A Comparison of Green Extraction Techniques for the Recovery of Bioactive Compounds from Grapevine By-Products

Abstract

Different extraction techniques, namely ultrasound-assisted extraction (UAE), microwave-assisted extraction (MAE), subcritical water extraction (SWE), and conventional extraction (CE), were tested to evaluate their efficiency in recovering bioactive compounds from grapevine by-products. SWE was the extraction technique that allowed for the highest recovery of polyphenolic compounds, while grape stalk from the Cerceal Branco variety obtained using SWE at 150 °C had the highest TPC (17.0 ± 0.2 mgGAE/g fw) as well as the highest antioxidant activity from ABTS and FRAP assays (19.9 ± 0.3 and 13.0 ± 0.3 mgAAE/g fw). The phenolic composition revealed high amounts of catechin, epicatechin, chlorogenic, and neochlorogenic acids. SWE was demonstrated to be a powerful extraction technique for the recovery of polyphenols from grapevine by-products.

Keywords

• grapevine by-products
• polyphenols
• green extraction techniques
• functional products