IMPACT OF IN VITRO DIGESTION PHASES ON ANTIOXIDANT PROPERTIES OF MONASCAL WAXY CORN FROM 2-STEP FERMENTATION

Abstract

The stability of monascal waxy corn (MWC) during in vitro digestion of MWC on bioaccessibility, using a standardized in vitro gastrointestinal digestion was focused on DPPH free radical scavenging ability, chelating ability on Fe2+, monacolin K and citrinin content of MWC fermented by Monascus purpureus TISTR 3090. The simulation of in vitro digestion was comprised of two stages: gastric and intestinal digestion. The results were found that, after gastric digestion, monacolin K and citrinin contents, DPPH free radical scavenging ability and chelating ability on Fe2+ of MWC of the sample were increased 1.35, 8.69, 33.33 and 13.47 %, respectively, suggesting a release of high potential antioxidants. After pancreatic digestion, however, monacolin K and citrinin contents and DPPH free radical scavenging ability and chelating ability on Fe2+ between soluble and insoluble MWC were decreased between 14.69 and 76.92 % which these values were lost during treatment with pancreatin. It indicated that pancreatic digestion causes reduced antioxidant activity between soluble/insoluble fractions while the gastric digestion promoted more releasing the antioxidant activities.