Phenolic compounds from 'Hass' avocado peel are retained in the indigestible fraction after an in vitro gastrointestinal digestion

Avocado peel is a source of bioactive compounds with antioxidant, anti-inflammatory, antiproliferative and antimicrobial capacities, among others. Physical and chemical interactions of phenolic compounds with indigestible polysaccharides could affect their bioaccessibility in the upper gastrointestinal tract, allowing them to reach the colon, where they exert antioxidant effects and related health effects. The objective of the present work was to evaluate the effect of chemical-enzymatic processes of an in vitro gastrointestinal digestion, on phenolic compounds, antioxidant capacity and chemical constituents of avocado peel, and to determine their content in the indigestible fraction. Results showed that most phenolic compounds resist intestinal digestion (66%), of which 954.72 +/- 19.45 mg GAE/100 g of dry weight (dw) and 250.72 +/- 7.12 mg CE/100 g dw are hydrolysable and condensed tannins, respectively. The highest antioxidant capacity remained in the indigestible fraction (79.4%, 59.8% and 79.6%), with greater predominance in the insoluble indigestible fraction (49.1%, 46.6% and 66.7%) for DPPH, ABTS and FRAP, respectively. Most of the indigestible fraction is insoluble (89.39%), while only 7.46% is soluble. The possible beneficial effects of phenolic compounds and antioxidant capacity of the indigestible fraction of avocado peel must be considered in further studies.

Automated summary

The study evaluated the effects of phenolic compounds, antioxidant capacity, and chemical constituents in avocado peel during in vitro gastrointestinal digestion, and determined their content in the indigestible fraction. Results showed that most phenolic compounds resist intestinal digestion and the highest antioxidant capacity remained in the indigestible fraction.