Bioactive compounds and total antioxidant capacity of cane residues from different grape varieties

Abstract

Every year the viticulture activity generates considerable amounts of underused lignocellulosic residues as grape cane that generally are composted or burned despite their potential value as a source of bioactive compounds. To know their phytochemical composition and total antioxidant capacity (TAC) may be a useful way of exploiting different high‐added value applications.RESULTS21 phenolic compounds (PC) and two carotenoids (Car) were quantified by high performance‐liquid chromatography‐diode array detection (HPLC‐DAD) in 8 grape varieties from different locations in Mendoza, Argentina. The maximum concentrations corresponded to the stilbene ε‐viniferin (10552 μg g‐1 DW), followed by the flavanols (+)‐catechin (3718 μg g‐1 DW) and (‐)‐epicatechin (2486 μg g‐1 DW). As well, lutein and β‐carotene were quantified at levels ranged between 350 and 2400 ng g‐1 DW. The TAC of the extracts was assessed by ORAC, ABTS and DPPH assays, with a good correlation between TAC and total PC for each sample (r ≥ 0.82).CONCLUSIONSamples of cv. Malbec, the most representative variety of Argentina´s winemaking industry, presented high contents of PC, particularly ε‐viniferin, (+)‐catechin and (‐)‐epicatechin. Quercetin‐3‐galactoside, OH‐tyrosol and Car were reported for the first time in grape canes of the 8 varieties. The results add knowledge related to this inexpensive source of high value bioactive compounds which could be used as functional ingredients.