Improved extraction of resveratrol and antioxidants from grape peel using heat and enzymatic treatments.

BACKGROUND: Resveratrol, an extensively recognized phytochemical that belongs to the stilbene family, is mainly abundant in grape peel and dematerializes as a by-product during grape juice processing.

RESULTS: In this study, we established that pre-heating grape peel at above 75°C significantly improved the extractability of resveratrol and its glucoside piceid. In particular, thermal heating of grape peel at 95°C for 10 min, followed by treatment with a mixture of exo-1,3-β-glucanase and pectinases at 50°C for 60 min, dramatically increased the conversion of piceid into resveratrol and the overall extractability of this phytochemical by 50%. Furthermore, thermal pre-treatment promoted the substantial increase in the total phenol, flavonoid, and anthocyanin concentrations in the grape peel extract. Ultimately, resveratrol-enriched grape peel extract (RES-GPE) significantly augmented the antioxidant response in vitro, possibly by attenuating the accumulation of intracellular reactive oxygen species via the Nrf2 signaling pathway.

CONCLUSION: The method developed in this study for preparing grape peel extract introduces a potential low-cost green processing for the industrial fortification of food products with resveratrol and other health-beneficial antioxidants. This article is protected by copyright. All rights reserved.