Influence of vintage and variety on phenolic compounds of Brazilian red wines from a new wine-producing region

Abstract

Phenolic compounds, specially flavonoid compounds, are one of the most important parameters in assessing the quality of wines and possible responsible for beneficial properties of wines. Thus, the influence of vintage and variety on the main flavonoid compounds are evaluated in Vitis vinifera L wines cv. Cabernet Franc, Merlot, Sangiovese and Syrah, 2006 and 2007 vintages, produced in São Joaquim, a new wine-producing region in southern Brazil. The levels of the main flavan-3-ols monomers (catechin, epicatechin, gallocatechin, epigallocatechin and epicatechin gallate) and proanthocyanidin dimers (B1 and B2);  3-glucoside anthocyanins (delphinidin, cyanidin, petunidin, peonidin, malvidina) and flavonols (myricetin, quercetin, laricitrin, kaempferol, isorhamnetin and syringetin) are studied by HPLC-DAD and/or HPLC-DAD-MS. Two-way ANOVA analysis revealed significant differences (p< 0.05) for the flavonoids composition of wine samples as a function of both variety and vintage factors. Moreover, the results showed catechin and epicatechin were the two main flavan-3-ol monomers in the wine samples, with contents ranging from 4.07 to 34.71 mg L^-1, followed by gallocatechin and epigallocatechin. The total content of PA dimers ranged from 8.75 to 61.34 mg L^-1, and PA B1 was the main dimer. About flavonol contents, quercetin and myricetin were the main compounds, and the concentration of total flavonols ranged from 20.81 to 46.79 mg L⁻¹. The mean total anthocyanins content was 47.43 mg L⁻¹, and ranged from 12.94 to 125.60 mg L⁻¹. The results for the phenolic compounds content of the wine samples were considered appropriate for quality red wines, and, in general, theses concentrations were in line with those reported in the literature from the most renowned regions of premium wine production. These interesting results further support the potential of the region to produce high quality wines.