Matrix composition effect on the digestibility of carob flour phenols by an in-vitro digestion model

Carob flour (CF) and washed carob flour (WCF) (without the water soluble dietary fraction) were submitted to an in-vitro digestion method to evaluate the dietary soluble fibre (DF) and soluble sugars content on the digestibility and bioaccessibility of polyphenols. In addition, combinations of the raw materials (CF and WCF) with hazelnut oil (HO) were proposed in order to evaluate the protection of a vegetable oil rich in polyunsaturated fatty acids (PUFA) on the phenolic compounds submitted to in-vitro digestion conditions. The results showed that the soluble dietary fraction enhanced the stability of the phenolic compounds during the duodenal digestion phase. Similarly, the lipid fraction (rich in PUFA) showed a protective effect on the recovery of the phenolic compounds during duodenal digestion. Disruption of the natural matrix under digestion conditions led to the release of DF and PUFA, which could establish interactions with certain polyphenol compounds enhancing their recovery and stability during digestion.