新疆酸马奶中嗜酸乳杆菌的发酵特性研究

Study on the Fermentable Properties of Lb. acidophilus Isolated from Traditional Koumiss of Xinjiang

【目的】从新疆传统酸马奶以及市售酸奶中分离鉴定出嗜酸乳杆菌,从中筛选出具有潜在益生特性的菌株进行发酵特性研究,寻找具有优良发酵特性的嗜酸乳杆菌菌株。【方法】利用MRS培养基活化嗜酸乳杆菌,并采用平板菌落计数法测定发酵乳中嗜酸乳杆菌的活菌数,同时利用pH计和NaOH标准溶液滴定酸度以测定发酵乳在发酵过程以及冷藏期间的酸度变化。【结果】发酵24 h,嗜酸乳杆菌G14、S22和G13先后到达发酵终点的顺序依次为G14>S22>G13,其中嗜酸乳杆菌G14的产酸能力最强,发酵乳的滴定酸度为94.83°T,pH值为4.30。4℃冷藏期间,嗜酸乳杆菌G14和S22发酵乳的后酸化程度较菌株G13低。冷藏16d时,各菌株仍具有较高的对数存活率,且菌株G13、S22和G14的对数存活率分别为79.18%、80.12%和85.57%,存活能力的顺序依次为G14>S22>G13。【结论】嗜酸乳杆菌G14产酸能力最强,最先到达发酵终点。冷藏过程中,嗜酸乳杆菌G14和S22的发酵乳后酸化程度较低,且嗜酸乳杆菌G14的对数存活率最高。

[ Objective ] Some fermentable properties of the three strains of Lb. acidophilus isolated from the collected samples of traditional koumiss in Xinjiang and the yogurt sold in the city were studied in order to find the excellent fermentation characteristics of lactobacillus acidophilus bacteria. [ Method] Lb. aeidophilus was activated by the MRS medium and live bacteria number of Lb. lactobaeillus in the yogurt was determined with the flat colonies test. Meanwhile pH plan and NaOH standard were used to titrate solution acidity of the yogurt during the fermentation process and the cold storage. [ Result] After fermentation 24 h, Lb. acidophi- lus of G14, S22 and G13 arrive at the end of the fermentation, the sequence of which is G14 〉 S22 〉 G13. Lb. acidophilus of G14 has a higher ability of acidity production. In the 24 hours, the acidity of yogurt was 94.83 °T, and the pH was 4.30. During the fermentation at 4℃, lactobacillus acidophilus of yoghurt G14 and S22 after acidification was lower than that of the G13. On the 16 days of refrigeration, all the strains still have high logarithmic survival ability. The logarithmic survival rate of G13, S22 and G14 are 79.18% , 80. 12% and 85.57%, respectively. Their sequence is G14 〉 S22 〉 G13. [ Conclusion] The test of G14 had a higher ability of acidity production, being the first one to reach the end of fermentation. During the refrigera- tion, post acidification of lactobaeillus acidophilus of yoghurt G14 and S22 arrive at the low level and G14 has a higher ability of livability.