Identification of A1/A2 <i>β</i>-Casein Genotypes and Comparison of Their Digestive Properties

LI Shihang; XU Hongtao; LI Xiao; SUN Meiling; YANG Xinyan; XIANG Pengyu; YANG Zhihao; MAN Chaoxin; JIANG Yujun

doi:10.13386/j.issn1002-0306.2024040342

Volume 46 Issue 5

Feb. 2025

Turn off MathJax

Article Contents

Abstract

References

Supplements

Science and Technology of Food Industry > 2025 > 46(5): 160-167. > DOI: 10.13386/j.issn1002-0306.2024040342

LI Shihang, XU Hongtao, LI Xiao, et al. Identification of A1/A2 β-Casein Genotypes and Comparison of Their Digestive Properties[J]. Science and Technology of Food Industry, 2025, 46(5): 160−167. (in Chinese with English abstract). doi: 10.13386/j.issn1002-0306.2024040342.

Citation:

PDF (7645 KB)

Identification of A1/A2 β-Casein Genotypes and Comparison of Their Digestive Properties

1.
Key Lab of Dairy Science, Ministry of Education, College of Food Science, Northeast Agricultural University, Harbin 150030, China
2.
Hangzhou Chaomu Electronic Commerce Company Limited, Hangzhou 311000, China

More Information

Received Date: April 22, 2024
Available Online: December 28, 2024

Graphical Abstract

Abstract

Abstract

A1 β-casein and A2 β-casein produce different substances after digestion due to differences in primary structure. To more comprehensively explore the possible biological activity effects on the human body, by analyzing and monitoring the changes of this protein during the digestion process, the exploration of the biological functions of A1/A2 β-casein is further achieved. In this study, allele-specific PCR was initially performed on milk samples collected from different cows in the pasture to identify A1 and A2 milk types. Afterwards, β-casein isolated from A1 and A2 milk was purified and characterized with the help of anion exchange chromatography and sodium dodecyl sulfate polyacrylamide gel electrophoresis. Finally, a static in vitro digestion model was constructed to compare A1 and A2 β-casein in terms of digestive properties. The results showed that the concentrations of isolated and purified A1 and A2 β-casein were 0.62 mg/mL and 0.66 mg/mL and the purities were 95.28% and 96.60%. After 5.0 h of static in vitro simulated digestion, the final digestibility of both β-caseins was around 90%, and the difference was not significant. A2 β-casein exhibited a higher degree of hydrolysis of 25.34% from the beginning of the intestinal digestion phase until the end of digestion. With the increase of gastrointestinal digestion time, the particle size of the two β-caseins decreased and the absolute value of the potential increased, and the degree of change in particle size and potential was greater for A2 β-casein than for A1 β-casein. In conclusion, the present study revealed the differences in the physicochemical properties of A1 and A2 β-caseins during static in vitro digestion and indicated to some extent that A2 β-caseins might have better digestive properties than A1 β-caseins, which provided a certain scientific basis for further expanding the application of A2 β-caseins in dairy products.
- A1 β-casein,
- A2 β-casein,
- allele-specific PCR,
- in vitro mock digestion,
- digestive properties

FullText(HTML)

References (34)

