为探究羊乳酪蛋白亚组分及其配比调控对婴幼儿消化性的影响,该研究以山羊乳胶束态酪蛋白为原料,采用选择性沉淀技术分离制备κ-酪蛋白富集物、β-酪蛋白富集物和αs-酪蛋白富集物,并按母乳酪蛋白亚组分配比进行复配。通过婴幼儿体外模拟胃肠消化,以山羊乳全酪蛋白为对照,比较5种酪蛋白样品的胃凝块、蛋白残留率、游离氨基含量和多肽分子质量分布等关键指标。结果表明,κ-酪蛋白富集和β-酪蛋白富集物在胃消化过程中均形成小而松散的凝块,有利于蛋白的降解并产生更多的游离氨基和小分子肽段,而αs-酪蛋白富集物的胃凝块大且致密,蛋白残留率和蛋白水解度显著较低。与全酪蛋白相比,复配酪蛋白在胃消化过程中形成的凝块颗粒尺寸小,结构松散,蛋白残留率低、水解程度高,产生较多的小分子肽段;肠消化过程中蛋白水解产生的游离氨基、小分子肽段占比显著增加。综上所述,κ-酪蛋白富集物和β-酪蛋白富集物的消化性优于αs-酪蛋白富集物,按照母乳酪蛋白亚组分配比调控的复配酪蛋白的消化性优于全酪蛋白。该研究为羊乳基婴儿配方奶粉的开发提供参考依据。
To investigate the effects of caprine milk casein subfractions and the ratio adjustment on the digestibility of infants, in this study, κ-casein enrichment, β-casein enrichment, and αs-casein enrichment were fractionated by selective precipitation using caprine micellar casein concentrate as raw material and then compounded according to the ratio of breast milk casein subfractions.In vitro simulated gastrointestinal digestion of infants and caprine milk whole casein was used as a control.Key indicators such as gastric clot, protein residue rate, free amino group content, and polypeptide molecular weight distribution of the different casein samples were compared among five casein samples.Results showed that both κ-casein enrichment and β-casein enrichment formed small and loose clots during gastric digestion, which was conducive to protein degradation and the production of more free amino groups and small molecular peptides.However, the gastric clots of αs-casein enrichment were large and dense, and the protein residual rate and degree of hydrolysis were significantly lower.Compared with whole casein, compound casein had smaller particle size, looser structure, lower protein residue rate, higher degree of hydrolysis, and produced more small molecular peptides.The amount of free amino and small molecular peptides produced by proteolysis increased significantly during intestinal digestion.In conclusion, the digestibility of κ-casein and β-casein enrichment was better than that of αs-casein enrichment, and the compound casein adjusted according to the ratio of breast milk casein subfractions was better than that of whole casein.This study provides a reference for the development of caprine milk-based infant formula.
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