion.The hydrolysate's antioxidant and antimicrobial activity were detected through the DPPH free radical clearance rate analysis and the bacteriostatic ring size determination. In addation, Caco-2 monolayer cell model was optimizated and established to simulate the membrane absorption of hydrolysate. RP-HPLC was used to analyze the digestive juices before and after across the membrane.Results: It showed the DPPH free radical clearance rates reached maximum, 46.40% of 2 h-Gastricand 56.7% of 2h-Gastroin-testinal digestions from bovine casein.At the same time, the inhibition activity on Escherichia coli and Staphylococcus aureus also achieve maximum. Experiment results showed that hydrolyzed 2 h stomach simulation peptide absorption nitrogen bioavailability of 7.79%, 2 h hydrolyzed imtestines simulation of 15.11%, after the flat.The peptide can be successfully absorb water into single cell layer under the side, but most hydrophobic peptide by not easily, easy degradation or stop.Conclusion: The gastrointestinal hydrolysate of casein can produce bioactive peptides as well as absorb by intestinal cell monolayer.
Abstract：
The article mainly evaluated the antioxidant ability of total flavonoids in various extracts ( ethyl alcohol, ethyl acetate, normal butyl alcohol, chloroform fraction and water) from Premna microphylla Turcz leaves in Jiangyou area including DPPH radical, ABTS+· radical, hydroxyl radical, superoxide anion radical scavenging effect, reducing power, ferrous ions chelating activities and total antioxidant capacity ( FRAP) . The free radical scavenging activity of total flavonoids extracted by different concentrations of ethanol was highest in DPPH. The free radical scavenging activity ( DPPH radical, ·OH, ABTS+·) , total antioxidant capacity ( FRAP) and reducing power were dependent on the concentration of alcohol increasing first and then decreasing, while the superoxide anion radical scavenging activity was contrary to the increase of alcohol concentration. The comprehensive evaluation index ( APC) of tested samples was decreased in the following order: 75% ethanol extract > 65%ethanol extract > 55% ethanol extract > 85% ethanol extract > 95% ethanol extract. The DPPH radical scavenging activity, FRAP value and reducing power were higher than those of other solvent extracts.The superoxide anion radical scavenging rate of ethyl acetate extract was stronger than those of other solvent extracts. The antioxidant capacity of ethyl acetate extract was strongest according to the APC results.The flavone from leaves of Premna microphylla Turcz has strong antioxidant activity and can be used as antioxidant or raw materials of healthy food.
The article mainly evaluated the antioxidant ability of total flavonoids in various extracts ( ethyl alcohol, ethyl acetate, normal butyl alcohol, chloroform fraction and water) from Premna microphylla Turcz leaves in Jiangyou area including DPPH radical, ABTS+· radical, hydroxyl radical, superoxide anion radical scavenging effect, reducing power, ferrous ions chelating activities and total antioxidant capacity ( FRAP) . The free radical scavenging activity of total flavonoids extracted by different concentrations of ethanol was highest in DPPH. The free radical scavenging activity ( DPPH radical, ·OH, ABTS+·) , total antioxidant capacity ( FRAP) and reducing power were dependent on the concentration of alcohol increasing first and then decreasing, while the superoxide anion radical scavenging activity was contrary to the increase of alcohol concentration. The comprehensive evaluation index ( APC) of tested samples was decreased in the following order: 75% ethanol extract > 65%ethanol extract > 55% ethanol extract > 85% ethanol extract > 95% ethanol extract. The DPPH radical scavenging activity, FRAP value and reducing power were higher than those of other solvent extracts.The superoxide anion radical scavenging rate of ethyl acetate extract was stronger than those of other solvent extracts. The antioxidant capacity of ethyl acetate extract was strongest according to the APC results.The flavone from leaves of Premna microphylla Turcz has strong antioxidant activity and can be used as antioxidant or raw materials of healthy food.
2017, (18): 25-29.
DOI: 10.13386/j.issn1002-0306.2017.18.005
Abstract：
Effect of sesame main components on sesame paste storage stability was researched and the suitability evaluation model of sesame paste processing was established. Ten varieties of sesame were used as the research objects which collected from Henan, Anhui, Hubei province. Correlation analysis was used to investigate of the interrelation among the various components and the storage stability indexes. Results showed that the ash content and crude fat content were positively correlated with the centrifugal oil rate and sedimentation rate, which had a negative effect on the stability of sesame paste.The content of soluble sugar and crude protein had a negative correlation with the centrifugal oil rate and sedimentation oil rate, which had a positive effect on the stability of sesame paste. According to the degree of correlation between the components content and the sesame paste storage stability, there was established the sesame processing suitability evaluation model of sesame main components content.Furthermore, proper processing of sesame top three sesame varieties was calculated as follows:Ezhi No.4, Zheng Taizhi No.13, Wanzhi No.3.
Effect of sesame main components on sesame paste storage stability was researched and the suitability evaluation model of sesame paste processing was established. Ten varieties of sesame were used as the research objects which collected from Henan, Anhui, Hubei province. Correlation analysis was used to investigate of the interrelation among the various components and the storage stability indexes. Results showed that the ash content and crude fat content were positively correlated with the centrifugal oil rate and sedimentation rate, which had a negative effect on the stability of sesame paste.The content of soluble sugar and crude protein had a negative correlation with the centrifugal oil rate and sedimentation oil rate, which had a positive effect on the stability of sesame paste. According to the degree of correlation between the components content and the sesame paste storage stability, there was established the sesame processing suitability evaluation model of sesame main components content.Furthermore, proper processing of sesame top three sesame varieties was calculated as follows:Ezhi No.4, Zheng Taizhi No.13, Wanzhi No.3.
Abstract：
In order to obtain the characteristics of tilapia fillets under osmosis dehydration vacuum-microwave drying conditions, the moisture content and drying rate of fish fillet were carried out during drying process.The effect of different microwave gap ratio, power density and vacuum degree on drying characteristic of fish fillet were determined and the drying kinetics model of osmosis dehydration vacuum-microwave drying was set up.The results showed that the microwave gap ratio, power density and vacuum degree had greater influences on dry characteristics of tilapia fillets. The drying rate was increased with increasing of power density and vacuum degree, and improved the microwave gap ratio appropriately was conductive to speed up the drying process. In addition, the whole drying process was divided into two stages with different conditions, including the accelerated drying and falling rate drying. The time of accelerated drying was short and the main process was falling rate drying. The drying kinetics met Midilli model and it was suitable for describing osmosis dehydration vacuum-microwave drying process of tilapia fillet ( R2= 0.9873) . The results provide a new theory and technical guidance for tilapia processing and production.
In order to obtain the characteristics of tilapia fillets under osmosis dehydration vacuum-microwave drying conditions, the moisture content and drying rate of fish fillet were carried out during drying process.The effect of different microwave gap ratio, power density and vacuum degree on drying characteristic of fish fillet were determined and the drying kinetics model of osmosis dehydration vacuum-microwave drying was set up.The results showed that the microwave gap ratio, power density and vacuum degree had greater influences on dry characteristics of tilapia fillets. The drying rate was increased with increasing of power density and vacuum degree, and improved the microwave gap ratio appropriately was conductive to speed up the drying process. In addition, the whole drying process was divided into two stages with different conditions, including the accelerated drying and falling rate drying. The time of accelerated drying was short and the main process was falling rate drying. The drying kinetics met Midilli model and it was suitable for describing osmosis dehydration vacuum-microwave drying process of tilapia fillet ( R2= 0.9873) . The results provide a new theory and technical guidance for tilapia processing and production.
2017, (18): 36-39.
DOI: 10.13386/j.issn1002-0306.2017.18.007
Abstract：
The effects of 100, 200, 300, 400, 500 MPa ultra high pressure treatment on the melting point, solid fat content, crystal form, acid value, hardness, consistency and spread ability of butter were studied.The results showed that the ultra high pressure treatment could increase the melting point of butter and change crystal form to the blends of the β' and beta form.Ultra high pressure treatment had no significant effect on the FFA ( p > 0.05) , but decreased the solid fat content, hardness and consistency of the butter, and significant increased in spreadability ( p < 0.01) under low temperature ( 15 ℃) and room temperature ( 25 ℃) .
The effects of 100, 200, 300, 400, 500 MPa ultra high pressure treatment on the melting point, solid fat content, crystal form, acid value, hardness, consistency and spread ability of butter were studied.The results showed that the ultra high pressure treatment could increase the melting point of butter and change crystal form to the blends of the β' and beta form.Ultra high pressure treatment had no significant effect on the FFA ( p > 0.05) , but decreased the solid fat content, hardness and consistency of the butter, and significant increased in spreadability ( p < 0.01) under low temperature ( 15 ℃) and room temperature ( 25 ℃) .
Abstract：
Flammulina velutipes was used as raw materials. Polysaccharides from Flammulina velutipes ( FVP) were extracted using conventional water extraction.FVP-H, FVP-V and FVP-F were obtained with hot-air drying, vacuum drying and freeze drying, respectively.Component and antioxidant activities of FVP-H, FVP-V and FVP-F were investigated.The results showed that FVP were acidic polysaccharides.Different drying methods had no effect on the monosaccharide species. However, it could change the monosaccharide composition and uronic acid content.The relative molecular weight of FVP-H, FVP-V and FVP-F were not obvious, which were 2342309, 2375843 and 2358437 Da, respectively. FVP-H, FVP-V and FVP-F had a stronger scavenging ability of DPPH radical, hydroxyl radical, superoxide anion free radical and reducing power. In a certain concentration range, FVP were positively correlated with the antioxidant activity and reducing capacity.Different drying methods had different effects on the antioxidant activity of FVP. FVP-F had highest antioxidant activities, followed by FVP-V and FVP-H. Freeze-drying was the best drying method for preparation of FVP.
Flammulina velutipes was used as raw materials. Polysaccharides from Flammulina velutipes ( FVP) were extracted using conventional water extraction.FVP-H, FVP-V and FVP-F were obtained with hot-air drying, vacuum drying and freeze drying, respectively.Component and antioxidant activities of FVP-H, FVP-V and FVP-F were investigated.The results showed that FVP were acidic polysaccharides.Different drying methods had no effect on the monosaccharide species. However, it could change the monosaccharide composition and uronic acid content.The relative molecular weight of FVP-H, FVP-V and FVP-F were not obvious, which were 2342309, 2375843 and 2358437 Da, respectively. FVP-H, FVP-V and FVP-F had a stronger scavenging ability of DPPH radical, hydroxyl radical, superoxide anion free radical and reducing power. In a certain concentration range, FVP were positively correlated with the antioxidant activity and reducing capacity.Different drying methods had different effects on the antioxidant activity of FVP. FVP-F had highest antioxidant activities, followed by FVP-V and FVP-H. Freeze-drying was the best drying method for preparation of FVP.
Abstract：
Collagens were extracted from the fin, scale, skin, muscle, bone and swim bladder of white fish at different p H.HPLC, SDS-PAGE, peptide mapping and DSC were used to investigate the compositions and physiochemical properties of the collagens, which were extracted from different parts of white fish.The results showed that, collagens could be more soluble in the acidic p H range from 3 ~ 4, while the solubility decreased under neutral and alkaline condition. Extraction ratios of collagens from skin and swim bladder were 18.80% and 15.95% respectively, which were higher than those of other white fish parts.Similar peptide maps of collagens extracted from different parts of white fish indicated that primary structures of these collagens were quite similar in terms of amino acid sequence.Nearly 1/3 of the total amino acid was Gly, and a high level of Pro and Hyp up to 154.2199.0 residues/1000 residues.The collagens from all parts of white fish were comprised of two kinds α chains ( α1and α2) and classified as type I collagens.The denaturation temperatures of these collagens were between 34.1636.40 ℃.The collagens extracted from different parts of white fish had good similarity in composition, structure and physicochemical properties.
Collagens were extracted from the fin, scale, skin, muscle, bone and swim bladder of white fish at different p H.HPLC, SDS-PAGE, peptide mapping and DSC were used to investigate the compositions and physiochemical properties of the collagens, which were extracted from different parts of white fish.The results showed that, collagens could be more soluble in the acidic p H range from 3 ~ 4, while the solubility decreased under neutral and alkaline condition. Extraction ratios of collagens from skin and swim bladder were 18.80% and 15.95% respectively, which were higher than those of other white fish parts.Similar peptide maps of collagens extracted from different parts of white fish indicated that primary structures of these collagens were quite similar in terms of amino acid sequence.Nearly 1/3 of the total amino acid was Gly, and a high level of Pro and Hyp up to 154.2199.0 residues/1000 residues.The collagens from all parts of white fish were comprised of two kinds α chains ( α1and α2) and classified as type I collagens.The denaturation temperatures of these collagens were between 34.1636.40 ℃.The collagens extracted from different parts of white fish had good similarity in composition, structure and physicochemical properties.
Abstract：
To provide basis and reference for the utilization of walnut dietary fibers, walnut dietary fibers were extracted using chemical extraction methods and the physiochemical properties of five fibers with different particles sizes, including below 40 mesh, 4060 mesh, 6080 mesh, 80120 mesh, 120160 mesh and beyond 160 mesh, were also investigated.Results suggested that the yield of walnut dietary fibers, composing mainly of 76.34% of dietary fibers and 5.41% of protein, was 12.47%.Infrared spectroscopy scanning pictures indicated that walnut dietary fibers had remark absorbance at 3420 cm-1, suggesting fiber structure had not been destructed.The significant differences of water-keeping capability, swelling capability and viscosity were observed during determining physiochemical properties of five dietary fibers with varying particle sizes.The best water-keeping capability, 7.76 g·g-1, was observed in walnut dietary fibers with 120 ~ 160 mesh, and the best swelling capability and viscosity, 5.28 m L·g-1, 21.25 m Pa·s, respectively, both were observed in dietary fibers with 80120 mesh.However, walnut dietary fibers size over 160 mesh had the best oil-keeping capability, with 1.92 g·g-1. In addition, absorption capability of glucose was optimum at the particles 120 to 160 mesh, cation absorptin capability peaked at the particle range of 80 to 120 mesh.Overall, walnut dietary fibers with the particle size of 80160 mesh had the optimum physiochemical properties.
To provide basis and reference for the utilization of walnut dietary fibers, walnut dietary fibers were extracted using chemical extraction methods and the physiochemical properties of five fibers with different particles sizes, including below 40 mesh, 4060 mesh, 6080 mesh, 80120 mesh, 120160 mesh and beyond 160 mesh, were also investigated.Results suggested that the yield of walnut dietary fibers, composing mainly of 76.34% of dietary fibers and 5.41% of protein, was 12.47%.Infrared spectroscopy scanning pictures indicated that walnut dietary fibers had remark absorbance at 3420 cm-1, suggesting fiber structure had not been destructed.The significant differences of water-keeping capability, swelling capability and viscosity were observed during determining physiochemical properties of five dietary fibers with varying particle sizes.The best water-keeping capability, 7.76 g·g-1, was observed in walnut dietary fibers with 120 ~ 160 mesh, and the best swelling capability and viscosity, 5.28 m L·g-1, 21.25 m Pa·s, respectively, both were observed in dietary fibers with 80120 mesh.However, walnut dietary fibers size over 160 mesh had the best oil-keeping capability, with 1.92 g·g-1. In addition, absorption capability of glucose was optimum at the particles 120 to 160 mesh, cation absorptin capability peaked at the particle range of 80 to 120 mesh.Overall, walnut dietary fibers with the particle size of 80160 mesh had the optimum physiochemical properties.
