Lactobacillus paracasei ZFM54 alters the metabolomic profiles of yogurt and the co-fermented yogurt improves the gut microecology of human adults
Description
At present, lactobacillus have been used to make various oral dietary supplements and drugs marketed as a potential way to prevent numerous gastrointestinal diseases. Among them, yogurt has been confirmed to offer a positive impact on human health. The study concentrated on the impacts of Lactobacillus paracasei ZFM54 on the volatile and non-volatile metabolomic profiles of yogurt and the effects of the resulted yogurt on the gut microecology of adults. We firstly optimized the fermentation conditions using single factor assay and response surface test. Under the optimized condition, we obtained yogurt LS (Lactobacillus paracasei ZFM54 and Commercial starter VEGE 033 co-fermented yogurt) and yogurt S (Commercial starter VEGE 033 fermented yogurt). Then we employed SPME-GC-MS to compare the volatile metabolites of yogurt LS and S, and used the untargeted UPLC-Q-TOF-MS platform to analyze the non-volatile metabolites of yogurt LS and S. Finally, the regulatory effects of the co-fermented yogurt on intestinal microecology of volunteers were investigated by 16S rDNA sequencing and short-chain fatty acids (SCFAs) analysis after a 2-week continuous consumption of different yogurts. The results showed that the optimal fermentation conditions of L. paracasei ZFM54 compound yogurt: strain ratio, 2:1; inoculation amount, 1.5%; fermentation time, 8 hours; fermentation temperature, 42 ℃; sucrose content, 6.5%. Through SPME-GC-MS and UPLC-Q-TOF-MS, we confirmed that L. paracasei ZFM54 could significantly influence volatile and nonvolatile metabolomic profiles of yogurt to improve many volatile acid contents and alter lots of nonvolatile metabolites, resulting in better flavor and quality. Through comparing the effects of yogurt LS and S on the gut microbiota of the volunteers, as well as on the contents of SCFAs in the feces of the volunteers, we found that ZFM54 optimized the flora structure and promoted the production of acetic acid, propionic acid and butyric acid. This work provides theoretical basis and experimental evidence for the commercial application of L. paracasei ZFM54 in improving the quality of yogurt and coordinating intestinal microecology.