References

[1]	GIGLIOTI R, OKINO C H, AZEVEDO B T, et al. Novel LNA probe-based assay for the A1 and A2 identification of β-casein gene in milk samples[J]. Food Chemistry:Molecular Sciences,2021,3:100055.
[2]	CHEN X Q, FAN R, WANG Y B, et al. Bovine milk β-casein:Structure, properties, isolation, and targeted application of isolated products[J]. Comprehensive Reviews in Food Science and Food Safety,2024,23(2):e13311. doi: 10.1111/1541-4337.13311
[3]	SUN Y L, DING Y X, LIU B Q, et al. Recent advances in the bovine β-casein gene mutants on functional characteristics and nutritional health of dairy products:Status, challenges, and prospects[J]. Food Chemistry,2024,443:138510. doi: 10.1016/j.foodchem.2024.138510
[4]	OSMAN A, ZUFFA S, WALTON G, et al. Post-weaning A1/A2 β-casein milk intake modulates depressive-like behavior, brain μ-opioid receptors, and the metabolome of rats[J]. Iscience,2021,24(9):103048. doi: 10.1016/j.isci.2021.103048
[5]	陈龙, 付王艳, 方琼燕, 等. 牛乳中β-酪蛋白基因分型及β-酪啡肽-7的研究进展[J]. 中国乳品工业,2019,47(8):29−34. [CHEN L, FU W Y, FANG Q Y, et al. Recent advances of β-casein genotyping in bovine milk and potential impact of β-casomorphin-7 on human health[J]. China Dairy Industry,2019,47(8):29−34.] doi: 10.3969/j.issn.1001-2230.2019.08.007 CHEN L, FU W Y, FANG Q Y, et al. Recent advances of β-casein genotyping in bovine milk and potential impact of β-casomorphin-7 on human health[J]. China Dairy Industry, 2019, 47（8）: 29−34. doi: 10.3969/j.issn.1001-2230.2019.08.007
[6]	DE VASCONCELOS M L, OLIVEIRA L M F S, HILL J P, et al. Difficulties in establishing the adverse effects of β-casomorphin-7 released from β-casein variants—A review[J]. Foods,2023,12(17):3151. doi: 10.3390/foods12173151
[7]	CHIA J S J, MCRAE J L, KUKULJAN S, et al. A1 beta-casein milk protein and other environmental pre-disposing factors for type 1 diabetes[J]. Nutrition & Diabetes,2017,7(5):e274.
[8]	LI X, LU X R, LIU M, et al. The immunomodulatory effects of A2 β-casein on immunosuppressed mice by regulating immune responses and the gut microbiota[J]. Nutrients,2024,16(4):519. doi: 10.3390/nu16040519
[9]	BROOKE-TAYLOR S, DWYER K, WOODFORD K, et al. Systematic review of the gastrointestinal effects of A1 compared with A2 β-casein[J]. Advances in Nutrition,2017,8(5):739−748. doi: 10.3945/an.116.013953
[10]	CATTANEO S, MASOTTI F, STUKNYTE M, et al. Impact of in vitro static digestion method on the release of β-casomorphin-7 from bovine milk and cheeses with A1 or A2 β-casein phenotypes[J]. Food Chemistry,2023,404:134617. doi: 10.1016/j.foodchem.2022.134617
[11]	RAMAKRISHNAN M, ZHOU X P, DYDAK U, et al. Gastric emptying of new-world milk containing A1 and A2 β-casein is more rapid as compared to milk containing only A2 β-casein in lactose maldigesters:A randomized, cross-over trial using magnetic resonance imaging[J]. Nutrients,2023,15(4):801. doi: 10.3390/nu15040801
[12]	DANILOSKI D, HAILU Y, BRODKORB A, et al. Impact of β-casein phenotype on the physical properties of skim milk powders and their subsequent digestion characteristics[J]. Food Hydrocolloids,2024,152:109918. doi: 10.1016/j.foodhyd.2024.109918
[13]	MENG Y, ZHOU Y B, LI H T, et al. Effectiveness of growing-up milk containing only A2 β-casein on digestive comfort in toddlers:A randomized controlled trial in China[J]. Nutrients,2023,15(6):1313. doi: 10.3390/nu15061313
[14]	张园园. β酪啡肽-7功能评价及A2 β酪蛋白基因型奶牛鉴定[D]. 扬州:扬州大学, 2023. [ZHANG Y Y. Function evaluative of β casomorphim-7 and identification of A2 β-casein genotype cows[D]. Yangzhou:Yangzhou University, 2023.] ZHANG Y Y. Function evaluative of β casomorphim-7 and identification of A2 β-casein genotype cows[D]. Yangzhou: Yangzhou University, 2023.
[15]	刘纳. 酪蛋白组分分离、纯化研究[D]. 成都:西华大学, 2011. [LIU N. Studies on fractionation and purification of casein individuals[D]. Chengdu:Xihua University, 2011.] LIU N. Studies on fractionation and purification of casein individuals[D]. Chengdu: Xihua University, 2011.
[16]	鲁杏茹. A2型β-酪蛋白消化产物特性及免疫调节作用研究[D]. 哈尔滨:东北农业大学, 2023. [LU X R. Study on digestive product characteristics and immunomodulatory effects of A2 β-casein[D]. Harbin:Northeast Agricultural University, 2023.] LU X R. Study on digestive product characteristics and immunomodulatory effects of A2 β-casein[D]. Harbin: Northeast Agricultural University, 2023.
[17]	赵烜影. 水牛β-酪蛋白亚型结构表征及体外消化和抗氧化性能分析[D]. 哈尔滨:东北农业大学, 2019. [ZHAO H Y. Structure characterization, digestion in vitro and antioxidation of β-casein phenotypes in buffalo[D]. Harbin:Northeast Agricultural University, 2019.] ZHAO H Y. Structure characterization, digestion in vitro and antioxidation of β-casein phenotypes in buffalo[D]. Harbin: Northeast Agricultural University, 2019.
[18]	EGGER L, MENARD O, BAUMANN C, et al. Digestion of milk proteins:Comparing static and dynamic in vitro digestion systems with in vivo data[J]. Food Research International,2019,118:32−39. doi: 10.1016/j.foodres.2017.12.049