2017, (18): 56-59.
DOI: 10.13386/j.issn1002-0306.2017.18.011
Abstract：
The rheological and processing characteristics such as water holding capacity and freeze-thaw stability of konjac gum were studied.The results showed that konjac gum solutions was pseudoplastic fluid and was thermally irreversible gel.Its water holding capacity was better but freeze-thaw stability was not good. Therefore, the using of konjac gum should be based on the specific situation in food processing.
The rheological and processing characteristics such as water holding capacity and freeze-thaw stability of konjac gum were studied.The results showed that konjac gum solutions was pseudoplastic fluid and was thermally irreversible gel.Its water holding capacity was better but freeze-thaw stability was not good. Therefore, the using of konjac gum should be based on the specific situation in food processing.
Abstract：
The effect of soybean, flaxseed and perilla seed oil on quality of grass carp surimi were investigated in this study.The changes of color, gel properties, water holding capacity ( WHC) , cooking loss, texture parameters and microstructure of the surimi gel in the presence of different concentrations of vegetable oil were analyzed. The results indicated that the addition of vegetable oil significantly increased the whiteness and cooking loss of surimi gel, but reduced WHC, gel strength, hardness, cohesiveness and chewiness. There was no significant difference in springiness, cohesiveness and resilience among all the samples.No significant influence was found when 3% vegetable oil was added into surimi gel.Especially for 3% perilla seed oil, the gel network structure of grass carp surimi was relatively smooth and there were no large holes.Meanwhile, the minimum decrease range of WHC and gel strength was found with an addition of 3% perilla seed oil.
The effect of soybean, flaxseed and perilla seed oil on quality of grass carp surimi were investigated in this study.The changes of color, gel properties, water holding capacity ( WHC) , cooking loss, texture parameters and microstructure of the surimi gel in the presence of different concentrations of vegetable oil were analyzed. The results indicated that the addition of vegetable oil significantly increased the whiteness and cooking loss of surimi gel, but reduced WHC, gel strength, hardness, cohesiveness and chewiness. There was no significant difference in springiness, cohesiveness and resilience among all the samples.No significant influence was found when 3% vegetable oil was added into surimi gel.Especially for 3% perilla seed oil, the gel network structure of grass carp surimi was relatively smooth and there were no large holes.Meanwhile, the minimum decrease range of WHC and gel strength was found with an addition of 3% perilla seed oil.
2017, (18): 65-68.
DOI: 10.13386/j.issn1002-0306.2017.18.013
Abstract：
Under the imitated physiological condition, the interaction between galangin and human serum albumin ( HSA) was studied by fluorescence quenching, synchronous fluorescence, three-dimensional fluorescence and circular dichroism spectra.The results suggested that galangin had a strong ability to quench the HSA fluorescence in a static mode, during which hydrogen bond and Van Edward force played dominant roles. The binding constants ( Ka) and site numbers ( n) obtained at different temperatures were 1.26 × 106L/mol, 1.17 ( 290.15 K) , 4.34 × 105L/mol, 1.09 ( 296.15 K) , 1.23 × 105L/mol, 1.00 ( 303.15 K) , 9.87 × 104L/mol, 0.99 ( 310.15 K) , respectively. Spectra of synchronous fluorescence, three-dimensional fluorescence and circular dichroism revealed that galangin interacted with tryptophan residues in BSA more strongly than with tyrosine residues, and the vicinity of tryptophan residues was less hydrophobic.However, conformational changes of HAS were slighter.
Under the imitated physiological condition, the interaction between galangin and human serum albumin ( HSA) was studied by fluorescence quenching, synchronous fluorescence, three-dimensional fluorescence and circular dichroism spectra.The results suggested that galangin had a strong ability to quench the HSA fluorescence in a static mode, during which hydrogen bond and Van Edward force played dominant roles. The binding constants ( Ka) and site numbers ( n) obtained at different temperatures were 1.26 × 106L/mol, 1.17 ( 290.15 K) , 4.34 × 105L/mol, 1.09 ( 296.15 K) , 1.23 × 105L/mol, 1.00 ( 303.15 K) , 9.87 × 104L/mol, 0.99 ( 310.15 K) , respectively. Spectra of synchronous fluorescence, three-dimensional fluorescence and circular dichroism revealed that galangin interacted with tryptophan residues in BSA more strongly than with tyrosine residues, and the vicinity of tryptophan residues was less hydrophobic.However, conformational changes of HAS were slighter.
2017, (18): 69-73.
DOI: 10.13386/j.issn1002-0306.2017.18.014
Abstract：
Rice glutelin was prone to thermal aggregation, and ionic strength had obvious effect on its thermal aggregation.Here, the effect laws and mechanisms of rice glutelin thermal aggregation by Na Cl were revealed.When Na Cl concentration increased from 00.15 mol·L-1, solubility of rice glutelin treated by heat decreased from 13.78% to 12.49%, which seemed not to be obvious, but the solubility was 10.62% when Na Cl concentration was 0.30 mol·L-1, and it appeared to be turbid.The turbidity of rice glutelin by heat treatment increased significantly from 0.052 to 0.191 when Na Cl concentration increased from00.30 mol·L-1, average particle size increased from 168 nm to 273 nm, and an aggregation peak rised, Zeta potential changed from -14.4 to-5.61, and hydrophobicity increased from 329.16 to 535.80, there was a slight blue shift for fluorescence emission spectrum of rice glutelin by heat treatment, and fluorescence intensity increased. Na Cl affected surface charge and hydrophobicity of rice glutelin by heat treatment, and promoted its thermal aggregation when concentration of Na Cl was more than 0.15 mol·L-1.
Rice glutelin was prone to thermal aggregation, and ionic strength had obvious effect on its thermal aggregation.Here, the effect laws and mechanisms of rice glutelin thermal aggregation by Na Cl were revealed.When Na Cl concentration increased from 00.15 mol·L-1, solubility of rice glutelin treated by heat decreased from 13.78% to 12.49%, which seemed not to be obvious, but the solubility was 10.62% when Na Cl concentration was 0.30 mol·L-1, and it appeared to be turbid.The turbidity of rice glutelin by heat treatment increased significantly from 0.052 to 0.191 when Na Cl concentration increased from00.30 mol·L-1, average particle size increased from 168 nm to 273 nm, and an aggregation peak rised, Zeta potential changed from -14.4 to-5.61, and hydrophobicity increased from 329.16 to 535.80, there was a slight blue shift for fluorescence emission spectrum of rice glutelin by heat treatment, and fluorescence intensity increased. Na Cl affected surface charge and hydrophobicity of rice glutelin by heat treatment, and promoted its thermal aggregation when concentration of Na Cl was more than 0.15 mol·L-1.
2017, (18): 74-78.
DOI: 10.13386/j.issn1002-0306.2017.18.015
Abstract：
In this study, lily was dried as thin-layers in the ranges of 65 85 ℃ of drying temperature in a hot-air dryer.The effect of drying hot-air temperature on the drying kinetics was analyzed.Five different dynamic models were fitted nonlinearly by using the drying test data of lily and the best suitable model was selected by comparing the values of the correlation coefficient ( R2) , the reduced chi-square ( χ2) and the root mean square error ( RMSE) .The results showed that drying process of lily scales and sliced lily occurred in the falling rate period, and the moisture transfer was controlled by internal diffusion.The Page model was the best suitable to descript the relationship of lily moisture and drying time by hot-air drying.The effective moisture diffusion coefficient (Deff) and the activation energy ( Ea) were also obtained by experiments under different conditions, the values of Deffwould increase with the addition of drying temperature, Deffvalues changed from 7.73 to 14.12 × 10-9m2/s for shred lily, while Deffvalues changed from 4.12 to 9.49 × 10-9m2/s for lily scales within the given temperature range. An Arrhenius relation with Eavalues of 42.42 and 30.37 k J/mol for lily scales and shredded lily expressed the effect of shred on the diffusivity.Shredded lily could short drying time and reduce energy consumption.
In this study, lily was dried as thin-layers in the ranges of 65 85 ℃ of drying temperature in a hot-air dryer.The effect of drying hot-air temperature on the drying kinetics was analyzed.Five different dynamic models were fitted nonlinearly by using the drying test data of lily and the best suitable model was selected by comparing the values of the correlation coefficient ( R2) , the reduced chi-square ( χ2) and the root mean square error ( RMSE) .The results showed that drying process of lily scales and sliced lily occurred in the falling rate period, and the moisture transfer was controlled by internal diffusion.The Page model was the best suitable to descript the relationship of lily moisture and drying time by hot-air drying.The effective moisture diffusion coefficient (Deff) and the activation energy ( Ea) were also obtained by experiments under different conditions, the values of Deffwould increase with the addition of drying temperature, Deffvalues changed from 7.73 to 14.12 × 10-9m2/s for shred lily, while Deffvalues changed from 4.12 to 9.49 × 10-9m2/s for lily scales within the given temperature range. An Arrhenius relation with Eavalues of 42.42 and 30.37 k J/mol for lily scales and shredded lily expressed the effect of shred on the diffusivity.Shredded lily could short drying time and reduce energy consumption.
Abstract：
The cereal-based medium for liquid fermentation was optimized according to the carotenoids production of three strains of Cordyceps militaris CM-03, CM-04 and CM-11.The media components of this work contained several kinds of grains such as wheat ( W) , corn ( C) , bean ( B) , rice ( R) , bran ( Br) and inorganic salts like MgSO4·7H2O ( Mg) , KH2PO4 ( KHP) and vitamin B1 ( VB1) .The results showed that the best culture medium formula for the carotenoids accumulation by Cordyceps militaris CM-03 consisted of W ( 1.4 g·L-1) , C ( 2.8 g·L-1) , B ( 0.3 g·L-1) , Mg ( 0.1 g·L-1) , KHP ( 0.1 g·L-1) and VB1 ( 0.05 mg·L-1) , with natural pH, with the carotenoids yield of ( 694.8 ± 15.4) μg/g.For Cordyceps militaris CM-04, its highest carotenoids output was ( 708.5 ± 25.8) μg/g under the formula consisted of R ( 1.2 g·L-1) , C ( 0.6 g·L-1) , B ( 0.3 g·L-1) , Mg ( 0.1 g·L-1) , KHP ( 0.1 g·L-1) , VB1 ( 0.05 mg·L-1) with natural p H.The highest carotenoids output of Cordyceps militaris CM-11 was ( 700.5 ± 19.1) μg/g with natural p H, the formula formed by W ( 1.7 g·L-1) , C ( 2.6 g·L-1) , B ( 0.3 g·L-1) , Mg ( 0.1 g·L-1) , KHP ( 0.1 g·L-1) and VB1 ( 0.05 mg·L-1) .The extraction process with ethanol was also optimized in this work, and the results showed that the optimal extraction condition was as follows: grinding with quartz sand, ethanol concentration 60%, material to liquid ratio 1∶ 40, water bath temperature 80 ℃, extraction level 2, and extraction rate of92.8%.
The cereal-based medium for liquid fermentation was optimized according to the carotenoids production of three strains of Cordyceps militaris CM-03, CM-04 and CM-11.The media components of this work contained several kinds of grains such as wheat ( W) , corn ( C) , bean ( B) , rice ( R) , bran ( Br) and inorganic salts like MgSO4·7H2O ( Mg) , KH2PO4 ( KHP) and vitamin B1 ( VB1) .The results showed that the best culture medium formula for the carotenoids accumulation by Cordyceps militaris CM-03 consisted of W ( 1.4 g·L-1) , C ( 2.8 g·L-1) , B ( 0.3 g·L-1) , Mg ( 0.1 g·L-1) , KHP ( 0.1 g·L-1) and VB1 ( 0.05 mg·L-1) , with natural pH, with the carotenoids yield of ( 694.8 ± 15.4) μg/g.For Cordyceps militaris CM-04, its highest carotenoids output was ( 708.5 ± 25.8) μg/g under the formula consisted of R ( 1.2 g·L-1) , C ( 0.6 g·L-1) , B ( 0.3 g·L-1) , Mg ( 0.1 g·L-1) , KHP ( 0.1 g·L-1) , VB1 ( 0.05 mg·L-1) with natural p H.The highest carotenoids output of Cordyceps militaris CM-11 was ( 700.5 ± 19.1) μg/g with natural p H, the formula formed by W ( 1.7 g·L-1) , C ( 2.6 g·L-1) , B ( 0.3 g·L-1) , Mg ( 0.1 g·L-1) , KHP ( 0.1 g·L-1) and VB1 ( 0.05 mg·L-1) .The extraction process with ethanol was also optimized in this work, and the results showed that the optimal extraction condition was as follows: grinding with quartz sand, ethanol concentration 60%, material to liquid ratio 1∶ 40, water bath temperature 80 ℃, extraction level 2, and extraction rate of92.8%.
Abstract：
With the raw material of euphausia superba powder, the purity of the refining phosphatidylcholine gained by ethyl alcohol extraction and separation and purification reached 90.8%, then the refining phosphatidylcholine was used as raw material and phospholipase A2 was used to catalyze the fatty acid hydrolysis of Sn-2 position of phosphatidylcholine in supercritical CO2 system to make the fish oil DHA to Sn-2 position and form the DHA-PC with high DHA contents.Meanwhile, the effects of different parameters on the reaction were surveyed.The results showed that, the best additive amount of immobilization phospholipase A2 was 15% ( occupied the total substratio) , the best enzymolysis was 6 h, the best enzymolysis temperature was 55 ℃, the best enzymolysis pressure was 12 MPa, respectively.Under such condition, the DHA binding ratio of euphausia superba phosphatidylcholine could reach 62.3 mol%. And it could be concluded that immobilization phospholipase A2 is highly viable for phosphatidylcholine modification to prepare DHA-PC.
With the raw material of euphausia superba powder, the purity of the refining phosphatidylcholine gained by ethyl alcohol extraction and separation and purification reached 90.8%, then the refining phosphatidylcholine was used as raw material and phospholipase A2 was used to catalyze the fatty acid hydrolysis of Sn-2 position of phosphatidylcholine in supercritical CO2 system to make the fish oil DHA to Sn-2 position and form the DHA-PC with high DHA contents.Meanwhile, the effects of different parameters on the reaction were surveyed.The results showed that, the best additive amount of immobilization phospholipase A2 was 15% ( occupied the total substratio) , the best enzymolysis was 6 h, the best enzymolysis temperature was 55 ℃, the best enzymolysis pressure was 12 MPa, respectively.Under such condition, the DHA binding ratio of euphausia superba phosphatidylcholine could reach 62.3 mol%. And it could be concluded that immobilization phospholipase A2 is highly viable for phosphatidylcholine modification to prepare DHA-PC.
