In vitro digestion and fermentation of released exopolysaccharides (r-EPS) from Lactobacillus delbrueckii ssp. bulgaricus SRFM-1

Abstract

The aim of this study was to investigate the in vitro digestion and fermentation prebiotic properties of three released-exopolysaccharide fractions (r-EPS1, r-EPS2 and r-EPS3) from Lactobacillus delbrueckii ssp. bulgaricus SRFM-1. There were no free oligosaccharides and/or monosaccharides for r-EPS1 before and after simulated buccal, gastric and small intestinal (GSI) digestion in vitro. In contrast, r-EPS2 (13.4 %) and r-EPS3 (10.6 %) generated a few monosaccharides after digestion. Additionally, r-EPS1 and r-EPS2 seemed to present a strong bifidogenic effect comparing to inulin, as they exhibited high values of selectivity index (13.17 and 12.84, respectively). Furthermore, the fermentation with r-EPS1 produced the highest contents of acetic acid and lactic acid (56.3 mM and 44.29 mM, respectively), which resulted in the highest amounts of total short chain fatty acid (145.51 mM) followed by r-EPS2 (135.57 mM) and inulin (99.28 mM). These results indicated that r-EPS from L. delbrueckii ssp. bulgaricus SRFM-1 could be a good potential candidate for new functional food prebiotic.

Keywords: In vitro digestion; In vitro fermentation; Lactobacillus delbrueckii ssp. bulgaricus SRFM-1; Released exopolysaccharide (r-EPS); Selectivity index (SI); Short chain fatty acid (SCFA).