Fate of polyphenols in pili (Canarium ovatum Engl.) pomace after in vitro simulated digestion

ABSTRACT

Objective To evaluate the stability and bioavailability of polyphenols in pili (Canarium ovatum Engl.) pomace during simulated in vitro digestion. Methods Freeze-dried pili pomace was subjected to in vitro digestion simulating conditions in the stomach, small intestine and colon. Total polyphenols, anthocyanins, flavonoids and condensed tannins, and its antioxidant activity – 1,1-diphenyl-2-picrylhydrazyl, 2,2′-azinobis-3-ethylbenzothiozoline-6-sulfonic acid, and ferric reducing antioxidant power were measured using standard spectrophotometric methods. Results In vitro digestion of pili pomace resulted in reduction of phenolic compounds. Condensed tannins and anthocyanins were released in the gastric and intestinal stages, while total polyphenols and flavonoids after fermentation simulating colonic conditions. Antioxidant values of the bioavailable fractions showed that more than 90% of activity was lost during simulated digestion. Conclusions Findings indicate that pili pomace is a promising functional ingredient for food and dietary supplements which can furnish potentially bioavailable phenolic antioxidants to the body.