Abstract
In our previous study, short-chain inulin and inulin neoseries oligosaccharides (SCIINOs) were produced and purified from red onion juice. This study aimed to investigate the effect of SCIINOs on changes in the bacterial composition of fecal microbiota obtained from normal weight, overweight, and obese subjects using in vitro batch fermentation. Fermentation characteristics, including changes in fecal microbiota determined by the V3–V4 region of 16S rRNA amplicon sequencing, residual SCIINO content, and the resulting organic acid profiles, were determined. The results indicate that SCIINOs were fermentable, which occurred along with a decrease in the SCIINO content and an increase in lactic, acetic, propionic, and butyric acids. The microbial composition of fecal inoculum influenced the degree of SCIINO fermentation, which was then associated with the fermentation outcomes. Alpha-diversity results revealed that fermentation with and without SCIINOs decreased species richness, evenness, and diversity. Beta-diversity results revealed that fermentation of SCIINOs using all fecal inocula negatively affected the abundance of Escherichia-Shigella and Klebsiella while positively affecting the abundance of Lactococcus. The enrichment of Lactococcus was confirmed by an independent study, indicating that two reference strains of Lactococcus lactis efficiently utilized neokestose and nystose as the major FOS constituent present in SCIINOs.