A preliminary study of non-coloured phenolics in wines of varietal white grapes (cَdega, gouveio and malvasia fina): effects of grape variety, grape maturation and technology of winemaking

The effects of cultivar, grape maturation and technology of winemaking on the levels of phenolic acids were evaluated. In all varieties, 3,4-dihydroxybenzoic, p-coumaric and caffeic acids were the predominant acids. Among the three varieties, significant differences were observed in the concentration of p-coumaric acid. The grape maturation only influenced the concentration of 3,4-dihydroxybenzoic acid. According to the technology of winemaking, significant differences could be observed in syringic, and p-coumaric acids by the induction of fermentation temperature. Comparisons of the phenolic composition, when the fermentations were conducted in stainless steel tanks and/or in oak barrels, showed differences in the concentrations of 3,4-dihydroxybenzoic, ellagic and caffeic acids.