Characterization of an Antioxidant-Enriched Beverage from Grape Musts and Extracts of Winery and Grapevine By-Products

Abstract

The recovery of antioxidants from complex winery and grapevine by-products into Vitis vinifera must offers new opportunities for wine grapes by the development of a new, enriched fruit juice. However, this demands the search for new valorization methods to get hold of additional antioxidant compounds. The objective of this study was to find a novel functionality for grape pomace, grapevine leaves, and canes by its reuse as a functional matrix for the extraction of antioxidants into grape must. After thermomaceration, 22 polyphenols were identified by high performance liquid chromatography and mass spectrometry. Grape pomace was a good source of anthocyanins (malvidin-3-glucoside), while flavonols (quercetin-3-hexoside) and phenolic acids (caftaric acid) were the main phenolic compounds in leaf extracts. Catechin dimer was the only polyphenol compound present in all of the matrices. Enriched grape juice comprised by 40:20:40 (v/v/v) of pomace, leaf, and cane extracts, yielded an oxygen radical absorbance capacity of pirogallol red and fluorescein ratio of 0.70, indicating that the reactivity of antioxidants present in enriched grape juice was at least as efficient as other polyphenol-rich beverages. Thus, pomace, leaves and canes supply additional polyphenols to grape must that results into a beverage with promissory antioxidant activity and potential health benefits.

Keywords

• grape juice
• thermomaceration
• antioxidants
• polyphenols
• Vitis vinifera