Phenolic compounds content and antioxidant activity in pomace from selected red grapes (Vitis vinifera L. and Vitis labrusca L.) widely produced in Brazil

TLDR

The study examined the phenolic content and antioxidant activity of pomace from four widely produced Brazilian grape varieties to evaluate their potential as natural antioxidant sources. Cabernet Sauvignon pomace had the highest total phenolics (74.75 mg GAE/g), antioxidant activity (ABTS 485.42 µmol TEAC/g, DPPH 505.52 µmol TEAC/g), and reducing power (FRAP 249.46 µmol TEAC/g), while Bordeaux pomace showed the greatest oxidation inhibition (41.13%) and anthocyanin content (29.17 mg/g); catechin was the most abundant non‑anthocyanic compound across all varieties, indicating that Cabernet Sauvignon and Bordeaux pomaces are promising sources of antioxidants and natural colorants.

Abstract

The phenolic compounds content and antioxidant activity of pomace from the vinification of grape varieties widely produced in Brazil (Cabernet Sauvignon, Merlot, Bordeaux and Isabel) were investigated with a view to their exploitation as a potential source of natural antioxidants. Cabernet Sauvignon grape pomace was found to have the highest content of total phenolic compounds (74.75 mg gallic acid equivalent (GAE)/g), the highest antioxidant activity (determined using the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging methods; 485.42 and 505.52 μMol Trolox equivalent antioxidant capacity (TEAC)/g, respectively), and the highest reducing power (determined using the FRAP method; 249.46 μMol TEAC/g). The Bordeaux variety showed the highest oxidation inhibition power (41.13%), determined using the β-carotene/linoleic acid method and the highest content of total anthocyanins (HPLC; 29.17 mg/g). Catechin was the most abundant non-anthocyanic compound identified in the grape pomace (150.16 mg/100 g) for all varieties. In this study, pomaces of the red wine vinification of Cabernet Sauvignon and Bordeaux varieties showed the highest potential as a source of antioxidant compounds and natural colourants, respectively.