Hydrolysis of oligosaccharides in the gastrointestinal tract alters their prebiotic effects on probiotic strains

Abstract

Oligosaccharides have been widely used as prebiotics in the food industry, however their properties have been examined in vitro, without considering hydrolysis in the human digestive tract, especially in the small intestine. Here, we hypothesized that the prebiotic effects and utilization efficiency of ingested oligosaccharides would be altered in the colon, as their structures are partially hydrolyzed during digestion. Different types of oligosaccharides were partially degraded during simulated digestion, and digestible monosaccharides were released from the initial substrates. The growth of some probiotic strains responded to the presence of digestible/absorbable mono- and disaccharides (components of the prebiotic oligosaccharides), but not to that of the oligosaccharides themselves. These findings regarding oligosaccharide degradation in the gastrointestinal tract can be used to achieve greater experimental accuracy when examining the effects of prebiotics on gut flora via in vitro studies (e.g., on fecal fermentation or microbial growth rates).

Supplementary information: The online version contains supplementary material available at 10.1007/s10068-023-01474-z.

Keywords: Colon microbiota; Oligosaccharide; Prebiotic; Simulated digestive tract.

Fig. 1

Hydrolysis of galacto-, fructo-, isomalto-, and xylo-oligosaccharides (GOS, FOS, IMOS, and XOS, respectively) at different phases of simulated digestion. (A) Oral phase: hydrolysis by α-amylase from human saliva; (B) Gastric phase: exposure to acidic conditions (pH 2); and (C) Intestinal phase: degradation by porcine pancreatic α-amylase. Waxy corn starch (WCS) was used as the digestible control for the α-amylase reaction. Groups with different lowercase letters (a–c) are significant differences at p < 0.05

Fig. 2

Hydrolysis of galacto-, fructo-, isomalto-, and xylo-oligosaccharides (GOS, FOS, IMOS, and XOS; (A–D), respectively) by mammalian α-glucosidases (24 h at 37 °C). Gray and black lines: chromatograms for 0 and 24 h, respectively, of enzymatic digestion

Fig. 3

Prebiotic effects of the digestible/absorbable mono- and di-saccharides in galacto-, fructo-, isomalto-, and xylo-oligosaccharides (GOS, FOS, IMOS, and XOS; (A–D), respectively), quantified as bacterial growth relative to the control. ‘Blank’: medium without a carbon source. ‘Control’: medium with only digestible/absorbable mono- and di-saccharides. ‘Sample’: medium containing the oligosaccharide sample. (A–D): Groups with different lowercase letters (a–c) have significant differences at p < 0.05 between the blank, control, and sample