Effects of subcritical water extraction and cultivar geographical location on the phenolic compounds and antioxidant capacity of Quebranta (Vitis vinifera) grape seeds from the Peruvian pisco industry by-product

Abstract

The objectives of this study were to evaluate the effects of the grape cultivar geographical location and extraction technique on the total phenolic compounds (TPC), antioxidant capacity (AC), oil yield and quality of Quebranta (Vitis vinifera) grape seeds. Seeds were defatted with supercritical CO<inf>2</inf> and the bioactive compounds were extracted with subcritical water and macerations with methanol, ethanol, and acetone. The differences in grape seed oil yield were not significant (p > 0.05). The most abundant fatty acid determined was linoleic (66.37-67.37%). The highest TPC corresponded to the extracts from zones A and B obtained with subcritical water, 167.56 ± 10.40 and 161.83 ± 4.95 mg GAE/g dw, respectively. The highest AC by DPPH was also achieved by the extracts from zones A and B (1,479.90 ± 12.86 and 1,628.15 ± 80.32 µmol TE/g dw, respectively) with subcritical water extraction. The highest AC by FRAP was observed in the subcritical water extracts from zones B and C, 1,429.29 ± 29.75 and 1,389.54 ± 7.46 µmol TE/g dw, respectively. Grape seed is a valuable source of nutritionally oil and bioactive compounds, which can be obtained from by-products of pisco production for potential use in the food and pharmaceutical industries. © 2022 Elsevier B.V., All rights reserved.