[19]	何思宇. 叶绿素—酪蛋白纳米分散体系的构建及初步评价[D]. 上海:上海交通大学, 2019. [HE S Y. Preparation and preliminary evaluation of chlorophylls-casein nanodispersion[D]. Shanghai:Shanghai Jiao Tong University, 2019.] HE S Y. Preparation and preliminary evaluation of chlorophylls-casein nanodispersion[D]. Shanghai: Shanghai Jiao Tong University, 2019.
[20]	田浩. 可溶性大豆多糖在酸性条件下稳定不同乳蛋白的影响因素研究[D]. 无锡:江南大学, 2021. [TIAN H. Factors influencing the stabilization of different milk proteins by soluble soybean polysaccharides under acidic conditions[D]. Wuxi:Jiangnan University, 2021.] TIAN H. Factors influencing the stabilization of different milk proteins by soluble soybean polysaccharides under acidic conditions[D]. Wuxi: Jiangnan University, 2021.
[21]	KULBABA R, SAKHATSKYI M, LIASHENKO Y. Comparative analysis of A1 and A2 allele detection efficiency for bovine CSN2 gene by AS-PCR methods[J]. Acta Biochimica Polonica,2023,70(1):205−209.
[22]	RAHIMI Z, GHOLAMI M, RAHIMI Z, et al. Evaluation of beta-casein locus for detection of A1 and A2 alleles frequency using allele specific PCR in native cattle of Kermanshah, Iran[J]. Biharean Biologist,2015,9(2):85−87.
[23]	何圣发, 龙彩云, 王娇, 等. 牛乳主要过敏原αS1-酪蛋白的纯化鉴定及其多克隆抗体的制备[J]. 食品工业科技,2022,43(15):106−114. [HE S F, LONG C Y, WANG J, et al. Purification, identification and polyclonal antibody development for cow’s milk major allergen αS1-casein[J]. Science and Technology of Food Industry,2022,43(15):106−114.] HE S F, LONG C Y, WANG J, et al. Purification, identification and polyclonal antibody development for cow’s milk major allergen αS1-casein[J]. Science and Technology of Food Industry, 2022, 43（15）: 106−114.
[24]	THEKKILAVEEDU S, KRISHNASWAMI V, MOHANAN D P, et al. Lactic acid-mediated isolation of alpha-, beta- and kappa-casein fractions by isoelectric precipitation coupled with cold extraction from defatted cow milk[J]. International Journal of Dairy Technology,2020,73(1):31−39. doi: 10.1111/1471-0307.12646
[25]	LI S S, HU Q, CHEN C, et al. Formation of bioactive peptides during simulated gastrointestinal digestion is affected by α s1-casein polymorphism in buffalo milk[J]. Food Chemistry,2020,313:126159. doi: 10.1016/j.foodchem.2020.126159
[26]	KERN L, FABRE O, SCHER J, et al. Chemical fractionation of caseins by differential precipitation:Influence of pH, calcium addition, protein concentration and temperature on the depletion in α-and β-caseins[J]. International Journal of Food Science & Technology,2020,55(2):542−552.
[27]	OKAWARA Y, HIRANO H, KIMURA A, et al. Phos-tag diagonal electrophoresis precisely detects the mobility change of phosphoproteins in Phos-tag SDS-PAGE[J]. Journal of Proteomics,2021,231:104005. doi: 10.1016/j.jprot.2020.104005
[28]	徐一宁, 曹传爱, 孔保华, 等. 不同形态的可得然凝胶对肌原纤维蛋白凝胶特性和体外消化特性的影响[J]. 食品工业科技,2024,45(16):73−84. [XU Y N, CAO C A, KONG B H, et al. Effects of incorporation of different forms of curdlan gels on the gelling properties and in vitro digestibility of myofibrillar protein gels[J]. Science and Technology of Food Industry,2024,45(16):73−84.] XU Y N, CAO C A, KONG B H, et al. Effects of incorporation of different forms of curdlan gels on the gelling properties and in vitro digestibility of myofibrillar protein gels[J]. Science and Technology of Food Industry, 2024, 45（16）: 73−84.
[29]	JIANG Y, LI S, YUAN R, et al. Preparation of casein hydrolysate by two-step enzymatic hydrolysis and its immunomodulatory activities in vitro and in vivo[J]. Food Bioscience,2024,59:104007. doi: 10.1016/j.fbio.2024.104007
[30]	VOROB’EV M M, ACIKGOZ B D, GULER G, et al. Proteolysis of micellar β-casein by trypsin:Secondary structure characterization and kinetic modeling at different enzyme concentrations[J]. International Journal of Molecular Sciences,2023,24(4):3874. doi: 10.3390/ijms24043874
[31]	REICHE A M, MARTIN-HERNANDEZ M C, NEFF A S, et al. The A1/A2 β-casein genotype of cows, but not their horn status, influences peptide generation during simulated digestion of milk[J]. Journal of Dairy Science,2024,107(9):6425−6436. doi: 10.3168/jds.2024-24403
[32]	TU M L, LIU H X, ZHANG R Y, et al. Analysis and evaluation of the inhibitory mechanism of a novel angiotensin-I-converting enzyme inhibitory peptide derived from casein hydrolysate[J]. Journal of Agricultural and Food Chemistry,2018,66(16):4139−4144. doi: 10.1021/acs.jafc.8b00732
[33]	MUDGIL P, ALMAZROUI M, REDHA A A, et al. Cow and camel milk-derived whey and casein protein hydrolysates demonstrated effective antifungal properties against selected candida species[J]. Journal of Dairy Science,2022,105(3):1878−1888. doi: 10.3168/jds.2021-20944
[34]	SONG Y, WANG Z C, JI H, et al. Fatty acid modification of casein bioactive peptides nano-assemblies, synthesis, characterization and anticarcinogenic effect[J]. International Journal of Biological Macromolecules,2024,254:127718. doi: 10.1016/j.ijbiomac.2023.127718