Bioaccessibility, changes in the antioxidant potential and colonic fermentation of date pits and apple bagasse flours obtained from co-products during simulated in vitro gastrointestinal digestion

• In vitro gastrointestinal digestion (GID) of date pits (DPF) or apple bagasse (ABF) flours was analysed
• Polyphenolic compounds were sustained released from DPF and ABF
• Polyphenolic bioaccessibility was higher in ABF than DPF
• Antioxidant activity of DPF and ABF was evaluated in each step of GID
• The antioxidant activity could be attributed to the high content of polyphenolic compounds

The aims of this work were to evaluate the effect of in vitro gastrointestinal digestion (GID) on (i) the recovery and bioaccessibility indexes, (ii) the changes on antioxidant activity and (iii) the short chain fatty acid (SCFA) production of two DF rich extracts (date pits flour (DPF) and apple bagasse flour (ABF)) obtained from agro-industrial co-products. At the end of GID process, the bioaccessibility of phenolic compounds present in DPF and ABF was 78.54 and 91.58%, respectively. With regard to antioxidant activity, GID increased the chelating activity and reducing power. However, the scavenging properties were reduced. Fermentation of DPF and ABF by colonic bacteria generated SCFA such as formiate, succinate, acetate, propionate and butyrate. These findings suggest that DPF and ABF might be used as potential food ingredients due to GID produced that bioactive compounds released from the matrix which exerts antioxidant activity.