In-vitro microbial production of conjugated linoleic acid by probiotic L. plantarum strains: Utilization as a functional starter culture in sucuk fermentation

Twenty-three probiotic Lactobacillus plantarum strains were screened in-vitro to determine their ability to produce conjugated linoleic acid (CIA). L. plantarum AA1-2 and L plantarum AB20-961 were identified as potential strains for CIA production. Optimum conditions for these strains to produce high levels of CIA were determined by evaluating the amount of added hydrolyzed sunflower oil (HSO) and initial pH levels in a nutrient medium. The highest CLA production was obtained in medium with pH 6.0 and 2% HSO (P < 0.05). Those strains were then used as starter culture in sucuk fermentation. Five sucuk treatments included a control (no starter culture), two sucuk groups with L. plantarum AA1-2 at the initial pH of 5.8 or 6.0 and two sucuk groups with L plantarum AB20-961 at the initial pH of 5.8 or 6.0. Results indicate that L. plantarum AB20-961 produced higher amount of CIA in sucuk at initial pH of 5.8 and 6.0 levels during first 24 h of fermentation compared with other groups. CIA isomer concentration decreased in all sucuk groups during the rest of the fermentation period (P < 0.05) and remained quite stable during the storage. This study demonstrated that probiotic L. plantarum AB20-961 can be used in sucuk manufacturing without posing any quality problems. (C) 2015 Elsevier Ltd. All rights reserved.