Six lactic acid bacterial （LAB） strains were isolated from traditionally fermented Xinjiang cheese and evaluated for functional and probiotic properties and potentials as starter cultures. The isolated six LAB strai...Six lactic acid bacterial （LAB） strains were isolated from traditionally fermented Xinjiang cheese and evaluated for functional and probiotic properties and potentials as starter cultures. The isolated six LAB strains com- prised Lactobacillus rhamnosus （one strain）, Lactobacillus helveticus （one strain）, and Enterococcus hirae （four strains）. All of the six strains were tolerant to acidic and bile salt conditions. Among which, the L. rhamnosus R4 strain showed more desirable antimicrobial, auto-aggregation, and hydrophobic activity. In addition, the strain L. rhamnosus R4 exhibited the highest level of free radical scavenging activity （53.78% of 1,1-dipheny1-2-picrylhydrazyl （DPPH） free radicals and 45.79% of hydroxyl radicals）. L. rhamnosus R4 also demonstrated cholesterol and triglyceride degrada- tion by 50.97% and 28.92%, respectively. To further examine the health-promoting effects of these LAB strains on host lifespan, Caenorhabditis elegans was used as an in vivo model. Worms fed LAB as a food source had significant differences in lifespan compared to those fed Escherichia coil OP50 （as a negative control）. Feeding of L. rhamnosus R4 extended the mean lifespan of C. elegans by up to 36.1% compared to that of the control. The results suggest that the strains isolated from Xinjiang fermented dairy products have high potential as starter cultures in the cheese industry.展开更多
基金supported by the National Key Technology R&D Program of China(No.2012BAD33B08)the Zhejiang Provincial Natural Science Foundation of China(No.LY12B06006)+1 种基金the Research Program of Education Department of Zhejiang Province(No.Y201122061)the National Natural Science Foundation of China(No.20906060)
文摘Six lactic acid bacterial （LAB） strains were isolated from traditionally fermented Xinjiang cheese and evaluated for functional and probiotic properties and potentials as starter cultures. The isolated six LAB strains com- prised Lactobacillus rhamnosus （one strain）, Lactobacillus helveticus （one strain）, and Enterococcus hirae （four strains）. All of the six strains were tolerant to acidic and bile salt conditions. Among which, the L. rhamnosus R4 strain showed more desirable antimicrobial, auto-aggregation, and hydrophobic activity. In addition, the strain L. rhamnosus R4 exhibited the highest level of free radical scavenging activity （53.78% of 1,1-dipheny1-2-picrylhydrazyl （DPPH） free radicals and 45.79% of hydroxyl radicals）. L. rhamnosus R4 also demonstrated cholesterol and triglyceride degrada- tion by 50.97% and 28.92%, respectively. To further examine the health-promoting effects of these LAB strains on host lifespan, Caenorhabditis elegans was used as an in vivo model. Worms fed LAB as a food source had significant differences in lifespan compared to those fed Escherichia coil OP50 （as a negative control）. Feeding of L. rhamnosus R4 extended the mean lifespan of C. elegans by up to 36.1% compared to that of the control. The results suggest that the strains isolated from Xinjiang fermented dairy products have high potential as starter cultures in the cheese industry.
