Revealing release patterns and availability of phenolics in Tartary buckwheat under simulated digestion

Abstract

The release patterns of phenolics in digestive tract was elucidated using a simulated digestion protocol, in which the delivery route of rutin was revealed, and the availability of released phenolics was also evaluated using a dialysis membrane absorption model. The results showed that phenolic compounds such as rutin, quercetin, 3,4-dihydroxybenzoic acid (DA), 2,3,4-trihydroxybenzoic acid (TA) and chlorogenic acid (CA) were released from Tartary buckwheat under simulated digestion. The contents of released phenolic compounds in oral-gastrointestinal digestion were significantly higher (p < 0.05) than that in oral and oral-stomach digestion phases. Besides, in oral-gastrointestinal digestion, the proportion of available contents of rutin, DA, TA and CA to corresponding released contents were 71.8%, 73.7%, 68.6% and 100%, and the great majority of rutin was sufficiently degraded into quercetin. The contribution of antioxidant activity of available compounds to corresponding total activity were between 62.2% and 68.9%. These results indicated that phenolics in Tartary buckwheat can be adequately released in oral-gastrointestinal digestion, and a great majority of these phenolics are available. This study illustrates the potential bioavailability of phenolic compounds in Tartary buckwheat during gastrointestinal digestion.