长保质期发酵乳低聚肽的特征分析

Characteristics of Oligopypeptide in Pasteurized Yoghurt with Long Shelf Life

以长保质期发酵乳为研究对象,分析对比了发酵前后和二次巴氏灭菌后的发酵乳中营养成分、低聚肽、游离氨基酸等各项指标的变化。分析对比了样品在常温条件下保存120 d内营养成分的变化和低聚肽分子质量分布特征,结果显示,发酵后样品中低聚肽及游离氨基酸含量显著增加,在经过二次灭菌及在保存期间内,140~1000 u和1000~2000 u的低聚肽及游离氨基酸的含量无明显变化,大于10000 u分子质量的肽类在保存期内部分降解,而其他分子质量范围的多肽含量在保存期间逐渐增加。二次巴氏灭菌处理后发酵乳中营养成分仅乳糖含量明显下降,其他各项理化指标在保存期内无显著变化,说明二次巴氏灭菌对发酵乳的营养成分并无明显影响。研究结果可为长保质期发酵乳的开发提供依据。

The pasteurized yoghurt with long shelf life was used as the research object,the nutritional changes,oligopeptide content,and composition of essential amino acids contained in oligopeptide before and after fermentation and after secondary pasteurized sterilization were analyzed.The changes of the nutrients in 120 d and the distribution of oligopeptides were compared at room temperature.The results showed that the content of oligopeptide and free amino acid in fermentation samples increased significantly,the oligopypeptide and free amino acid contents of 140~1000 u and 1000~2000 u showed no significant change,peptides greater than 10000 u were partially degraded during the storage period,while the polypeptide content in the other molecular mass range gradually increased during storage.After the treatment of secondary pasteurization,only the lactose content decreased significantly,and the other physical and chemical indicators did not change significantly during the preservation period,indicating that secondary pasteurized sterilization had no significant impact on the nutrition of pasteurized yoghurt.The results provide the basis for the development of long-shelf life pasteurized yoghurt.