Abstract：
The model of tertiary of β-conglycinin beta-subunit was constructed by the bioinformation tool SWISS-MODEL, and the conformational epitopes were predicted by Disco Tope 2.0 server.The overlapping fragments of β-conglycinin beta-subunit genes were amplified by PCR and inserted into p MD-18 T vector, then preserved into competent cell of Escherichia coli JM109.The recombinant plasmids were evaluated by blue-white selection, PCR and double enzyme digestion, and DNA sequence analysis showed that the cloned sequence was the very fragment designed. The successful cloning of the genes can provide a reference for the study of the expresstion of β-conglycinin beta-subunit and screening of antigenic epitopes.
The model of tertiary of β-conglycinin beta-subunit was constructed by the bioinformation tool SWISS-MODEL, and the conformational epitopes were predicted by Disco Tope 2.0 server.The overlapping fragments of β-conglycinin beta-subunit genes were amplified by PCR and inserted into p MD-18 T vector, then preserved into competent cell of Escherichia coli JM109.The recombinant plasmids were evaluated by blue-white selection, PCR and double enzyme digestion, and DNA sequence analysis showed that the cloned sequence was the very fragment designed. The successful cloning of the genes can provide a reference for the study of the expresstion of β-conglycinin beta-subunit and screening of antigenic epitopes.
Abstract：
A strain of lactic acid bacteria was screened out from the tofu acid pulp by the plate coating method and high performance liquid chromatography with the p H and lactic acid yield as indexes. The morphological observation, colony morphological observation, physiological and biochemical identification and 16S rDNA sequence analysis of the strain were carried out, and the results showed that the lactic acid bacteria belonged to Lactobacillus casei. The isolated Lactobacillus casei YQ336 was inoculated into bean curd water and fermented into tofu coagulant to make tofu, compared with tofu made from natural fermented acid pulp, it was found that there was no significant difference between the two sensory scores ( p > 0.05) .The result indicated that Lactobacillus casei YQ336 can be developed and used as a new tofu coagulant.
A strain of lactic acid bacteria was screened out from the tofu acid pulp by the plate coating method and high performance liquid chromatography with the p H and lactic acid yield as indexes. The morphological observation, colony morphological observation, physiological and biochemical identification and 16S rDNA sequence analysis of the strain were carried out, and the results showed that the lactic acid bacteria belonged to Lactobacillus casei. The isolated Lactobacillus casei YQ336 was inoculated into bean curd water and fermented into tofu coagulant to make tofu, compared with tofu made from natural fermented acid pulp, it was found that there was no significant difference between the two sensory scores ( p > 0.05) .The result indicated that Lactobacillus casei YQ336 can be developed and used as a new tofu coagulant.
Abstract：
The 150 days old castrated hen breasts in Yunnan Wuding were used as material, the degree of hydrolysis ( DH) was analyzed, based on the results of the single-factor tests, the optimal hydrolysis condition for chicken breast hydrolyzed by papain and neutral protease was obtained through the Box-Behnken methodology.The results showed that the model was highly significant ( p < 0.0001) , and the lack of fit was not significant ( p = 0.1441 > 0.05) , R2= 0.9919, Radj2= 0.9815. The optimal enzymolysising process was as follows: papain and neutral protease were mixed and added at the same time, papain and neutral protease was 0.27% and 0.13% respectively, temperature 54.3 ℃, p H6.8, after 5 h under the above reaction conditions, the DH reached 36.03% ± 0.31%, agreed with the predicted value 36.26%. Therefore, the model has a good fit result and provides reference for practical application.
The 150 days old castrated hen breasts in Yunnan Wuding were used as material, the degree of hydrolysis ( DH) was analyzed, based on the results of the single-factor tests, the optimal hydrolysis condition for chicken breast hydrolyzed by papain and neutral protease was obtained through the Box-Behnken methodology.The results showed that the model was highly significant ( p < 0.0001) , and the lack of fit was not significant ( p = 0.1441 > 0.05) , R2= 0.9919, Radj2= 0.9815. The optimal enzymolysising process was as follows: papain and neutral protease were mixed and added at the same time, papain and neutral protease was 0.27% and 0.13% respectively, temperature 54.3 ℃, p H6.8, after 5 h under the above reaction conditions, the DH reached 36.03% ± 0.31%, agreed with the predicted value 36.26%. Therefore, the model has a good fit result and provides reference for practical application.
Abstract：
Screening on lactic acid bacteria with antibacterial activity, isolated from fermented pickle in eastern Inner Mongolia, was tested for Escherichia coli and Staphylococcus aureus as the indicator, and its antibacterial spectrum was tested.The optimum separation conditions of antibacterial substances were determined by single factor and L9 ( 34) orthogonal test, and detected antibacterial effect in commercial cattle feed.The result showed that the strain S1-4 had strong and stable antibacterial activity in 14 strains of lactic acid bacteria, and the diameter of inhibition zone of strain S1-4 to Escherichia coli and Staphylococcus aureus was ( 19.69 ± 0.71) mm and ( 20.59 ± 0.26) mm, respectively, and showed broad antimicrobial spectrum. The optimal extraction conditions for the antibacterial substances from strain S1-4 were as follows: the precipitation of p H was 5, the concentration of ethanol was 95%, the settling time was 8 h, and the ratio of material to liquid was 1 ∶ 4 ( v ∶ v) . In these conditions, the diameter of the inhibition zone was 39.53 mm, and increased by 23.18%.The fermentation broth of strain S1-4was added to the cattle feed, which could inhibit the growth of bacteria and mould in feed, and with the increase of the dosage, the inhibitory effect increased obviously.
Screening on lactic acid bacteria with antibacterial activity, isolated from fermented pickle in eastern Inner Mongolia, was tested for Escherichia coli and Staphylococcus aureus as the indicator, and its antibacterial spectrum was tested.The optimum separation conditions of antibacterial substances were determined by single factor and L9 ( 34) orthogonal test, and detected antibacterial effect in commercial cattle feed.The result showed that the strain S1-4 had strong and stable antibacterial activity in 14 strains of lactic acid bacteria, and the diameter of inhibition zone of strain S1-4 to Escherichia coli and Staphylococcus aureus was ( 19.69 ± 0.71) mm and ( 20.59 ± 0.26) mm, respectively, and showed broad antimicrobial spectrum. The optimal extraction conditions for the antibacterial substances from strain S1-4 were as follows: the precipitation of p H was 5, the concentration of ethanol was 95%, the settling time was 8 h, and the ratio of material to liquid was 1 ∶ 4 ( v ∶ v) . In these conditions, the diameter of the inhibition zone was 39.53 mm, and increased by 23.18%.The fermentation broth of strain S1-4was added to the cattle feed, which could inhibit the growth of bacteria and mould in feed, and with the increase of the dosage, the inhibitory effect increased obviously.
Abstract：
In this study, Laminaria japonica from Qingdao sea area was used to isolate and purify endophytic fungus.A total of seven strains of endophytic fungi were isolated. Using modified Ellman method to determine the inhibitory rate of ACh E and active strains were identified.Strain ML-X showed the highest AChE inhibitory activity and was identified, by physiologicalbiochemical characteristics and molecular biological techniques of 18 S rDNA sequencing.Based on single factor and orthogonal test, the culture conditions of liquid fermentation of the endophytic fungi were screened out. The results showed that the strain ML-X was confirmed as Geotrichum candidum, and the optimal fermentation conditions were as follows: PS medium was the suitable medium for the strain at pH6.0, incubated with 5% inoculum and 150 m L/500 m L culture volume at 31 ℃ for 8 days.Under these conditions, the strain ML-X exhibited a higher ACh E inhibitory activity, the inhibition ratio of Ach E was 28.91%± 0.25% when the concentration of crude extract from fermentation broth was 5 mg/m L.
In this study, Laminaria japonica from Qingdao sea area was used to isolate and purify endophytic fungus.A total of seven strains of endophytic fungi were isolated. Using modified Ellman method to determine the inhibitory rate of ACh E and active strains were identified.Strain ML-X showed the highest AChE inhibitory activity and was identified, by physiologicalbiochemical characteristics and molecular biological techniques of 18 S rDNA sequencing.Based on single factor and orthogonal test, the culture conditions of liquid fermentation of the endophytic fungi were screened out. The results showed that the strain ML-X was confirmed as Geotrichum candidum, and the optimal fermentation conditions were as follows: PS medium was the suitable medium for the strain at pH6.0, incubated with 5% inoculum and 150 m L/500 m L culture volume at 31 ℃ for 8 days.Under these conditions, the strain ML-X exhibited a higher ACh E inhibitory activity, the inhibition ratio of Ach E was 28.91%± 0.25% when the concentration of crude extract from fermentation broth was 5 mg/m L.
2017, (18): 117-122.
DOI: 10.13386/j.issn1002-0306.2017.18.023
Abstract：
Passionflower peel was used as raw materials in the reseach.With enzyme solution p H, hydrolysis time, hydrolysis temperature, enzyme concentration and ratio of liquid to material as single factors, the effects of four kinds of enzyme ( cellulase, hemicellulase and lignin enzymes, amylase) on pectin extraction from the passionflower peel were studied. And the enzyme combination consists cellulose, hemicellulase and lignin enzymes were determined. Through L9 ( 34) orthogonal experiment and response surface test, the enzymatic hydrolysis and enzyme concentration were optimized. the optimal enzymatic hydrolysis conditions were as follows: cellulose enzymes 0.8 g/100 g, hemicellulase 1.2 g/100 g, and lignin 0.2 g/100 g, ratio of liquid to material ( m L/g) 6∶ 1, p H value 4, extraction lasts for 3.5 h under the temperature of 40 ℃, the pectin gain rate can reach2.63% ± 0.021%.
Passionflower peel was used as raw materials in the reseach.With enzyme solution p H, hydrolysis time, hydrolysis temperature, enzyme concentration and ratio of liquid to material as single factors, the effects of four kinds of enzyme ( cellulase, hemicellulase and lignin enzymes, amylase) on pectin extraction from the passionflower peel were studied. And the enzyme combination consists cellulose, hemicellulase and lignin enzymes were determined. Through L9 ( 34) orthogonal experiment and response surface test, the enzymatic hydrolysis and enzyme concentration were optimized. the optimal enzymatic hydrolysis conditions were as follows: cellulose enzymes 0.8 g/100 g, hemicellulase 1.2 g/100 g, and lignin 0.2 g/100 g, ratio of liquid to material ( m L/g) 6∶ 1, p H value 4, extraction lasts for 3.5 h under the temperature of 40 ℃, the pectin gain rate can reach2.63% ± 0.021%.
Abstract：
Objective: Lactococcus raffinolactis Y-12 was isolated from Dushan pickled Chinese cabbage, and the fermentation conditions of bacteriocin produced from it were optimized.Methods: The factors including fermentation time, temperature, initial p H, glucose and so on, that affected the yield of bacteriocin, were studied in single factor and Plackett-Burman optimization test.On the basis of single factor test and Plackett-Burman treatment, the conditions for bacteriocin production were explored by Box-Behnken design involving the peptone, glucose and initial p H at three levels in combination with response surface methodology. Results: The optimal combination of the medium constituents for bacteriocin production were as follows:fermentation temperature 35 ℃, fermentation time 36 h, inoculums concentration 2%, 10.62 g/L peptone, 31.61 g/L glucose, initial p H6.46, the other composition of MRS medium were unchange.Under the optimal condition, the inhibitory zone diameter was 16.87 mm, than before optimization ( 14.12 mm) to improve 19.5%.Conclusion: The experimental results were in agreement with the prediction values, indicated the established regression model was feasible.
Objective: Lactococcus raffinolactis Y-12 was isolated from Dushan pickled Chinese cabbage, and the fermentation conditions of bacteriocin produced from it were optimized.Methods: The factors including fermentation time, temperature, initial p H, glucose and so on, that affected the yield of bacteriocin, were studied in single factor and Plackett-Burman optimization test.On the basis of single factor test and Plackett-Burman treatment, the conditions for bacteriocin production were explored by Box-Behnken design involving the peptone, glucose and initial p H at three levels in combination with response surface methodology. Results: The optimal combination of the medium constituents for bacteriocin production were as follows:fermentation temperature 35 ℃, fermentation time 36 h, inoculums concentration 2%, 10.62 g/L peptone, 31.61 g/L glucose, initial p H6.46, the other composition of MRS medium were unchange.Under the optimal condition, the inhibitory zone diameter was 16.87 mm, than before optimization ( 14.12 mm) to improve 19.5%.Conclusion: The experimental results were in agreement with the prediction values, indicated the established regression model was feasible.
Abstract：
Objective: Screen chitin-deacetylase-producing strains from marine samples, identify the strain and optimize its fermentation conditions.Methods: Chitin-deacetylase-producing strains were screened by color culture medium from the marine mud of Yanwei Harbor. The strains were identified by morphological, physiological and biochemical characteristics and16 S r DNA sequence analysis. The single factor and orthogonal experimental design were used to optimize the fermentation conditions.Results: Strain MCDA01 producing chitin deacetylase was screened, and it was identified as Acinetobacter schindleri through morphological, biochemical characteristics, and 16 S r DNA sequence analysis. The optimal culture conditions of strain MCDA01 was obtained as follows: 30 ℃, p H8.0, and Na Cl 4%.The optimal fermentation conditions was obtained as follows: the fermentation time was 60 h, the fermentation temperature was 20 ℃, the culture medium starts p H was 7, the liquid loading amount was 20%, and the inducer chitin concentration was 1%. Under this condition, production of enzyme was up to201.37 U/m L, which was increased by 4.14 times. Conclusion: The maximum of enzyme production were optimized to201.37 U/m L, and have industrial application potential.
Objective: Screen chitin-deacetylase-producing strains from marine samples, identify the strain and optimize its fermentation conditions.Methods: Chitin-deacetylase-producing strains were screened by color culture medium from the marine mud of Yanwei Harbor. The strains were identified by morphological, physiological and biochemical characteristics and16 S r DNA sequence analysis. The single factor and orthogonal experimental design were used to optimize the fermentation conditions.Results: Strain MCDA01 producing chitin deacetylase was screened, and it was identified as Acinetobacter schindleri through morphological, biochemical characteristics, and 16 S r DNA sequence analysis. The optimal culture conditions of strain MCDA01 was obtained as follows: 30 ℃, p H8.0, and Na Cl 4%.The optimal fermentation conditions was obtained as follows: the fermentation time was 60 h, the fermentation temperature was 20 ℃, the culture medium starts p H was 7, the liquid loading amount was 20%, and the inducer chitin concentration was 1%. Under this condition, production of enzyme was up to201.37 U/m L, which was increased by 4.14 times. Conclusion: The maximum of enzyme production were optimized to201.37 U/m L, and have industrial application potential.
