引起酸奶制品发生后酸化的主要发酵剂菌及性质

The main starter bacteria to Induce the postacidification of yogurt

将培养物中保加利亚乳杆菌与嗜热链球菌调节为相同 pH值 (4 50 )、起始相同菌数7 4× 1 0 7个 /ml后分别贮存 (2 5℃ ) ,在贮存第 1 1天嗜热链球菌的 pH值为 4 57,保加利亚乳杆菌的为 3 85。将保加利亚乳杆菌确定为导致后酸化发生的主要发酵剂菌 ,是其细胞壁或细胞膜的性质保护了乳糖酶活性。

S.t and L.b were incubated respectively in the storage temperature 25 ℃.The cultures of S.t and L.b were in the same condition(the count of bacteria were 7 4×10 7 cfu/ml pH was 4 50).At the 11 day of storage,the culture pH value of S.t was 4.57,otherwise,L.b was 3.85.S.t was confirmed mainly to occur postacidification.S.t′s cell wall or cell membrane protected the activity of β-galactosidase.