In vitro gastrointestinal digestion of Hibiscus sabdariffa L.: The use of its natural matrix to improve the concentration of phenolic compounds in gut

Hibiscus sabdariffa L (Malvaceae) is rich in organic acids, vitamin C, fiber and phenolic compounds and its consumption as an infusion prepared with the dehydrated calyx is widely documented to have an inverse relationship with the incidence of chronic and degenerative diseases. The exhausted calyx is usually discarded so the aim of this work is to propose the use of the whole calyx as a natural carrier of polyphenols in order to increase their bioaccesibility in gut, showing that digestion extracts more phenolic compounds than the simple infusion process with the added benefit of fiber ingestion as well. It is also proposed an alternative to already documented in vitro digestion procedure that allows the samples to be analyzed without pretreatments. In vitro digestion behavior is graphically shown and statistically significant correlations between total polyphenol count and both antioxidant activity methods used (FRAP and DMPD) have been obtained. (C) 2012 Elsevier Ltd. All rights reserved.