The effect of grape harvest date on polyphenols and anthocyanins content of different red grapes varieties

Abstract

Four red grape cultivars were investigated in order to study the effect of grape harvesting date (ripening stage of the grape) on traditional indicators of maturity such as soluble solids and titratable acidity content, as well as on their total polyphenols and total anthocyanins content. Grape varieties grown in different coastal vinegrowing regions, at three different harvesting dates, and from two consecutive vintages, were examined. The results showed uncertainty of traditional indicators of maturity as the only parameter for harvest date determination, since the maximum concentration of soluble solids didn’t correlated with maximum concentration of total polyphenols and anthocyanins in the most of harvest dates. Furthermore, grapes from the third harvest date mostly didn’t have consistently higher polyphenols and anthocyanins levels, so the harvest should not be postponed unduly.

Keywords

• anthocyanins
• harvest date
• polyphenols
• red grapes