Abstract

Kefir is fermented from lactic acid bacteria (LAB), yeasts and some other groups. It’s is considered as a natural probiotic products. However, there is no clear evidence that proves the probiotic activity of traditional products In this study, we demonstrated its probiotic activity and made an effort to increase the probiotic activity by adding Lactobacillus casei VTCC186 into passionfruit-Kefir. The density of LAB and yeast density increased 1,99 and 2,01 lg(cfu/mL) respectively compared with traditional passionfruitKefir.In addition, we also examined the gastric and bile salt tolerance of products’ microbial flora. Gastric survival rate of traditional Kefir is 39,36% and enrichedprobiotic Kefir is 52,01% after 2 hours. Moreover, products had strong antimicrobial activity and reduced cholesterol.