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Different concentrations of grape seed extract affect in vitro starch fermentation by porcine small and large intestinal inocula


Dongjie Wang, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia. E-mail:


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 NHequation image) 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