Yields of three acids during simulated fermentation of inulin and xylo-oligosaccharides enhanced by six exogenous strains

Abstract

Three acids (acetic, propionic and butyric acids) yielded from simulated colonic fermentation of inulin and xylo-oligosaccharides (XOS) in the absence and presence of six exogenous strains were investigated in this study. Both inulin and XOS were fermented by fecal extract (FE) prepared from healthy adults and by an exogenous strain for 48 h, and three acids generated in fermentation products at five time periods were detected by gas chromatography. Inulin and XOS during fermentation were capable of producing more propionic and butyric acids, respectively, whilst inoculation using one strain culture into fermentation systems mostly increased yields of three acids. In inulin-containing fermentation systems, these strains increased yields of propionic and butyric acids by 6–34 and 206–250%, respectively. In XOS-containing fermentation systems, these strains did not enhance yield of propionic acid, but increased yield of butyric acid by 50–96%. In general, Lactobacillus brevis, Lactobacillus plantarum, Lactobacillus rhamnosus, Enterococcus faecalis and Enterococcus faecium were more efficient than Lactobacillus acidophilus to increase yields of propionic and butyric acids. It is thus concluded that the six strains in total displayed beneficial effects on simulated fermentation of inulin and XOS through enhancing yields of three acids especially propionic and butyric acids with healthcare functions.