engleski

Changes in total phenolics, total anthocyanins, and antioxidant activity during ripening of grapes

Grape berries, variety Limberger, produced in two vineyards (Ilok and Feričanci) located in eastern part of Croatia (Slavonia) during 2010. year were analysed for total polyphenols (TP), total anthocyanins (TA), and antioxidant activity (AOA) during the berry ripening. The main objective of this study was to investigate the influence of grape maturity on total polyphenolic and total anthocyanins content, as antioxidant activity of the grapes, their mutual relation, and relations with pH, sugar content, and weather conditions. Significant correlation between TP and TA was observed only for the grapes from Ilok (r = 0.92). Good correlation was found for the TA and sugar content in grapes (r = 0.90 Ilok, r = 0.83 Feričanci), TA and pH (r = 0.89 Ilok, r = 0.80 Feričanci), and between TA and daily mean temperature (r = 0.70 Feričanci, r = 0.89 Ilok). Significant correlation was not observed between AOA and total polyphenols (r = 0.69, Ilok ; r = 0.24, Feričanci). Slightly higher correlation was observed between antioxidant activity and total anthocyanins content (r = 0.73, Ilok ; r = 0.49, Feričanci). Those results imply on conclusion that antioxidant activity of grapes have a relation with group of polyphenols with high antioxidant activity and which concentration declines after vérasion.

Grape ripening ; phenolics ; antioxidant activity

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