西藏牧区自然发酵牦牛酸奶的乳酸菌菌种筛选及工艺优化

采用从西藏、川西青藏高原牧区自然发酵牦牛酸奶中筛选出的发酵性能优良的4株乳酸菌(LP1、LP2、LP3、LP4)进行组合发酵试验,经过纸片法筛选出优势发酵组合,以及其发酵牦牛酸奶的凝乳时间、滴定酸度、感官评价可以得出(LP1和LP2)组合为本试验的最佳发酵菌种组合。因此选用此菌种组合发酵牦牛酸奶,经过L16(44)正交试验得出牦牛酸奶发酵的最佳工艺条件为:发酵温度42℃、接种量6%、加糖量4 g/100 m L、菌种LP1与LP2浓度比为2∶1,此条件下发酵的牦牛酸奶凝固均匀,组织结构光滑细腻,无乳清析出,具有浓郁的酸奶风味。

Screening of Dominant Lactic Acid Bacteria from Naturally Fermented Yak Milk in Tibetan Pastoral Areas and Optimization of Fermentation Conditions for Yak Yogurt Production

Four Lactobacillus strains (LP1, LP2, LP3, and LP4) with excellent fermentation performance isolated from
homemade yak yogurt samples collected in Tibetan plateau pastoral areas were used in combination to ferment yak yogurt.
Using the disc diffusion method, the combination of LP1 and LP2 was screened as the best culture starter for the production
of yak yogurt in terms of coagulation time, titratable acidity and sensory evaluation. The optimum fermentation parameters
for yak yogurt were obtained through an orthogonal array design L16 (44) as follows: fermentation temperature, 42 ℃;
inoculum amount, 6%; sugar concentration, 4 g/100 mL; and LP1 to LP2 ratio, 2:1. Under these conditions, the fermented
yak milk revealed even solidification, delicate and smooth texture, no whey separation and rich yogurt flavor.