Abstract：
The crude cathepsin D was obtained from sea cucumber ( Stichopus japonicus) guts in this paper.The crude cathepsin D was extracted by using 50 mmol/L Glycine-HCl buffer ( p H3.0) with material to solvent ratio of 1∶ 6 ( w/v) at 4 ℃ for 1 h.The activity and characterization of the enzyme were investigated by using acid denatured hemoglobin as a substrate.The results showed that the optimum p H of the crude cathepsin D was p H3.0 and was stable between p H3.0 ~ 7.0. The crude cathepsin D exhibited its optimal temperature at 50 ℃ and was stable at 4 ~ 40 ℃. The crude cathepsin D was activated by metal ions of Mg2+, Ca2+, Ni2+, Zn2+, Cd2+and K+, while inhibited by Fe3+ and Fe2+at concentration of 5 mmol/L.The crude cathepsin D was strongly inhibited by aspartic protease inhibitor pepstatin A. These results suggested that the crude cathepsin D obtained from S.japonicus guts was acid protease maily composed of aspartic protease under the condition of present study.
The crude cathepsin D was obtained from sea cucumber ( Stichopus japonicus) guts in this paper.The crude cathepsin D was extracted by using 50 mmol/L Glycine-HCl buffer ( p H3.0) with material to solvent ratio of 1∶ 6 ( w/v) at 4 ℃ for 1 h.The activity and characterization of the enzyme were investigated by using acid denatured hemoglobin as a substrate.The results showed that the optimum p H of the crude cathepsin D was p H3.0 and was stable between p H3.0 ~ 7.0. The crude cathepsin D exhibited its optimal temperature at 50 ℃ and was stable at 4 ~ 40 ℃. The crude cathepsin D was activated by metal ions of Mg2+, Ca2+, Ni2+, Zn2+, Cd2+and K+, while inhibited by Fe3+ and Fe2+at concentration of 5 mmol/L.The crude cathepsin D was strongly inhibited by aspartic protease inhibitor pepstatin A. These results suggested that the crude cathepsin D obtained from S.japonicus guts was acid protease maily composed of aspartic protease under the condition of present study.
2017, (18): 140-144.
DOI: 10.13386/j.issn1002-0306.2017.18.027
Abstract：
Egg fermented production ( egg sufu) was studied, which could expand the variety of egg products, enrich the market, and increase the added value of eggs.Through single factor experiments and orthogonal experiment method, the effects of four conditions, including post fermentation time, maltose, pH and KH2PO4, were researched, with total acid, amino nitrogen and sensory evaluation be evaluation of egg sufu quality. Ultimately, experimental conditions were maltose 0%, natural egg p H, KH2PO40.05%, 10 weeks after the fermentation production of egg pickled tofu. Under these conditions, the total acid was0.695 g/100 g, with amino acid nitrogen 0.425 g/100 g and the sensory evaluation 87. In this study, the post fermentation parameters of egg sufu was optimized, which increased varieties of deep processing of egg product and be helpful to future industrial production.
Egg fermented production ( egg sufu) was studied, which could expand the variety of egg products, enrich the market, and increase the added value of eggs.Through single factor experiments and orthogonal experiment method, the effects of four conditions, including post fermentation time, maltose, pH and KH2PO4, were researched, with total acid, amino nitrogen and sensory evaluation be evaluation of egg sufu quality. Ultimately, experimental conditions were maltose 0%, natural egg p H, KH2PO40.05%, 10 weeks after the fermentation production of egg pickled tofu. Under these conditions, the total acid was0.695 g/100 g, with amino acid nitrogen 0.425 g/100 g and the sensory evaluation 87. In this study, the post fermentation parameters of egg sufu was optimized, which increased varieties of deep processing of egg product and be helpful to future industrial production.
Abstract：
Alternaria is one of the main pathogenic bacteria of fruit black spot and severely impairs the postharvest storage process of fruit.Alternaria was isolated from the pear and apple of a orchard in south Xinjiang and identified by morphological characteristics and molecular biological methods.110 strains of lactic acid bacteria ( LAB) from Xinjiang dairy products were performed to detect the inhibitory activity on Alternaria and solid cake, stationary and shaker broth were used for fermentation.The results showed that 2 strains of Alternaria named Alternaria gaisen and Alternaria tenuissima were obtained.4 strains of LAB with inhibitory activity on Alternaria were screened out and 3 of them were Lactobacillus pentosus, the other one named Lactobacillus paracasei.At the same time, the highest inhibitory activity on Alternaria was from shaker fermentation broth and the diameter of the zone of inhibition was up to 21.17 mm.It provided a theoretical basis to apply LAB from dairy products to control the black spot disease caused by Alternaria in the postharvest.
Alternaria is one of the main pathogenic bacteria of fruit black spot and severely impairs the postharvest storage process of fruit.Alternaria was isolated from the pear and apple of a orchard in south Xinjiang and identified by morphological characteristics and molecular biological methods.110 strains of lactic acid bacteria ( LAB) from Xinjiang dairy products were performed to detect the inhibitory activity on Alternaria and solid cake, stationary and shaker broth were used for fermentation.The results showed that 2 strains of Alternaria named Alternaria gaisen and Alternaria tenuissima were obtained.4 strains of LAB with inhibitory activity on Alternaria were screened out and 3 of them were Lactobacillus pentosus, the other one named Lactobacillus paracasei.At the same time, the highest inhibitory activity on Alternaria was from shaker fermentation broth and the diameter of the zone of inhibition was up to 21.17 mm.It provided a theoretical basis to apply LAB from dairy products to control the black spot disease caused by Alternaria in the postharvest.
2017, (18): 151-154.
DOI: 10.13386/j.issn1002-0306.2017.18.029
Abstract：
To explore the change of bacterial communities of Daqu in different storage rooms, the V3 and V4 regions of bacterial16 S r DNA were analyzed by high-throughput sequencing, the relationship between different Daqu and bacterial diversity was revealed combining the methods of principal co-ordinates analysis and linear discriminant analysis.The groups of A and B were selected in this experiment, according to the tracking data of the department, the mean value of saccharifying power of group A was a half of group B, which indicated obvious difference.The results showed that bacterial community structure was constantly adjusted, Lactococcus and Sebaldella became the dominant genera of group A in the end of storage, while the dominant genera was Bacillus in group B.The bacterial diversity of Daqu had a great difference in group A, in which Thermoctinomyces were the significantly different microbes, while Bacillus were the specific bacterium in group B.
To explore the change of bacterial communities of Daqu in different storage rooms, the V3 and V4 regions of bacterial16 S r DNA were analyzed by high-throughput sequencing, the relationship between different Daqu and bacterial diversity was revealed combining the methods of principal co-ordinates analysis and linear discriminant analysis.The groups of A and B were selected in this experiment, according to the tracking data of the department, the mean value of saccharifying power of group A was a half of group B, which indicated obvious difference.The results showed that bacterial community structure was constantly adjusted, Lactococcus and Sebaldella became the dominant genera of group A in the end of storage, while the dominant genera was Bacillus in group B.The bacterial diversity of Daqu had a great difference in group A, in which Thermoctinomyces were the significantly different microbes, while Bacillus were the specific bacterium in group B.
2017, (18): 155-159.
DOI: 10.13386/j.issn1002-0306.2017.18.030
Abstract：
The extraction methods of phosphatidylinositol from soybean lecithin powder by ionic liquid and ultrasonic wave were studied.The effects of extraction times, solid-liquid ratio, ehanol-[Bmim]OH ratio, extraction temperature, extraction time and ultrasonic power on the purity and extraction ratio of phosphatidylinositol were investigated. The purified phosphatidylinositol products were obtained at the conditions as follows: extraction times 3, solid-liquid ratio 1 ∶ 12, ehanol-[Bmim]OH ratio100∶ 7, extraction temperature 35 ℃, extraction time 15 min and ultrasonic power 360 W.Under these conditions, the purity and extracting yield of phosphatidylinositol were 79.53% ± 3.26% and 68.26% ± 1.15%, respectively.
The extraction methods of phosphatidylinositol from soybean lecithin powder by ionic liquid and ultrasonic wave were studied.The effects of extraction times, solid-liquid ratio, ehanol-[Bmim]OH ratio, extraction temperature, extraction time and ultrasonic power on the purity and extraction ratio of phosphatidylinositol were investigated. The purified phosphatidylinositol products were obtained at the conditions as follows: extraction times 3, solid-liquid ratio 1 ∶ 12, ehanol-[Bmim]OH ratio100∶ 7, extraction temperature 35 ℃, extraction time 15 min and ultrasonic power 360 W.Under these conditions, the purity and extracting yield of phosphatidylinositol were 79.53% ± 3.26% and 68.26% ± 1.15%, respectively.
Abstract：
In order to improve the desalting efficiency and reduce the nutrient losses of salted Apostichopus japonicus, the desalting process was adopted in still water under atmospheric.The optimization of desalted temperature, solid to solvent ratio, desalting time and water changing times based on desalination rate of salted Apostichopus japonicus was performed using combination of one-factor-at-a-time method and response surface methodology.The results showed that desalination rate was affected in decreasing order by the three factors: solid to solvent ratio, desalting time and water changing times. A desalted temperature of 25 ℃, solid to solvent ratio of 1 ∶ 4.3 g/m L, desalting time of 240 min and water changing times of 2 proved optimal.Experiments carried out under the optimized conditions led to a desalination rate of 85.98% ± 0.22%, good agreement with the predicted value.
In order to improve the desalting efficiency and reduce the nutrient losses of salted Apostichopus japonicus, the desalting process was adopted in still water under atmospheric.The optimization of desalted temperature, solid to solvent ratio, desalting time and water changing times based on desalination rate of salted Apostichopus japonicus was performed using combination of one-factor-at-a-time method and response surface methodology.The results showed that desalination rate was affected in decreasing order by the three factors: solid to solvent ratio, desalting time and water changing times. A desalted temperature of 25 ℃, solid to solvent ratio of 1 ∶ 4.3 g/m L, desalting time of 240 min and water changing times of 2 proved optimal.Experiments carried out under the optimized conditions led to a desalination rate of 85.98% ± 0.22%, good agreement with the predicted value.
2017, (18): 165-172.
DOI: 10.13386/j.issn1002-0306.2017.18.032
Abstract：
The object of this work was to establish a method of linear dextrin fractionated by alcohol gradient dissolution on basis of the solubility of linear dextrin in alcohol solution.The effects of ratios of linear dextrin to alcohol solution, p H and salt ( KCl) on linear dextrin fractionation were investigated using the average molecular-weight dispersity ( DMa) as an evaluation index.The results showed that the DMa of fractions was lowest when the ratio of linear dextrin to alcohol solution was 1 ∶ 100. It confirmed that the fractionation under this condition was best.Besides, this method of fractionation was applicable in the acidic, neutral, and alkaline environments. The dextrin fractionation at p H6.00 was optimal. However, the existence of salt was not favorable for the fractionation of dextrin.These results suggested that gradient alcohol dissolution, which was simple and lowcost, was an efficient method for fractionating linear dextrin into fractions with different molar masses of low DM.
The object of this work was to establish a method of linear dextrin fractionated by alcohol gradient dissolution on basis of the solubility of linear dextrin in alcohol solution.The effects of ratios of linear dextrin to alcohol solution, p H and salt ( KCl) on linear dextrin fractionation were investigated using the average molecular-weight dispersity ( DMa) as an evaluation index.The results showed that the DMa of fractions was lowest when the ratio of linear dextrin to alcohol solution was 1 ∶ 100. It confirmed that the fractionation under this condition was best.Besides, this method of fractionation was applicable in the acidic, neutral, and alkaline environments. The dextrin fractionation at p H6.00 was optimal. However, the existence of salt was not favorable for the fractionation of dextrin.These results suggested that gradient alcohol dissolution, which was simple and lowcost, was an efficient method for fractionating linear dextrin into fractions with different molar masses of low DM.
Abstract：
The size of inhibition zone was the index, S. aureus and E. coli were the indicator bacteria, to determine the best extraction method by comparing the bacteriostatic effect of extracts from water extraction, ultrasonic extraction, reflux extraction.Basis on the single-factor experiment, orthogonal experiment was used to optimize the extraction process.The effect of extracts from the optimal process on S.aureus, E.coli, E.aerogenes, P.aeruginosa, S.sonnei, C.albicans was determined.The results showed that the best extraction process was the use of water as solvent, ultrasound extraction, ultrasonic power 250 W, at roomtemperature, material liquid ratio of 1∶ 25, extraction for 30 minutes, extracted 2 times. Under these condition of extraction, the diameter of bacteriostatic rings against S.aureus, E.coli were 24.67 mm and 15.67 mm, and the diameter of bacteriostatic rings against E.aerogenes, P.aeruginosa, S.sonnei were 13.67~ 17.33 mm, and the extraction had no inhibitory effect on C.albicans.
The size of inhibition zone was the index, S. aureus and E. coli were the indicator bacteria, to determine the best extraction method by comparing the bacteriostatic effect of extracts from water extraction, ultrasonic extraction, reflux extraction.Basis on the single-factor experiment, orthogonal experiment was used to optimize the extraction process.The effect of extracts from the optimal process on S.aureus, E.coli, E.aerogenes, P.aeruginosa, S.sonnei, C.albicans was determined.The results showed that the best extraction process was the use of water as solvent, ultrasound extraction, ultrasonic power 250 W, at roomtemperature, material liquid ratio of 1∶ 25, extraction for 30 minutes, extracted 2 times. Under these condition of extraction, the diameter of bacteriostatic rings against S.aureus, E.coli were 24.67 mm and 15.67 mm, and the diameter of bacteriostatic rings against E.aerogenes, P.aeruginosa, S.sonnei were 13.67~ 17.33 mm, and the extraction had no inhibitory effect on C.albicans.
Abstract：
In order to obtain the best condition of hot water extraction of lotus seed polysaccharides, the effects of three single factors ( extraction temperature, extraction time, ratio of water volume to raw material weight ( w/m ratio) ) on the yield of lotus seed polysaccharides were investigated.Based on the data of single factor experiments, the optimal extraction technology of lotus seed polysaccharides was obtained by response surface methodology was as follows.: extraction temperature was 83 ℃, extraction time was 3 h, the ratio of water volume to raw material weight ( w/m) was 30 ∶ 1 m L/g. Under these conditions, the yield of polysaccharides was 8.13% ± 0.04%, which was consistent with the theoretical prediction value ( difference value lower than 1%) .Moreover, the microstructure of lotus seed powder before extraction and after extraction were observed and compared by environmental scanning electron microscopy. The results showed that: the whole cells of lotus seed powder were destroyed after hot-water extraction. The powder was different sizes, and its surface displayed schistose shapes, rough and irregular cracks.The microstructure of lotus seed powder before and after extraction was significantly different.It indicated that the soluble polysaccharides could be extracted greatly from lotus seed powder using the optimized hot water extraction process.
