CLA-Producing Probiotics for the Development of a Yogurt-Type Beverage

This study examined the ability of four beneficial strains (Lactobacillus rhamnosus LbRE-LSAS, Bifidobacterium animalis subsp. lactis Bb12, and two yogurt starters TA040 and LB340) to ferment MRS or milk containing free linoleic acid (0, 0.5, or 1 mg/mL). The goal was to produce an enriched conjugated linoleic acid (CLA) isomers’ yogurt-type beverage. Linoleic acid (LA) at 0.5 mg/mL did not interfere with the growth of the assayed bacteria on de Man Rogosa and Sharpe broth (MRS) or milk. On the other hand, increasing the content of LA in the MRS or yogurt-type beverage to 1 mg/mL slightly inhibited all strains and prevented accumulating high biomasses. A gas chromatography analysis of the fatty acid profiles confirmed the bioconversion of LA. The yogurt starters TA040 and LB340 had the highest bioconversion rates in the yogurt-type beverages, whereas the probiotic Bb12 strain was the most interesting at converting LA into its active CLA. CLA from the MRS supernatants of TA040, Bb12, and LbRE-LSAS had maximum antibacterial activities against S. typhimurium, E. coli, and S. aureus, respectively. Whey from the Bb12 beverage showed an inhibitory effect against all pathogens. These results suggest that all strains could be used as starter cultures in the proposition of a yogurt-type beverage with a high CLA content and antibacterial potential.