不同发酵剂对发酵驴乳酸奶在冷藏期间品质的影响

Effects of different starters on the quality of fermented donkey milk yogurt during cold storage

目的研究不同发酵剂对发酵驴乳酸奶在冷藏期间品质的影响。方法对3种发酵剂发酵的驴乳酸奶在冷藏期间微生物指标、理化指标和感官品质进行检测分析。结果用市售酸奶A发酵的驴乳酸奶LR-A在冷藏的1~26 d中乳酸菌活菌数由69.33×10^(7)CFU/mL下降至0.50×10^(7)CFU/mL,用市售酸奶B发酵的驴乳酸奶LR-B冷藏前7 d乳酸菌活菌数显著下降(P<0.05),7 d后又逐渐上升,而用传统酸奶C发酵的驴乳酸奶LR-C在冷藏过程中乳酸菌活菌数一直呈上升趋势;3种发酵剂发酵的驴乳酸奶在冷藏第14d时细菌菌落总数均达到最高值,持水力在冷藏前14 d均呈现下降趋势,总体口感较佳,LR-C冷藏第7~26 d的持水力均高于LR-A和LR-B;随冷藏时间的延长,pH整体呈下降趋势(LR-B>LR-A>LR-C),总酸度值的变化趋势与pH相反(LR-C>LR-A>LR-B)。结论不同发酵剂对发酵驴乳酸奶在冷藏期间品质影响差异较大,LR-A和LR-B在冷藏至26 d时仍可饮用,LR-C在冷藏14 d后因酸度太高,超出可接受范围。

Objective To study the effects of different starters on the quality of fermented donkey milk yogurt during cold storage.Methods The microbial index,physical and chemical index and sensory qualities of donkey milk yogurt fermented by 3 kinds of starter during cold storage were detected.Results The number of viable lactic acid bacteria in donkey milk yogurt LR-A fermented with market yogurt A decreased from 69.33×10^(7)CFU/mL to 0.50×10^(7)CFU/mL during 1-26 days of cold storage,and the number of viable lactic acid bacteria in LR-B donkey milk yogurt fermented with market yogurt B decreased significantly on the first 7 days before cold storage(P<0.05),and after 7 days,it gradually increased.However,the number of viable lactic acid bacteria in donkey milk yogurt LR-C fermented with traditional yogurt C showed an upward trend during cold storage.The total number of bacterial colonies of donkey milk yogurt fermented by 3 kinds of starter cultures reached the highest value on the 14th day of cold storage,and the water-holding capacity showed a decreasing trend on the first 14 days of cold storage,and the overall taste was better,and the water-holding capacity of LR-C was higher than that of LR-A and LR-B during 7-26 days of cold storage,and the pH of the whole decreased with the extension of cold storage time(LR-B>LR-A>LR-C),and the change trend of total acidity value was opposite that of pH(LR-C>LR-A>LR-B).Conclusion The effects of different starters on the quality of fermented donkey milk yogurt during cold storage are quite different,LR-A and LR-B are still drinkable after 26 days of cold storage,but LR-C is too acidic after 14 days of cold storage,which exceeded the acceptable range.