In order to obtain the best condition of hot water extraction of lotus seed polysaccharides, the effects of three single factors ( extraction temperature, extraction time, ratio of water volume to raw material weight ( w/m ratio) ) on the yield of lotus seed polysaccharides were investigated.Based on the data of single factor experiments, the optimal extraction technology of lotus seed polysaccharides was obtained by response surface methodology was as follows.: extraction temperature was 83 ℃, extraction time was 3 h, the ratio of water volume to raw material weight ( w/m) was 30 ∶ 1 m L/g. Under these conditions, the yield of polysaccharides was 8.13% ± 0.04%, which was consistent with the theoretical prediction value ( difference value lower than 1%) .Moreover, the microstructure of lotus seed powder before extraction and after extraction were observed and compared by environmental scanning electron microscopy. The results showed that: the whole cells of lotus seed powder were destroyed after hot-water extraction. The powder was different sizes, and its surface displayed schistose shapes, rough and irregular cracks.The microstructure of lotus seed powder before and after extraction was significantly different.It indicated that the soluble polysaccharides could be extracted greatly from lotus seed powder using the optimized hot water extraction process.
Abstract：
To optimize the vacuum frying technological parameter of papaya chips and to provide theoretical basis for the development of papaya snack instant foods. Sensory evaluation factors included color, shape, crisp extents and greasy sense.Orthogonal test on the basis of single factor experiment was conducted to investigate the effect of vacuum frying temperature, frying time and vacuum degree on quality of papaya chips.The results showed that the weighting set of papaya chips based on sensory evaluation was K = ( color 0.26, shape 0.21, crisp extent 0.35, greasy sense 0.18) and the optimal technological condition was as follows: vacuum frying temperature 100 ℃, frying time 35 min, vacuum degree 0.09 MPa.Under this condition, the sensory evaluation level of papaya chips was excellent with the peak of 0.656. The product was especially crispy and delicious, as well as nutritious and easy to be accepted by consumers.Fuzzy mathematics applied to sensory evaluation greatly eliminated the effect of subjective factor on evaluation result, which made the evaluation result objective and accurate.
To optimize the vacuum frying technological parameter of papaya chips and to provide theoretical basis for the development of papaya snack instant foods. Sensory evaluation factors included color, shape, crisp extents and greasy sense.Orthogonal test on the basis of single factor experiment was conducted to investigate the effect of vacuum frying temperature, frying time and vacuum degree on quality of papaya chips.The results showed that the weighting set of papaya chips based on sensory evaluation was K = ( color 0.26, shape 0.21, crisp extent 0.35, greasy sense 0.18) and the optimal technological condition was as follows: vacuum frying temperature 100 ℃, frying time 35 min, vacuum degree 0.09 MPa.Under this condition, the sensory evaluation level of papaya chips was excellent with the peak of 0.656. The product was especially crispy and delicious, as well as nutritious and easy to be accepted by consumers.Fuzzy mathematics applied to sensory evaluation greatly eliminated the effect of subjective factor on evaluation result, which made the evaluation result objective and accurate.
Abstract：
Ginger was taken as main material in this study.The processing of sugar-infused ginger slices includes cooking, sugar infusing, drying and wrapping yam powder. The factors cooking time, sugar infusing time, and concentration of k-carrageenan were chosen to optimize processing of sugar-infused ginger slices by response surface methodology.The results showed that: the sensory evaluation score was 85.5 while ginger thickness, cooking time, concentration of k-carrageenan, sugar infusing time, drying temperature, drying time were 4 mm, 10 min, 1.2 mg/m L, 11 min, 60 ℃, 4 h.Using the physical device on texture profile analysis of the sugar-infused ginger slices, the hardness was 22731.70 N, the flexibility was 0.46 mm, the cohesiveness was0.45, the adhesive nature was 10527.90 N, chewiness was 5176.96 N·mm, and product sense perception was best.
Ginger was taken as main material in this study.The processing of sugar-infused ginger slices includes cooking, sugar infusing, drying and wrapping yam powder. The factors cooking time, sugar infusing time, and concentration of k-carrageenan were chosen to optimize processing of sugar-infused ginger slices by response surface methodology.The results showed that: the sensory evaluation score was 85.5 while ginger thickness, cooking time, concentration of k-carrageenan, sugar infusing time, drying temperature, drying time were 4 mm, 10 min, 1.2 mg/m L, 11 min, 60 ℃, 4 h.Using the physical device on texture profile analysis of the sugar-infused ginger slices, the hardness was 22731.70 N, the flexibility was 0.46 mm, the cohesiveness was0.45, the adhesive nature was 10527.90 N, chewiness was 5176.96 N·mm, and product sense perception was best.
2017, (18): 195-200.
DOI: 10.13386/j.issn1002-0306.2017.18.037
Abstract：
This study took walnut kernel as raw material and the technology of ultrasonic assisted alkali peeling was adopted.On the basis of single factor tests, the concentration of Na OH solution, ultrasonic temperature, alkali hot time and ultrasonic power were selected as the test factors, and peeling rate as examine index.The optimum process of walnut kernel peeling was optimized by using the response surface method. The test results showed that when the concentration of Na OH solution was 0.8%, ultrasonic temperature was 64 ℃, alkaline hot time was 4.5 min, ultrasonic power was 380 W, the average peeling rate of three tests was 5.46% ± 0.02%, and that the walnut peeling effect was the best, almost all of the skin could fall off after rinsing with water and the walnut had crisp texture and white color and no alkali flavor, which indicated that the optimized process was feasible.
This study took walnut kernel as raw material and the technology of ultrasonic assisted alkali peeling was adopted.On the basis of single factor tests, the concentration of Na OH solution, ultrasonic temperature, alkali hot time and ultrasonic power were selected as the test factors, and peeling rate as examine index.The optimum process of walnut kernel peeling was optimized by using the response surface method. The test results showed that when the concentration of Na OH solution was 0.8%, ultrasonic temperature was 64 ℃, alkaline hot time was 4.5 min, ultrasonic power was 380 W, the average peeling rate of three tests was 5.46% ± 0.02%, and that the walnut peeling effect was the best, almost all of the skin could fall off after rinsing with water and the walnut had crisp texture and white color and no alkali flavor, which indicated that the optimized process was feasible.
Abstract：
Co-precipitation protein was prepared from Tilapia muscle and defatted soybean meal by p H-shifting.Effect of p H value, mixing ratios of tilapia to defatted soybean meal, dissolving time on soluble protein yield was determined in the extraction process.And then effect of p H value on precipitated protein yield was examined as well.The results showed that the solubility of co-precipitation protein was best under the conditions of dissolution that the optimal p H value was 2.0, 3.0, 11.0, and 12.0, the tilapia to defatted soybean meal 1 ∶ 1, and the dissolving time of 30 min. The SDS-PAGE results showed that soluble co-precipitation protein bands of deep/shallow showed that the content of soluble co-precipitation protein of high/low ( protein degradation at p H2.0) .According to the distribution of molecular weight, it was found that the co-precipitation protein consisted mainly of myosin heavy chain, actin, myosin light chain, small molecule water soluble protein, three subunits of the antigen protein of 7 S and two subunits of the antigen protein of 11 S, which showed that the composition of soluble co-precipitation protein was complete.The precipitation condition of soluble co-precipitation protein was p H4.5.In the above four conditions, the recovered protein yields from tilapia muscle and soybean meal were 88.05% ~ 94.70% by acid/alkaline solubilization and precipitation processing.The co-precipitated protein powder, Co-p ( 1 ∶ 1) , was obtained by freeze-drying. The protein content was above 85%, the fat content was about 0.84%, and the ash content was less than 4.17%.The use of p H-shifting method was beneficial for the recovery of co-precipitated protein.
Co-precipitation protein was prepared from Tilapia muscle and defatted soybean meal by p H-shifting.Effect of p H value, mixing ratios of tilapia to defatted soybean meal, dissolving time on soluble protein yield was determined in the extraction process.And then effect of p H value on precipitated protein yield was examined as well.The results showed that the solubility of co-precipitation protein was best under the conditions of dissolution that the optimal p H value was 2.0, 3.0, 11.0, and 12.0, the tilapia to defatted soybean meal 1 ∶ 1, and the dissolving time of 30 min. The SDS-PAGE results showed that soluble co-precipitation protein bands of deep/shallow showed that the content of soluble co-precipitation protein of high/low ( protein degradation at p H2.0) .According to the distribution of molecular weight, it was found that the co-precipitation protein consisted mainly of myosin heavy chain, actin, myosin light chain, small molecule water soluble protein, three subunits of the antigen protein of 7 S and two subunits of the antigen protein of 11 S, which showed that the composition of soluble co-precipitation protein was complete.The precipitation condition of soluble co-precipitation protein was p H4.5.In the above four conditions, the recovered protein yields from tilapia muscle and soybean meal were 88.05% ~ 94.70% by acid/alkaline solubilization and precipitation processing.The co-precipitated protein powder, Co-p ( 1 ∶ 1) , was obtained by freeze-drying. The protein content was above 85%, the fat content was about 0.84%, and the ash content was less than 4.17%.The use of p H-shifting method was beneficial for the recovery of co-precipitated protein.
2017, (18): 207-210.
DOI: 10.13386/j.issn1002-0306.2017.18.039
Abstract：
Taking Moringa oleifera as the material, the polysaccharides were obtained by water extraction and alcohol precipitation.The acetylated Moringa oleifera polysaccharide derivatives were prepared by using acetic anhydride as acetylating agent. The technical conditions of acetylated modification were optimized with single factor experiment and orthogonal experiments, and the antioxidant activity was studied at the same time. The results indicated that the preparation optimal acetylated conditions for Moringa oleifera polysaccharides were as follows: reaction time 6 h, reaction temperature 60 ℃, acetylating reagent dosage 5 m L.The oxidation resistance research showed that the ability of removal hydroxyl free radicals and remove super oxide anion free radical ability were significantly enhanced.Acetylation could significantly improve the antioxidant activities of Moringa oleifera.
Taking Moringa oleifera as the material, the polysaccharides were obtained by water extraction and alcohol precipitation.The acetylated Moringa oleifera polysaccharide derivatives were prepared by using acetic anhydride as acetylating agent. The technical conditions of acetylated modification were optimized with single factor experiment and orthogonal experiments, and the antioxidant activity was studied at the same time. The results indicated that the preparation optimal acetylated conditions for Moringa oleifera polysaccharides were as follows: reaction time 6 h, reaction temperature 60 ℃, acetylating reagent dosage 5 m L.The oxidation resistance research showed that the ability of removal hydroxyl free radicals and remove super oxide anion free radical ability were significantly enhanced.Acetylation could significantly improve the antioxidant activities of Moringa oleifera.
Abstract：
The effects of the addition of purple potato powders on the baking loss rate, color difference, texture property and sensory quality of muffin cake were studied. The results showed that there were significant differences ( p < 0.05) in water solubility and water holding capacity of blended flour with different purple potato powders.The difference of baking loss rate was not significant ( p > 0.05) when the amount of purple powders was no more than 70%, but the difference was significant ( p < 0.05) when the amount of purple potato powders was 90%.The lightness of the muffin cake was significantly reduced with the increasing the amount of purple potato powders, but its hardness increased significantly with the increasing the amount of purple potato powders.When the amount of purple potato powders was 10% 30%, the changes of other texture indexes were not obvious ( p > 0.05) .The sensory evaluation muffin cake got the highest score when the amount of purple potato powers were 10%and 30%, respectively.The suitable amount of purple potato powders was 30%.
The effects of the addition of purple potato powders on the baking loss rate, color difference, texture property and sensory quality of muffin cake were studied. The results showed that there were significant differences ( p < 0.05) in water solubility and water holding capacity of blended flour with different purple potato powders.The difference of baking loss rate was not significant ( p > 0.05) when the amount of purple powders was no more than 70%, but the difference was significant ( p < 0.05) when the amount of purple potato powders was 90%.The lightness of the muffin cake was significantly reduced with the increasing the amount of purple potato powders, but its hardness increased significantly with the increasing the amount of purple potato powders.When the amount of purple potato powders was 10% 30%, the changes of other texture indexes were not obvious ( p > 0.05) .The sensory evaluation muffin cake got the highest score when the amount of purple potato powers were 10%and 30%, respectively.The suitable amount of purple potato powders was 30%.
2017, (18): 215-220.
DOI: 10.13386/j.issn1002-0306.2017.18.041
Abstract：
Solvent reflux method was used for saponins extraction and the responsive surface methodology was used to optimize the related parameters.Adsorption rate and desorption rate were used as indicators for screening of proper resin for saponins purification and determining of purification techniques. The obtained optimal extraction technique with a ratio ( bran to 72%ethanol) of 1∶ 20.8, carried out at 72 ℃ for 147 min, and the obtaining rate of saponins reached 1.685%. Compared with HPD600, S-8 and AB-8, the resin D101 showed the highest absorption rate and the highest desorption rate, so it was used for later purification studies. The results suggested that the highest absorption rate for D101 was obtained with a sample concentration of 4 mg/m L, the loading sample was adjusted to p H6 and loading at a velocity of 2 BV/h.The highest desorption rate was obtained when elute with 90% ethanol at a speed of 2 BV/h. The desorption fraction was condensed and freezing dried, the purity of resulted saponins powder reached 43.6%. The above results will facilitate the high-value application of quinoa bran and the related research work of quinoa saponins.
Solvent reflux method was used for saponins extraction and the responsive surface methodology was used to optimize the related parameters.Adsorption rate and desorption rate were used as indicators for screening of proper resin for saponins purification and determining of purification techniques. The obtained optimal extraction technique with a ratio ( bran to 72%ethanol) of 1∶ 20.8, carried out at 72 ℃ for 147 min, and the obtaining rate of saponins reached 1.685%. Compared with HPD600, S-8 and AB-8, the resin D101 showed the highest absorption rate and the highest desorption rate, so it was used for later purification studies. The results suggested that the highest absorption rate for D101 was obtained with a sample concentration of 4 mg/m L, the loading sample was adjusted to p H6 and loading at a velocity of 2 BV/h.The highest desorption rate was obtained when elute with 90% ethanol at a speed of 2 BV/h. The desorption fraction was condensed and freezing dried, the purity of resulted saponins powder reached 43.6%. The above results will facilitate the high-value application of quinoa bran and the related research work of quinoa saponins.
