Modulation of gut microbiota and their metabolites by functional mulberry juice non-thermally pasteurized using microfiltration

Background: Mulberry fruit is a source of phenolic compounds and has biological properties. This study aimed to assess the effects of isomaltooligosaccharide (IMO) added to mulberry juice on prebiotic activity and gut fermentation properties.Objectives: The study aimed to produce mulberry juice supplemented with IMO, which might generate short chain fatty acids (SCFA), and to examine the effects of a prebiotic activity after fecal fermentation.Materials and methods: Functional mulberry juices were prepared with three different levels of isomaltooligosaccharide (IMO), namely 0% (MBI0), 2% (MBI2), and 8% (MBI8). The study tested mulberry juices supplemented with IMO, which generated short-chain fatty acids (SCFA), phenolic metabolites, and favored beneficial gut bacteria, and examined the prebiotic activity after fecal fermentation by the colonic microbiota. A crossflow hollow fiber microfiltration system with a 0.22 μm pore size was employed to deliver permeates considered non-thermally pasteurized juices.Results: The results show that short chain fatty acids (SCFA) included large propionic acid and butyric acid concentrations at 48h. The percent of bifidobacteria significantly increased to 5.03% and 17.53% in 24 hours fermentation of MBI2 and MBI8, respectively. After fecal batch culture fermentation, some anthocyanin metabolites such as 3-(2-hydroxyphenyl) propionic acid, 3,4-dihydroxybenzaldehyde, L-phenylalanine, and aminocaproic acid, were detected. Therefore, IMO can serve as a potential prebiotic ingredient added in mulberry juice for promoting the growth of beneficial gut microbiota.Conclusion: The results show that IMO favored beneficial microorganisms in the gut and contributed to biologically active compounds such as metabolites of polyphenols and anthocyanins in the gut.Keywords: Mulberry, isomaltooligosaccharide, prebiotic, gut microbiota, metabolites