Possibility of a Product of Awamori Moromi Vinegar Fermented by <i>Lactobacillus plantarum</i> K-3 as a Prebiotic

Abstract

Awamori moromi vinegar (AMV) contains essential amino acids and citric acid; however, its peculiar flavor prevents its acceptance as a functional food material. In a previous study, a fermented product of AMV (FP-AMV) was prepared using <i>Lactobacillus</i> <i>plantarum</i> K-3 to resolve the peculiar flavor of AMV, and its possibility to improve lipid metabolism through an approach to gut microbiota was suggested. In this study, using <i>in vitro</i> and <i>in vivo</i> experiments, it was aimed to determine whether FP-AMV could be used as a prebiotic to improve gut microbiota. The <i>in vitro</i> prebiotic assay showed increased turbidity for eight lactic acid bacteria and five bifidobacteria with the addition of FP-AMV, suggesting the comprehensive bacterial growth-promoting effect of FP-AMV. In contrast, the growth of <i>Clostridium</i> perfringens was greatly suppressed by FP-AMV. Therefore, an animal experiment was conducted to investigate the relationship between FP-AMV ingestion and the gut microbiota. Gut microbiota analysis of fecal samples in animal experiments proved that FP-AMV induced not only an increase in the prevalence of probiotic species, such as <i>Lactobacillus</i> and <i>Bacteroides</i>, but also a decrease in the prevalence of pathogenic species, such as <i>Clostridium</i>, in the gut microbiota of male C57BL/6JJcl mice. These results suggest that FP-AMV contributes to the improvement of the gut microbiota and the gut environment. Thus, it can be used as a potential prebiotic food.