酸乳低温储存期间乳蛋白和游离氨基酸变化及质构关系

Study on variations of yoghurt milk proteins and free amino acids,and relationship between texture during low-temperature storage

通过对酸乳低温存储期间(4℃,28d)乳蛋白及其降解产物与质构(硬度、稠度、黏度、黏聚性)变化的研究,探讨乳蛋白、多肽、游离氨基酸与质构的相关性,并比较了保加利亚乳杆菌与嗜热链球菌(1∶1)混合发酵剂和嗜热链球菌单独发酵剂的影响。结果表明,酸乳低温储存6～10d前质构急剧增加,储存6～10d后质构趋于稳定,两种酸乳的多肽、游离氨基酸及质构在储存期间呈增长趋势,且乳蛋白、多肽、游离氨基酸含量与酸乳稠度和硬度的相关性要高于黏度和粘聚性。

The changes of yoghurt texture （firmness, consistency, firmness, cohesiveness）, milk protein and degradation products were studied during low-temperature storage in this paper, the correlation between milk proteins, polypeptides, free amino acids and texture were studied, and compared the effects between mixed starter culture （LactobadUus bulgaricus： Streptococcus Thermophilus=1：1） and single starter culture （Streptococcus Thermophilus）. The result showed that the texture of yoghurt increased sharply before 6-10 d and tended to be stable after 6-10 low-temperature storage, the content of polypeptides and free amino acids had a increasing trend in two yoghurts, the correlation between milk proteins, polypeptides, free amino acids and consistency, firmness was higher than that of viscosity and cohesiveness.