Total phenolics, flavonoids, anthocyanins and antioxidant activity following simulated gastro-intestinal digestion and dialysis of apple varieties: Bioaccessibility and potential uptake

Jaouad Bouayed; Lucien Hoffmann; Torsten Bohn

doi:10.1016/j.foodchem.2011.02.052

Total phenolics, flavonoids, anthocyanins and antioxidant activity following simulated gastro-intestinal digestion and dialysis of apple varieties: Bioaccessibility and potential uptake

Food Chem. 2011 Sep 1;128(1):14-21. doi: 10.1016/j.foodchem.2011.02.052. Epub 2011 Feb 17.

Authors

Jaouad Bouayed¹, Lucien Hoffmann¹, Torsten Bohn²

Affiliations

¹ Centre de Recherche Public - Gabriel Lippmann, Environment and Agro-Biotechnologies Department, 41, rue du Brill, L-4422 Belvaux, Luxembourg.
² Centre de Recherche Public - Gabriel Lippmann, Environment and Agro-Biotechnologies Department, 41, rue du Brill, L-4422 Belvaux, Luxembourg. Electronic address: bouayedj@yahoo.fr.

PMID: 25214323
DOI: 10.1016/j.foodchem.2011.02.052

Abstract

In the present study, an in vitro model simulating gastrointestinal (GI) digestion, including dialysability, was adapted to assess free soluble polyphenols from apples (four varieties). Results indicated that polyphenol release was mainly achieved during the gastric phase (ca. 65% of phenolics and flavonoids), with a slight further release (<10%) during intestinal digestion. Anthocyanins present after the gastric phase (1.04-1.14mg/100g) were not detectable following intestinal digestion. Dialysis experiments employing a semipermeable cellulose membrane, presenting a simplified model of the epithelial barrier, showed that free soluble dialysable polyphenols and flavonoids were 55% and 44% of native concentrations, respectively, being approximately 20% and 30% lower than that of the GI digesta. Similar results were found for the antioxidant capacity of dialysable antioxidants, being 57% and 46% lower compared to total antioxidants in fresh apples (FRAP and ABTS test, respectively). It is suggested that some polyphenols are bound to macromolecular compounds that are non-dialysable, that the presented method allowed the study of free soluble polyphenols available for further uptake, and that both chemical extraction and concentrations in final digesta would overestimate polyphenol availability.

Keywords: Anthocyanins; Antioxidant activity; Antioxidants; Apples; Bioaccessibility; Dialysability; Flavonoids; Gastro-intestinal digestion; Polyphenols.