本试验以耐酸、耐氧、定植力强及功能性丰富的鼠李糖乳杆菌GG(Lactobacillus rhamnosus GG,L-GG)单菌发酵的驼乳和牛乳为研究对象,通过鼠李糖乳杆菌GG的生长曲线确定发酵时间,评价不同发酵时间和不同储藏时间下,发酵驼乳与牛乳的发酵特性(pH、滴定酸度和活菌数)、蛋白质水解活性和降糖活性(α-淀粉酶和α-葡萄糖苷酶抑制活性)。结果表明,pH、滴定酸度、活菌数和蛋白质水解活性存在一定的内在联系。随着发酵时间的增加,两种发酵乳的pH下降,滴定酸度上升,活菌数和蛋白质水解活性也在不断增加。在储藏期间,pH、滴定酸度、活菌数和蛋白质水解活性逐渐趋于稳定。发酵驼乳较发酵牛乳的pH低,滴定酸度、活菌数和蛋白质水解活性高,在维持发酵品质和延长货架期方面优于发酵牛乳。经过发酵后的原料乳降糖活性提高,在发酵和储藏期间发酵驼乳和牛乳都表现出很高的α-淀粉酶抑制活性,在储藏期间表现出较高的α-葡萄糖苷酶抑制活性,整体上看发酵驼乳的降糖活性优于发酵牛乳。
Single bacteria Lactobacillus rhamnosus GG(L-GG)with strong acid,oxygen resistance,engraftment and rich function fermented camel milk and cow milk. The fermentation time was determined by growth curve of Lactobacillus rhamnosus GG,and the fermentation characteristics(pH,titratable acidity and bacterial counts),the proteolytic activity and hypoglycemic activity(α-amylase and α-glycosidase inhibition activity)of camel milk and cow milk under different fermentation time and storage time were evaluated. The results showed that pH,titratable acidity,bacterial counts and proteolytic activity were interrelated. With the increasing of fermentation time,the pH of the two fermented milk decreased,while the titratable acidity,bacterial counts and proteolytic activity increased. During the storage period,pH,titratable acidity,bacterial counts and proteolytic activity tended to be stable. The pH of fermented camel milk was lower than that of fermented cow milk,and the titratable acidity,bacterial counts and proteolytic activity were higher. It was superior to fermented cow milk in maintaining fermentation quality and extending shelf life. After fermentation,the hypoglycemic activity of raw milk was improved. During fermentation and storage,both camel milk and cow milk showed high α-amylase inhibitory activity,and higher α-glucosidase inhibitory activity during storage. Overall the hypoglycemic activity of fermented camel milk was better than that of fermented cow milk.
Science and Technology of Food Industry
Lactobacillus rhamnosus GG(L-GG)