Abstract：
The adsorption and desorption of total flavonoids from lane late navel orange fruits were investigated by using 3macroporous resins.Results indicated that AB-8 resin was appropriate to purify the total flavonoids.Then the polyphenols from orange fruits were qualitatively and quantitatively by HPLC ( high performance liquid chromatography) . To optimize the separation process, the static and dynamic of adsorption and desorption experiments were carried out, the optimal adsorption conditions were as follows: initial concentrations in sample solution 0.75 mg/m L, p H3.0, sample loading amount 3.5 BV, flow rate 2 BV/h.The optimal desorption parameters were 80% ethanol 5 BV, flow rate of 2 BV/h, the desorption ratio was 90.73%.After purification, the content of flavonoids in product was increased from 36.04 mg/g to 334.54 mg/g. HPLC analysis results found that the flavonoids profiles of lane late navel orange were not changed after adsorption and desorption by AB-8macroporous resin. The main flavonoids were narirutin and hesperidin, the percentage content to the total flavonoids was91.14%. The results showed that AB-8 resin revealed a good ability to enrichment total flavonoids from lane late navel orange, and the method can be referenced for the enrichment of total flavonoids from other material.
The adsorption and desorption of total flavonoids from lane late navel orange fruits were investigated by using 3macroporous resins.Results indicated that AB-8 resin was appropriate to purify the total flavonoids.Then the polyphenols from orange fruits were qualitatively and quantitatively by HPLC ( high performance liquid chromatography) . To optimize the separation process, the static and dynamic of adsorption and desorption experiments were carried out, the optimal adsorption conditions were as follows: initial concentrations in sample solution 0.75 mg/m L, p H3.0, sample loading amount 3.5 BV, flow rate 2 BV/h.The optimal desorption parameters were 80% ethanol 5 BV, flow rate of 2 BV/h, the desorption ratio was 90.73%.After purification, the content of flavonoids in product was increased from 36.04 mg/g to 334.54 mg/g. HPLC analysis results found that the flavonoids profiles of lane late navel orange were not changed after adsorption and desorption by AB-8macroporous resin. The main flavonoids were narirutin and hesperidin, the percentage content to the total flavonoids was91.14%. The results showed that AB-8 resin revealed a good ability to enrichment total flavonoids from lane late navel orange, and the method can be referenced for the enrichment of total flavonoids from other material.
2017, (18): 226-231.
DOI: 10.13386/j.issn1002-0306.2017.18.043
Abstract：
The preservation effect of different composite natural antibacterial films ( blank control without film, sodium caseinate-chitosan-natamycin film, also named film M1, sodium caseinate-chitosan-natamycin/lysozyme film, also named film M2) on Cheddar cheese were studied. Sensory evaluation index, and moisture content, p H value, titratable acidity, soluble nitrogen content ( SN) , meltability, oil precipitation properties, textural properties, SDS-polyacrylamide gel electrophoresis ( SDS-PAGE) and microbial indexes of cheese in different storage time were measured under refrigeration at 4 ℃.The results showed that compared with the blank control, the sensory evaluation index, the physical and chemical indexes and textural properties of cheese packaged with film M1 and M2 were better, and the pattern of SDS-PAGE showed that the degree of proteolysis of cheese packaged with film M1 was relatively low, the colony counts ( 3.5 × 104CFU/m L) of the solution of cheese packaged with film M1 laying flat plate after 48 h were less than those ( 6.8 × 104CFU/m L and 9.2 × 104CFU/m L respectively) of the solution of cheese packaged with film M2 and the blank control under the same conditions.So film M1 was significantly better than film M2, and both of them had good antibacterial and preservation effects to effectively prolong storage period of Cheddar cheese.
The preservation effect of different composite natural antibacterial films ( blank control without film, sodium caseinate-chitosan-natamycin film, also named film M1, sodium caseinate-chitosan-natamycin/lysozyme film, also named film M2) on Cheddar cheese were studied. Sensory evaluation index, and moisture content, p H value, titratable acidity, soluble nitrogen content ( SN) , meltability, oil precipitation properties, textural properties, SDS-polyacrylamide gel electrophoresis ( SDS-PAGE) and microbial indexes of cheese in different storage time were measured under refrigeration at 4 ℃.The results showed that compared with the blank control, the sensory evaluation index, the physical and chemical indexes and textural properties of cheese packaged with film M1 and M2 were better, and the pattern of SDS-PAGE showed that the degree of proteolysis of cheese packaged with film M1 was relatively low, the colony counts ( 3.5 × 104CFU/m L) of the solution of cheese packaged with film M1 laying flat plate after 48 h were less than those ( 6.8 × 104CFU/m L and 9.2 × 104CFU/m L respectively) of the solution of cheese packaged with film M2 and the blank control under the same conditions.So film M1 was significantly better than film M2, and both of them had good antibacterial and preservation effects to effectively prolong storage period of Cheddar cheese.
Abstract：
The experiment was carried out with large yellow croaker, making trehalose, sorbitol and sodium into different mixed antifreezing agents and then compare the large yellow croaker's hardness and water holding capacity and soluble protein, Ca2+-ATPase's activity, sulfhydryl content, total sulfhydryl content, variation regularity of surface hydrophobicity.In addition, SDS-PAGE gel electrophoresis was performed after frozen storage of 35 d and then the degree of denaturation of surimi protein under different antifreeze agents was analyzed. The results showed that different cryoprotectants could inhibit the protein denaturation of large yellow croaker. Mixed trehalose, sorbitol, sodium citrate three anti freeze denaturation was better than sorbitol, sodium citrate used alone on large yellow croaker myofibrillar protein. The quality of fish meat was decreased slowly with the addition of trehalose, sorbitol and sodium citrate. The physicochemical properties of the protein were stable and the structure of fish protein changed slowly.
The experiment was carried out with large yellow croaker, making trehalose, sorbitol and sodium into different mixed antifreezing agents and then compare the large yellow croaker's hardness and water holding capacity and soluble protein, Ca2+-ATPase's activity, sulfhydryl content, total sulfhydryl content, variation regularity of surface hydrophobicity.In addition, SDS-PAGE gel electrophoresis was performed after frozen storage of 35 d and then the degree of denaturation of surimi protein under different antifreeze agents was analyzed. The results showed that different cryoprotectants could inhibit the protein denaturation of large yellow croaker. Mixed trehalose, sorbitol, sodium citrate three anti freeze denaturation was better than sorbitol, sodium citrate used alone on large yellow croaker myofibrillar protein. The quality of fish meat was decreased slowly with the addition of trehalose, sorbitol and sodium citrate. The physicochemical properties of the protein were stable and the structure of fish protein changed slowly.
Abstract：
An optimized method was developed for the determination of acid orangeⅡin soy sauce and pot-roast meat products by HPLC-SPE.Samples were firstly removed oil by petroleum, extracted by ammonia-ethanol-water solution (20∶70∶10 of volume ratio) , concentrated by water bath at 70℃, and adjusted p H value to 56.Then, the extraction was cleaned and enriched by Agela Cleanert WPAX weak anion exchange column.The elution was dried by water bath at 60℃and dissolved with water to a constant volume.Sample solution were separated by Thermo Hypersil Gold
An optimized method was developed for the determination of acid orangeⅡin soy sauce and pot-roast meat products by HPLC-SPE.Samples were firstly removed oil by petroleum, extracted by ammonia-ethanol-water solution (20∶70∶10 of volume ratio) , concentrated by water bath at 70℃, and adjusted p H value to 56.Then, the extraction was cleaned and enriched by Agela Cleanert WPAX weak anion exchange column.The elution was dried by water bath at 60℃and dissolved with water to a constant volume.Sample solution were separated by Thermo Hypersil Gold
2017, (18): 242-246.
DOI: 10.13386/j.issn1002-0306.2017.18.046
Abstract：
A method of inductively coupled plasma optical emission spectrometry ( ICP-OES) and inductively coupled plasma mass spectrometry ( ICP-MS) was established to determine 46 elements in Siraitia grosvenorii.The detection limit of ICP-OES and ICP-MS were in the range of 0.6818.10 μg/L and 0.001 0.093 μg/L, respectively.The precision of this method was in the range of 0.73% to 6.83%, and the recovery varied from 88.7% to 112.1%.The established method was used to determine the corresponding element content in the certified reference material of bush branch and leaf, which was in agreement with the certified values.The results showed that there were rich trace elements in Siraitia grosvenorii, 13 of which were more than2 mg/kg. The method was simple, rapid and accurate and suitable for the determination of multi-elements in Siraitia grosvenorii simultaneously.
A method of inductively coupled plasma optical emission spectrometry ( ICP-OES) and inductively coupled plasma mass spectrometry ( ICP-MS) was established to determine 46 elements in Siraitia grosvenorii.The detection limit of ICP-OES and ICP-MS were in the range of 0.6818.10 μg/L and 0.001 0.093 μg/L, respectively.The precision of this method was in the range of 0.73% to 6.83%, and the recovery varied from 88.7% to 112.1%.The established method was used to determine the corresponding element content in the certified reference material of bush branch and leaf, which was in agreement with the certified values.The results showed that there were rich trace elements in Siraitia grosvenorii, 13 of which were more than2 mg/kg. The method was simple, rapid and accurate and suitable for the determination of multi-elements in Siraitia grosvenorii simultaneously.
Abstract：
Near infrared reflectance spectroscopy technique was employed to measure the polysaccharides of Chinese herb extracts rapidly.The experiment had measured the content of polysaccharides in the 102 groups of the oral liquid of Chinese herb extracts, adopts the partial least squares method combined with the polysaccharides chemical reference values, and establishes the optimal model of measuring the polysaccharides of the oral liquid by the near infrared reflectance spectroscopy technique, which was obtained by comparing method and derivative of different preprocessing and the size, waveband and variable selection way of the smooth window on the predictive ability of the above model: the pre-processing method of spectrum wasthe combination of the first derivative and smooth process, and their moving window widths were 5 and 9respectively.The chosen wavebands contained 5079.58 ~ 5152.86, 6159.52 ~ 6232.80, 6545.21 ~ 6695.63, 7470.88 ~ 7544.16 and8705.09 8778.38 cm-1 in the sum of 120 variables.The root-mean-square error of the model cross validation was 15.4823, and the root-mean-square error of the model prediction was 16.2807.The results showed that the method for rapidly measuring the polysaccharides in oral liquid based on the combination of the near infrared reflectance spectroscopy technique and chemometrics method was of certain feasibility.
Near infrared reflectance spectroscopy technique was employed to measure the polysaccharides of Chinese herb extracts rapidly.The experiment had measured the content of polysaccharides in the 102 groups of the oral liquid of Chinese herb extracts, adopts the partial least squares method combined with the polysaccharides chemical reference values, and establishes the optimal model of measuring the polysaccharides of the oral liquid by the near infrared reflectance spectroscopy technique, which was obtained by comparing method and derivative of different preprocessing and the size, waveband and variable selection way of the smooth window on the predictive ability of the above model: the pre-processing method of spectrum wasthe combination of the first derivative and smooth process, and their moving window widths were 5 and 9respectively.The chosen wavebands contained 5079.58 ~ 5152.86, 6159.52 ~ 6232.80, 6545.21 ~ 6695.63, 7470.88 ~ 7544.16 and8705.09 8778.38 cm-1 in the sum of 120 variables.The root-mean-square error of the model cross validation was 15.4823, and the root-mean-square error of the model prediction was 16.2807.The results showed that the method for rapidly measuring the polysaccharides in oral liquid based on the combination of the near infrared reflectance spectroscopy technique and chemometrics method was of certain feasibility.
Abstract：
In oder to understand the characteristic properties of Ningxiang pork meat and related effects on the formation of specific aroma of air-dried sausage, 4 different parts of Ningxiang pork meat were used as raw material for the production of air-dried sausage.The volatile compounds from 4 different samples were extracted by solid-phase micro-extraction ( SPME) and analyzed by gas chromatography-mass spectrometry ( GC-MS) . A total of thirty-five volatile compounds were identified, including 2 types of alcohols, 18 aldehydes, 6 esters, 7 hydrocarbons, and 2 others. Among these compounds, the aldehydes, esters and hydrocarbons were most abundant in all 4 samples and played a leading rule for the formation of specific aroma in these products.Further analysis revealed that aldehydes and esters made the largest contribution to the formation of specific aroma in this kind of products.And its abundance was closely related to the relative high contents of unsaturated fatty acids in Ningxiang pork meat, such as oleic acid, linoleic acid and others. However, significant variations were detected among these 4different samples.
In oder to understand the characteristic properties of Ningxiang pork meat and related effects on the formation of specific aroma of air-dried sausage, 4 different parts of Ningxiang pork meat were used as raw material for the production of air-dried sausage.The volatile compounds from 4 different samples were extracted by solid-phase micro-extraction ( SPME) and analyzed by gas chromatography-mass spectrometry ( GC-MS) . A total of thirty-five volatile compounds were identified, including 2 types of alcohols, 18 aldehydes, 6 esters, 7 hydrocarbons, and 2 others. Among these compounds, the aldehydes, esters and hydrocarbons were most abundant in all 4 samples and played a leading rule for the formation of specific aroma in these products.Further analysis revealed that aldehydes and esters made the largest contribution to the formation of specific aroma in this kind of products.And its abundance was closely related to the relative high contents of unsaturated fatty acids in Ningxiang pork meat, such as oleic acid, linoleic acid and others. However, significant variations were detected among these 4different samples.
2017, (18): 258-263.
DOI: 10.13386/j.issn1002-0306.2017.18.049
Abstract：
The positions of tiny bruising apples are easily invaded by pathogenic microorganisms, causing themselves and surrounding fruits to rot.The early detection can effectively reduce the loss from tiny bruise.In this study, the single integrating sphere setup and the inverse adding-doubling ( IAD) method were used to investigate the optical properties of Fuji apples at14501800 nm.The data of optical properties were preprocessed by the multiplicative scatter correction and standard normal variables methods.A discriminate model that combines principal component analysis with Probabilistic neural networks ( PNN) to judge and predict the bruising of apples was established based on the absorption coefficient and the reduced scattering coefficient of 14501800 nm.The accuracy of the model for no bruising judgment was above 96%.The accuracy of the model of absorption coefficients for early bruising judgment was 100% when spread was less 0.7.The experimental results showed optical properties can judge the early tiny bruising of apples and provide application prospect of detecting the bruise of fruits.
The positions of tiny bruising apples are easily invaded by pathogenic microorganisms, causing themselves and surrounding fruits to rot.The early detection can effectively reduce the loss from tiny bruise.In this study, the single integrating sphere setup and the inverse adding-doubling ( IAD) method were used to investigate the optical properties of Fuji apples at14501800 nm.The data of optical properties were preprocessed by the multiplicative scatter correction and standard normal variables methods.A discriminate model that combines principal component analysis with Probabilistic neural networks ( PNN) to judge and predict the bruising of apples was established based on the absorption coefficient and the reduced scattering coefficient of 14501800 nm.The accuracy of the model for no bruising judgment was above 96%.The accuracy of the model of absorption coefficients for early bruising judgment was 100% when spread was less 0.7.The experimental results showed optical properties can judge the early tiny bruising of apples and provide application prospect of detecting the bruise of fruits.
