【摘要】 研究了不同来源的7株保加利亚乳杆菌在乳中的生长与发酵特性、后酸化活性以及抗冷冻干燥特性。结果表明,7菌株在乳中42℃发酵,L.b-S1和L.b-DR凝乳时间最短,为3 h,凝乳后的活菌数、pH值、滴定酸度均无显著差别,活菌数均达1×108 mL-1以上,pH值均达4.5～5.0,滴定酸度均达90～100°T;7菌株在发酵后的酸乳中冷藏期间,L.b-S1和L.b-DR的后酸化活性最低,4℃冷藏21 d,酸度上浮不足10°T,pH值下降0.2～0.4,活菌数下降1个log数量级左右;7菌株在以脱脂乳为保护剂的冷冻干燥试验中,L.b-S1抗冻干性最强,其次为L.b-DR,其冻干存活率分别达31.46%和20.39%。更多还原

【Abstract】 In this paper,the character of fermentation,resistant of freeze-drying and postacidification of different strains of Lactobacillus bulgaricus was studied.The result showed that the coagulation time of L.b-DR and L.b-S1 was 3 h,which was shorter than others and the living cell number of which was more 1×108 cfu/mL,pH was 4.5～5.0 and the titration acidity was 90～100 °T.During the cold storage of the yoghourt at 4 ℃,the postacidification of L.b-DR and L.b-S1 was inapparent and a increase in acidity was less than 10 °T,a decrease in pH was 0.2～0.4 and a decrease in living cell number didn’t amount to one log rank.Lyophilization experiments showed that the resistance of freeze-dry of L.b-S1 was the best in the seven lactobacilluses and L.b-DR was the second.The freeze-dry livability of L.b-S1 was 31.46% and L.b-DR’s was 20.39%.更多还原