Bioaccessibility of phenolic compounds during simulated gastrointestinal digestion of black rice (Oryza sativa L., cv. Artemide)
Antonio Colasanto, Vincenzo Disca, Fabiano Travaglia, Matteo Bordiga, Jean Daniel Coïsson, Marco Arlorio, Monica Locatelli
Abstract
Black rice can be defined as a natural functional food, due to its high content of antioxidant polyphenols, particularly anthocyanins and phenolic acids. The objective of this study was to assess the fate of the main phenolic compounds in cooked black rice through in vitro digestion, defining both their soluble and insoluble fractions at the different digestive phases. The digestion significantly impacted the stability of the molecules, more specifically anthocyanins, which tend to be stable up to the gastric level and then degrade during the intestinal phase; after gastrointestinal digestion the total recovery of cyanidin-3-O-glucoside, the most abundant anthocyanin, was 52.4 %. On the other hand, bioaccessibility of free phenolic acids progressively increases up to the intestinal phase, with a total recovery of protocatechuic acid, the most represented phenolic acid in free form, of 84.3 %. Finally bound phenolic acids were not significantly released during the digestive phases. • Bioaccessibility of anthocyanins increased up to the gastric phase. • Glycosylation influences the stability and bioaccessibility of anthocyanins. • Gallic acid increased during digestion up to a final recovery >300 %. • Bound phenolic acids are not affected by digestion conditions. • Bound catechin was stepwise released during GI digestion.