Characterization of Grape and Apple Peel Wastes’ Bioactive Compounds and Their Increased Bioavailability After Exposure to Thermal Process

Abstract

80% of the grape harvest is used in the winemaking industry, resulting in huge amounts of waste which are still rich in phenolic compounds, while the same percentage of polyphenols are found in apple peel, whose total antioxidant capacity is five-to-six-fold higher than that of apple flesh. The aim of this research is the characterization of grape and apple peels waste, before and after the thermal treatment (10 minutes, 80°C), with respect to its bioactive compounds to evaluate their potential enhancement with respect to bioavailability. Based on the obtained results, the highest antioxidant activity and phenolic content was exhibited by thermally processed red-grape waste. After the thermal treatment, the caffeic acid 4-O-glucoside increased with a 27% in apple waste. As a conclusion, the grape and apple peels waste can be exploited for their bioactive compounds after the thermal process, whose bioavailability increased and can be added in food formulations as health promoting products.