Abstract：
The forchlorfenuron residues in soil were determined quickly by solid-phase extraction and ultra performance liquid chromatography ( SPE-UPLC) in this paper. And this paper compared to determine the appropriate pre-treatment methods, optimized the extraction method and purification conditions.The optimal conditions were obtained that the sample was extracted with acetonitrile for 30 min by ultrasonic method, centrifuged in 5000 r/min and cleaned up with the PSA column.Forchlorfenuron was determined by ultra performance liquid chromatography using acetonitrile-water ( 65 ∶ 35) as mobile phase.The developed method showed a good linear relationship in the range of 0.05 ~ 5.0 μg/m L for forchlorfenuron, with correlation coefficient of 0.9999.The limit of quantitation for forchlorfenuron was 0.025 mg/kg. The average recovery rates were78.34% 102.4%, with relative standard deviation ( RSD) ranging from 3.24% to 6.65%.The method is fast, highly sensitivity, repeatable and suitable for the determination of forchlorfenuron residues in soil.
The forchlorfenuron residues in soil were determined quickly by solid-phase extraction and ultra performance liquid chromatography ( SPE-UPLC) in this paper. And this paper compared to determine the appropriate pre-treatment methods, optimized the extraction method and purification conditions.The optimal conditions were obtained that the sample was extracted with acetonitrile for 30 min by ultrasonic method, centrifuged in 5000 r/min and cleaned up with the PSA column.Forchlorfenuron was determined by ultra performance liquid chromatography using acetonitrile-water ( 65 ∶ 35) as mobile phase.The developed method showed a good linear relationship in the range of 0.05 ~ 5.0 μg/m L for forchlorfenuron, with correlation coefficient of 0.9999.The limit of quantitation for forchlorfenuron was 0.025 mg/kg. The average recovery rates were78.34% 102.4%, with relative standard deviation ( RSD) ranging from 3.24% to 6.65%.The method is fast, highly sensitivity, repeatable and suitable for the determination of forchlorfenuron residues in soil.
Abstract：
Fixation and drying are the key process of the green tea aroma formation.1 bud 2, 3 fresh tea leaves of Camellia sinensis cv.Huang shn zhong were taken as experimental material, dried at 80, 110, 130 ℃, respectively, faint scent, chestnut flavor scent and high fire scent of green tea were got. Using headspace solid phase micro extraction ( HS-SPME) and gas chromatography/mass spectrometry ( GC-MS) , the aroma components and proportions were analyzed. And then aroma composition variability of fresh tea, enzym-denatured leaf and dry tea was learned.Experiment showed that fixation removed lots of ocimene, leaf acetate and some other ingredients which smell gramineous. High boiling aromatic substances in tea were increased during drying process.Tea dried at 80 ℃ contained relatively little aromatic components, showing faint scent.Tea dried at 110 ℃ produced phenylacetaldehyde and ethyl laurate and some more original aroma component, showing chestnut flavor scent.Tea dried at 130 ℃ produced high fire components, like pyrrole and pyrazine, showing high fire scent.So the temperature of drying affects the types and contents of aroma components, resulting in a variety of flavor types.
Fixation and drying are the key process of the green tea aroma formation.1 bud 2, 3 fresh tea leaves of Camellia sinensis cv.Huang shn zhong were taken as experimental material, dried at 80, 110, 130 ℃, respectively, faint scent, chestnut flavor scent and high fire scent of green tea were got. Using headspace solid phase micro extraction ( HS-SPME) and gas chromatography/mass spectrometry ( GC-MS) , the aroma components and proportions were analyzed. And then aroma composition variability of fresh tea, enzym-denatured leaf and dry tea was learned.Experiment showed that fixation removed lots of ocimene, leaf acetate and some other ingredients which smell gramineous. High boiling aromatic substances in tea were increased during drying process.Tea dried at 80 ℃ contained relatively little aromatic components, showing faint scent.Tea dried at 110 ℃ produced phenylacetaldehyde and ethyl laurate and some more original aroma component, showing chestnut flavor scent.Tea dried at 130 ℃ produced high fire components, like pyrrole and pyrazine, showing high fire scent.So the temperature of drying affects the types and contents of aroma components, resulting in a variety of flavor types.
2017, (18): 275-278.
DOI: 10.13386/j.issn1002-0306.2017.18.052
Abstract：
A flow injection spectrophotometry method for the determination of aldehydes content in vegetable oil was built.The standard substance was adopted by mixed equal-molar nine aldehydes ( formaldehyde, acetaldehyde, n-propanal, n-butanal, n-pentanal, n-hexaldehyde, n-heptaldehyde, n-octanal and n-nonanal) . The optimal condition for aldehydes determination was obtained by adjusting catalysts, temperature, time, solvents, flow rate, and dosage of reagent, which was suitable to the reaction of aldehydes and 2-naphthylhydrazine to produce the 2-naphthalene hydrazone derivatives under the acid action by self-made flow injection equipment with strong fluorescence-emission at 400 nm. As a result, the linear equation of aliphatic aldehydes was y = 26.8x + 42 ( r = 0.997) , with 1.18% ~ 1.89% of relative standard deviation ( RSD) and 92% ~ 113% of recovery rate.The limit of detection ( LOD) for this method was 0.02 mmol/L ( S/N = 3) .The method can be applied successfully to the determination of aliphatic aldehydes in plant oils with much simple way, high speed and accuracy.
A flow injection spectrophotometry method for the determination of aldehydes content in vegetable oil was built.The standard substance was adopted by mixed equal-molar nine aldehydes ( formaldehyde, acetaldehyde, n-propanal, n-butanal, n-pentanal, n-hexaldehyde, n-heptaldehyde, n-octanal and n-nonanal) . The optimal condition for aldehydes determination was obtained by adjusting catalysts, temperature, time, solvents, flow rate, and dosage of reagent, which was suitable to the reaction of aldehydes and 2-naphthylhydrazine to produce the 2-naphthalene hydrazone derivatives under the acid action by self-made flow injection equipment with strong fluorescence-emission at 400 nm. As a result, the linear equation of aliphatic aldehydes was y = 26.8x + 42 ( r = 0.997) , with 1.18% ~ 1.89% of relative standard deviation ( RSD) and 92% ~ 113% of recovery rate.The limit of detection ( LOD) for this method was 0.02 mmol/L ( S/N = 3) .The method can be applied successfully to the determination of aliphatic aldehydes in plant oils with much simple way, high speed and accuracy.
Abstract：
Effects of slightly acidic electrolyzed water ( SAEW) in combination with 1% Ca (NO3) 2 on fruit firmness, sensory scores, decay incidence, relative electrical conductivity, and juice yield were investigated in the ‘Okubao 'peach. The cell structure and contents of Ca2+ and K+were monitored by scanning electron microscopy and X-ray energy spectra intensity.Furthermore, water mobility was analyzed by the low-field nuclear magnetic resonance. Results showed that the combined treatment was the most effective than SAEW or Ca (NO3) 2 treatment alone, which significantly inhibited the decrease of fruit firmness and taste score, reduced decay incidence and the increase of cell membrane permeability, promoted Ca2+ absorption, stabilized cell wall and membrane system and extra-cellular water, inhibited the loss of intra-and extra-cellular water, maintained the higher quality.
Effects of slightly acidic electrolyzed water ( SAEW) in combination with 1% Ca (NO3) 2 on fruit firmness, sensory scores, decay incidence, relative electrical conductivity, and juice yield were investigated in the ‘Okubao 'peach. The cell structure and contents of Ca2+ and K+were monitored by scanning electron microscopy and X-ray energy spectra intensity.Furthermore, water mobility was analyzed by the low-field nuclear magnetic resonance. Results showed that the combined treatment was the most effective than SAEW or Ca (NO3) 2 treatment alone, which significantly inhibited the decrease of fruit firmness and taste score, reduced decay incidence and the increase of cell membrane permeability, promoted Ca2+ absorption, stabilized cell wall and membrane system and extra-cellular water, inhibited the loss of intra-and extra-cellular water, maintained the higher quality.
2017, (18): 285-289.
DOI: 10.13386/j.issn1002-0306.2017.18.054
Abstract：
Five typical varieties were selected to study the storage characteristics in different varieties of spinach in the Beijing area.Spinach were King of disease-resistant, Nongda bo's miscellaneous 1, Nongda bo's miscellaneous 10, Pioneer, Japanese big leaf, and the quality change had been studied in the storage period.Indices were sensory evaluation, the weightlessness rate, conductivity, vitamin C content, chlorophyll content, activity of peroxidase, polyphenol oxidase activity. Regard 5 score as the commercial limit, on the 11 th day, only Nongda bo's miscellaneous' s sensory evaluation was not less than five points, Japanese big leaf's sensory score was 5 on the 7th day and lost the commercial, Japanese big leaf's weightlessness rate was maximum, reached up to 23.14%, and the Nongda bo's miscellaneous 1 's weightlessness rate was minimum, at 10.78%. The vitamin C content of Japanese big leaf reduced mostly, and was 75.26%.The vitamin C content of Nongda bo's miscellaneous 1 reduced least, as much as 52.74%. Comprehensive evaluation of various indicators, five different varieties of spinach were resistant to storage quality in the order of: Nongda bo's miscellaneous 1 > Nongda bo's miscellaneous 10 > Japanese big leaf > King of disease-resistant > Pioneer.
Five typical varieties were selected to study the storage characteristics in different varieties of spinach in the Beijing area.Spinach were King of disease-resistant, Nongda bo's miscellaneous 1, Nongda bo's miscellaneous 10, Pioneer, Japanese big leaf, and the quality change had been studied in the storage period.Indices were sensory evaluation, the weightlessness rate, conductivity, vitamin C content, chlorophyll content, activity of peroxidase, polyphenol oxidase activity. Regard 5 score as the commercial limit, on the 11 th day, only Nongda bo's miscellaneous' s sensory evaluation was not less than five points, Japanese big leaf's sensory score was 5 on the 7th day and lost the commercial, Japanese big leaf's weightlessness rate was maximum, reached up to 23.14%, and the Nongda bo's miscellaneous 1 's weightlessness rate was minimum, at 10.78%. The vitamin C content of Japanese big leaf reduced mostly, and was 75.26%.The vitamin C content of Nongda bo's miscellaneous 1 reduced least, as much as 52.74%. Comprehensive evaluation of various indicators, five different varieties of spinach were resistant to storage quality in the order of: Nongda bo's miscellaneous 1 > Nongda bo's miscellaneous 10 > Japanese big leaf > King of disease-resistant > Pioneer.
Abstract：
Jiashi muskmelon and 86-1 muskmelon species with the characteristics of disease resistance were used as experiment material.This study was aimed to the activities of CHT, GLU and the gene expression rules for CHT and GLU in muskmelon fruits inoculated with A.alternata were analyzed.Jiashi muskmelon and 86-1 muskmelon were inoculated with 20 μL A.alternata spore suspension, inoculation with 20 μL of sterile water as a blank control, the materials were transferred to cold storage at68 ℃, determination of lesion size, the activities of CHT, GLU and the gene expression of CHT and GLU.The results showed that the incidence and the lesion size of Jiashi muskmelon were lower than that of 86-1 muskmelon during the inoculated with A.alternata after 15 days.During the infection period, the activities of CHT, GLU was significantly increased with a trend from rise to decline. The peak of activities for CHT, GLU revealed of 21 d, 18 d. The activities of CHT, GLU in Jiashi melon significantly higher than 86-1 muskmelon Jiashi muskmelon to resist the infection of A.alternaria by enhancing the activity of protease and maintaining the enzyme activity at a higher level. The relative expressions for CHT1, CHT2, GLU were higher in Jiashi muskmelon than 86-1 muskmelon during the whole infection period.The expression levels of CHT1, CHT2 and GLU were significantly higher than 86-1 melon, and the expression level of CHT1, CHT2 and GLU was the highest in storage at 18, 18 and15 days.The relative expression of protein-related protein and gene expression were positively correlated with lesion diameter for 021 d.These results suggest that the pathogenesis related proteins play a key role in the early and middle stage of plant pathogen resistance.
Jiashi muskmelon and 86-1 muskmelon species with the characteristics of disease resistance were used as experiment material.This study was aimed to the activities of CHT, GLU and the gene expression rules for CHT and GLU in muskmelon fruits inoculated with A.alternata were analyzed.Jiashi muskmelon and 86-1 muskmelon were inoculated with 20 μL A.alternata spore suspension, inoculation with 20 μL of sterile water as a blank control, the materials were transferred to cold storage at68 ℃, determination of lesion size, the activities of CHT, GLU and the gene expression of CHT and GLU.The results showed that the incidence and the lesion size of Jiashi muskmelon were lower than that of 86-1 muskmelon during the inoculated with A.alternata after 15 days.During the infection period, the activities of CHT, GLU was significantly increased with a trend from rise to decline. The peak of activities for CHT, GLU revealed of 21 d, 18 d. The activities of CHT, GLU in Jiashi melon significantly higher than 86-1 muskmelon Jiashi muskmelon to resist the infection of A.alternaria by enhancing the activity of protease and maintaining the enzyme activity at a higher level. The relative expressions for CHT1, CHT2, GLU were higher in Jiashi muskmelon than 86-1 muskmelon during the whole infection period.The expression levels of CHT1, CHT2 and GLU were significantly higher than 86-1 melon, and the expression level of CHT1, CHT2 and GLU was the highest in storage at 18, 18 and15 days.The relative expression of protein-related protein and gene expression were positively correlated with lesion diameter for 021 d.These results suggest that the pathogenesis related proteins play a key role in the early and middle stage of plant pathogen resistance.
Abstract：
To evaluate the effect of sodium hypochlorite disinfection combined with polyvinyl alcohol-based composite packaging material with nano-SiO2 coating on fresh-keeping of duck eggs, the fresh eggs were treated by sodium hypochlorite disinfection, polyvinyl alcohol-based composite packaging material with nano-SiO2 coating, and sodium hypochlorite disinfection combined with polyvinyl alcohol-based composite packaging material with nano-SiO2 coating. All the duck eggs were stored at the same condition for 35 days and the changes of weight loss rate, total plate count, Hough units and yolk index value of duck eggs in each group were detected during storage process.The changes of the eggshell color and texture properties of duck eggs by three fresh-keeping treatments were also detected after storage. The results revealed that the weight loss rate and total plate count of duck eggs in three fresh-keeping groups were significantly decreased in comparison with control group ( p < 0.05) , and the disinfection combined with coating showed the lowest weight loss rate ( 2.79% ± 0.19%) and total platecount ( 4.83 ± 0.42) lg cfu/g. The Hough units and yolk index value of duck eggs in three fresh-keeping groups were significantly increased in comparison with control group ( p < 0.05) , and the disinfection combined with coating showed the highest Hough units ( 76.09 ± 4.15) and yolk index value ( 0.40 ± 0.02) , with no obvious difference to the fresh eggs before storage.In addition, the texture properties of eggs treated by disinfection combined with coating showed no significant difference relative to control group ( p > 0.05) , but the brightness was notably improved ( p < 0.05) .In conclusion, the three fresh-keeping treatments were significantly reversed the decline of the quality of duck eggs in comparison with control group ( p < 0.05) .To be mentioned, sodium hypochlorite disinfection combined with polyvinyl alcohol-based composite packaging material with nanoSiO2 coating exhibited the best fresh-keeping effect, which was significantly better than treated by sodium hypochlorite disinfection and polyvinyl alcohol-based composite packaging material with nano-SiO2 coating alone ( p < 0.05) . This study might provide reference for the application of disinfection combined with composite packaging material coating in the preservation of fresh eggs.
