BACKGROUND: Grape seed extract (GSE) phenolics have potential health-promoting properties, either from compounds present within the extract, or metabolites resulting from gastrointestinal tract (GIT) fermentation of these compounds. This study describes how GSE affected the kinetics and end-products of starch fermentation in vitro using pig intestinal and fecal inocula. Six GSE concentrations (0, 60, 125, 250, 500, and 750 µg ml−1 were fermented in vitro by porcine ileal and fecal microbiota using starch as the energy source. Cumulative gas production, and end-point short chain fatty acids and ammonia were measured.
RESULTS: GSE phenolics altered the pattern (gas kinetics, and end-products such as SCFA and NH) of starch fermentation by both inocula, at concentrations above 250 µg ml−1. Below this level, neither inoculum showed any significant (P > 0.05) effect of the GSE.
CONCLUSION: The results show that GSE phenolics at a concentration over 250 µg ml−1 can have measurable effects on microbial activity in an in vitro fermentation system, as evidenced by the changes in kinetics and end-products from starch fermentation. This suggests that fermentation patterns could be conceivably shifted in the actual GIT, though further evidence will be required from in vivo studies. Copyright © 2012 Society of Chemical Industry