To evaluate the effect of sodium hypochlorite disinfection combined with polyvinyl alcohol-based composite packaging material with nano-SiO2 coating on fresh-keeping of duck eggs, the fresh eggs were treated by sodium hypochlorite disinfection, polyvinyl alcohol-based composite packaging material with nano-SiO2 coating, and sodium hypochlorite disinfection combined with polyvinyl alcohol-based composite packaging material with nano-SiO2 coating. All the duck eggs were stored at the same condition for 35 days and the changes of weight loss rate, total plate count, Hough units and yolk index value of duck eggs in each group were detected during storage process.The changes of the eggshell color and texture properties of duck eggs by three fresh-keeping treatments were also detected after storage. The results revealed that the weight loss rate and total plate count of duck eggs in three fresh-keeping groups were significantly decreased in comparison with control group ( p < 0.05) , and the disinfection combined with coating showed the lowest weight loss rate ( 2.79% ± 0.19%) and total platecount ( 4.83 ± 0.42) lg cfu/g. The Hough units and yolk index value of duck eggs in three fresh-keeping groups were significantly increased in comparison with control group ( p < 0.05) , and the disinfection combined with coating showed the highest Hough units ( 76.09 ± 4.15) and yolk index value ( 0.40 ± 0.02) , with no obvious difference to the fresh eggs before storage.In addition, the texture properties of eggs treated by disinfection combined with coating showed no significant difference relative to control group ( p > 0.05) , but the brightness was notably improved ( p < 0.05) .In conclusion, the three fresh-keeping treatments were significantly reversed the decline of the quality of duck eggs in comparison with control group ( p < 0.05) .To be mentioned, sodium hypochlorite disinfection combined with polyvinyl alcohol-based composite packaging material with nanoSiO2 coating exhibited the best fresh-keeping effect, which was significantly better than treated by sodium hypochlorite disinfection and polyvinyl alcohol-based composite packaging material with nano-SiO2 coating alone ( p < 0.05) . This study might provide reference for the application of disinfection combined with composite packaging material coating in the preservation of fresh eggs.
2017, (18): 300-305.
DOI: 10.13386/j.issn1002-0306.2017.18.057
Abstract：
In order to evaluate the nutritional value of loach in Taiwan, the general nutritional composition, the amino acids and fatty acids composition in muscle of loach in Taiwan were determined using the national standard method, the rate of flesh content and muscle water holding capacity were determined using the usual method.The results were as follows: the rate of flesh content of loach in Taiwan was 63.94% ± 7.76% and the edible part was 72.02% ± 2.91%. Muscle storage loss rate, frozen seepage rate, cooking weightlessness rate were 4.70% ± 0.41%, 11.66% ± 5.87%, 23.10% ± 5.98% respectively.The moisture of muscle, crude protein, crude fat and crude ash were 77.71% ± 0.59%, 17.93% ± 0.65%, 3.04% ± 0.62%, 1.24% ± 0.33%respectively.In the muscle of loach in Taiwan, there were 18 amino acids including eight essential amino acids and five delicious amino acids for human.The total amino acids, total essential amino acids and delicious amino acids were 82.82% ±2.58%, 33.11% ± 1.46%, 35.28% ± 0.88% respectively. According to the amino acid score, the first restrictive amino acid of loach in Taiwan was valine, and the second restrictive amino acid was tryptophan. According to the chemical score, the first restrictive amino acid was tryptophan, and the second restrictive amino acid was valine. The essential amino acid index was75.77. There were 23 fatty acids in the muscles.The content of polyunsaturated fatty acids ( PUFAs) was 37.85% ± 0.64%. The total content of eicosapntemacnioc acid ( EPA) and docosahexaenoic acid ( DHA) was 5.18% ± 1.23%.loach in Taiwan is a good source of protein and delicious taste freshwater fish with high nutrition.
In order to evaluate the nutritional value of loach in Taiwan, the general nutritional composition, the amino acids and fatty acids composition in muscle of loach in Taiwan were determined using the national standard method, the rate of flesh content and muscle water holding capacity were determined using the usual method.The results were as follows: the rate of flesh content of loach in Taiwan was 63.94% ± 7.76% and the edible part was 72.02% ± 2.91%. Muscle storage loss rate, frozen seepage rate, cooking weightlessness rate were 4.70% ± 0.41%, 11.66% ± 5.87%, 23.10% ± 5.98% respectively.The moisture of muscle, crude protein, crude fat and crude ash were 77.71% ± 0.59%, 17.93% ± 0.65%, 3.04% ± 0.62%, 1.24% ± 0.33%respectively.In the muscle of loach in Taiwan, there were 18 amino acids including eight essential amino acids and five delicious amino acids for human.The total amino acids, total essential amino acids and delicious amino acids were 82.82% ±2.58%, 33.11% ± 1.46%, 35.28% ± 0.88% respectively. According to the amino acid score, the first restrictive amino acid of loach in Taiwan was valine, and the second restrictive amino acid was tryptophan. According to the chemical score, the first restrictive amino acid was tryptophan, and the second restrictive amino acid was valine. The essential amino acid index was75.77. There were 23 fatty acids in the muscles.The content of polyunsaturated fatty acids ( PUFAs) was 37.85% ± 0.64%. The total content of eicosapntemacnioc acid ( EPA) and docosahexaenoic acid ( DHA) was 5.18% ± 1.23%.loach in Taiwan is a good source of protein and delicious taste freshwater fish with high nutrition.
Abstract：
The morbidity of peanut allergy around the world is relatively high, and for now there is no effective treatment.In this paper, the allergen detection and desensitization processing methods were reviewed.Desensitization and treatment methods were also reviewed in this paper, which would provide reference for the development of low-sensitized peanut products and desensitization methods.
The morbidity of peanut allergy around the world is relatively high, and for now there is no effective treatment.In this paper, the allergen detection and desensitization processing methods were reviewed.Desensitization and treatment methods were also reviewed in this paper, which would provide reference for the development of low-sensitized peanut products and desensitization methods.
2017, (18): 312-316.
DOI: 10.13386/j.issn1002-0306.2017.18.059
Abstract：
Bacillus expression system as gene engineering expression system has many advantages such as excellent secretion ability, successful heterologous protein expression system, not forming inclusion bodies, non-endotoxin, so it is widely studied and applied, many kinds of industrial enzymes were expressed in Bacillus subtilis expression system. In this review, it mainly talks about the advances, characters and application of Bacillus expression system, and presents a solution to the defects in the expression system of Bacillus, offering the main research directions for Bacillus expression system.
Bacillus expression system as gene engineering expression system has many advantages such as excellent secretion ability, successful heterologous protein expression system, not forming inclusion bodies, non-endotoxin, so it is widely studied and applied, many kinds of industrial enzymes were expressed in Bacillus subtilis expression system. In this review, it mainly talks about the advances, characters and application of Bacillus expression system, and presents a solution to the defects in the expression system of Bacillus, offering the main research directions for Bacillus expression system.
Abstract：
In this paper, the mechanism for gel formation of protein treated by microwave was studied and the major factors influencing the gel properties of food protein in microwave field were analyzed involving the protein type, microwave time, microwave power, additives and p H value etc. The effects of microwave on the change of molecular spatial structure of the protein were deeply summarized. Application of microwave in food protein was summarized. Moreover, the directions of microwave technology for the future development were proposed.
In this paper, the mechanism for gel formation of protein treated by microwave was studied and the major factors influencing the gel properties of food protein in microwave field were analyzed involving the protein type, microwave time, microwave power, additives and p H value etc. The effects of microwave on the change of molecular spatial structure of the protein were deeply summarized. Application of microwave in food protein was summarized. Moreover, the directions of microwave technology for the future development were proposed.
2017, (18): 323-327.
DOI: 10.13386/j.issn1002-0306.2017.18.061
Abstract：
Nutritional diseases are caused by the imbalance of nutrients, which led to a class or several types of metabolic abnormalities, particularly to the abnormality of lipid metabolism, glucose metabolism and amino acid metabolism. Thus, the timely measurement of metabolic profiles could help to prevent nutritional diseases. Targeted metabonomics is a powerful approach that simultaneously measures the low-molecular-weight endogenous metabolites, which could characterize the metabolic status of a biological system. This paper had reviewed the progress of targeted metabolomics techniques and their application in exploration of metabolic characteristics of obesity, diabetes mellitus, cardiovascular disease and other nutritional diseases.It was aimed to provide new ideas and theoretical basis for finding effective ways to prevent nutritional diseases.
Nutritional diseases are caused by the imbalance of nutrients, which led to a class or several types of metabolic abnormalities, particularly to the abnormality of lipid metabolism, glucose metabolism and amino acid metabolism. Thus, the timely measurement of metabolic profiles could help to prevent nutritional diseases. Targeted metabonomics is a powerful approach that simultaneously measures the low-molecular-weight endogenous metabolites, which could characterize the metabolic status of a biological system. This paper had reviewed the progress of targeted metabolomics techniques and their application in exploration of metabolic characteristics of obesity, diabetes mellitus, cardiovascular disease and other nutritional diseases.It was aimed to provide new ideas and theoretical basis for finding effective ways to prevent nutritional diseases.
2017, (18): 328-332.
DOI: 10.13386/j.issn1002-0306.2017.18.062
Abstract：
Grape polyphenols are important natural antioxidants in human diet, but its utilization in food industry is limited because of its low water solubility and easy degradation to various external environmental factors.Microencapsulation technology is a new technology which can encapsulate bioactive into carriers and helps to deliver it to the target sites, thereby to improve its bioavailability.Nowadays, microencapsulation technology has aroused great interest in the stabilization of grape polyphenols.In this paper, the latest research progress on microencapsulation of grape polyphenols was reviewed, the existing problems in the research field and the research prospect was also elaborated in order to lay a basis for the scientific research of the stabilization improvement of grape polyphenols in the future.
Grape polyphenols are important natural antioxidants in human diet, but its utilization in food industry is limited because of its low water solubility and easy degradation to various external environmental factors.Microencapsulation technology is a new technology which can encapsulate bioactive into carriers and helps to deliver it to the target sites, thereby to improve its bioavailability.Nowadays, microencapsulation technology has aroused great interest in the stabilization of grape polyphenols.In this paper, the latest research progress on microencapsulation of grape polyphenols was reviewed, the existing problems in the research field and the research prospect was also elaborated in order to lay a basis for the scientific research of the stabilization improvement of grape polyphenols in the future.
2017, (18): 333-340.
DOI: 10.13386/j.issn1002-0306.2017.18.063
Abstract：
Omics technologies including genomics, transcriptomics, proteomics, metabolomics and etc., have characteristics with high-throughput, high sensitivity and systematic.They provided powerful tools in life science research.Omics technologies have been broadly applied in tea science, and provided novel theoretical basis and approaches to study on tea cultivation and breeding, tea germplasm resources of tea plant, physiology and biochemistry of tea plant and tea processing of tea plant.In this work, the progress of researches by omics technology in tea science was reviewed.
Omics technologies including genomics, transcriptomics, proteomics, metabolomics and etc., have characteristics with high-throughput, high sensitivity and systematic.They provided powerful tools in life science research.Omics technologies have been broadly applied in tea science, and provided novel theoretical basis and approaches to study on tea cultivation and breeding, tea germplasm resources of tea plant, physiology and biochemistry of tea plant and tea processing of tea plant.In this work, the progress of researches by omics technology in tea science was reviewed.
2017, (18): 341-346.
DOI: 10.13386/j.issn1002-0306.2017.18.064
Abstract：
In the past few years, with people's cognition of their nutritional function the consumption of fresh and fresh-cut produces has increased sturdily.In order to adopt to this trend, it is an important way to develop effective post harvest storage and packaging technology, in addition to increasing production. Modified atmosphere packaging ( MAP) possesses a potential to become one of the most appropriate technologies, it has advantages of extending the shelf-life, preserving or stabilizing the desired properties of fresh produces, and convenience in handing and distribution.The success of MAP-fresh foods depends on many factors including types of fresh foods, storage temperature and humidity, gas composition, and the characteristics of package materials.This paper reviewed the recent developments highlighting the antioxidant active film, the nano packaging film and the biodegradable film.Although the innovations and development of food packaging technology will continue to promote the development of novel MAP, concentrated research and endeavors from scientists and engineers are still important to the development of MAP that focuses on consumers' requirements, enhancing product quality, environmental friendly design, and cost-effective application.
In the past few years, with people's cognition of their nutritional function the consumption of fresh and fresh-cut produces has increased sturdily.In order to adopt to this trend, it is an important way to develop effective post harvest storage and packaging technology, in addition to increasing production. Modified atmosphere packaging ( MAP) possesses a potential to become one of the most appropriate technologies, it has advantages of extending the shelf-life, preserving or stabilizing the desired properties of fresh produces, and convenience in handing and distribution.The success of MAP-fresh foods depends on many factors including types of fresh foods, storage temperature and humidity, gas composition, and the characteristics of package materials.This paper reviewed the recent developments highlighting the antioxidant active film, the nano packaging film and the biodegradable film.Although the innovations and development of food packaging technology will continue to promote the development of novel MAP, concentrated research and endeavors from scientists and engineers are still important to the development of MAP that focuses on consumers' requirements, enhancing product quality, environmental friendly design, and cost-effective application.
Abstract：
Zanthoxylum was one of the most resourceful spice in China.Hemp flavor material ( pepper amide) was an important component of the unique flavor of Zanthoxylum bungeanum, which directly determined the degree of pungent hemp and was an important factor affecting the quality of Zanthoxylum bungeanum. The extractive of Zanthoxylum which had numerous physiological fuctions such as anesthesia, excitement, bacterial inhibition, rheumatism relieving, analgesic and desinsection, was widely used in the field of food, medicine and agriculture.This article was an overview of the sensory grading and detection of Zanthoxylum, and prospected the development trend of the future.
Zanthoxylum was one of the most resourceful spice in China.Hemp flavor material ( pepper amide) was an important component of the unique flavor of Zanthoxylum bungeanum, which directly determined the degree of pungent hemp and was an important factor affecting the quality of Zanthoxylum bungeanum. The extractive of Zanthoxylum which had numerous physiological fuctions such as anesthesia, excitement, bacterial inhibition, rheumatism relieving, analgesic and desinsection, was widely used in the field of food, medicine and agriculture.This article was an overview of the sensory grading and detection of Zanthoxylum, and prospected the development trend of the future.
