The effect of temperature and storage time on the phenolic composition and on the antioxidant activity of grape (Vitis vinifera L.) juices made using a red (Sangiovese) and a white (Muscat of Alexandria) variety was studied. Total phenolics, flavonoids and flavan-3-ols were determined on grape extracts and juices. The antioxidant activity was assessed by means of two different in vitro tests: scavenging of the stable DPPH˙ radical and the inhibition of tyrosine nitration mediated by authentic peroxynitrite (ONOO-). All the juices were analysed after 24 hours and 2 weeks of storage by means of 2-Way ANOVA (factors being cultivar and temperature). Cultivar effect proved to be highly significant, while no significant differences in the phenolic composition were observed for storage temperatures (4°C and -20°C) and cultivar x temperature interaction. However, when statistical analysis was focused on each cultivar, Muscat of Alexandria was found to be more sensible to storage conditions and a significant reduction in total phenolics (-20%) and flavonoids (-53%) content and in the ONOO- scavenging potential (-32%) was evident after 2 weeks at 4°C (when compared with the same storage temperature after 24 hours). On the contrary, Sangiovese juices did not show significant differences among the four storage treatments investigated. These results could be explained suggesting that anthocyanins presence in red grape play a key role in juice stability.
|Autori:||Genova, G.;Iacopini, P.;Baldi, M.;Ranieri, A.;Storchi, P.;Sebastiani, L.|
|Data di pubblicazione:||2012|
|Titolo:||Temperature and storage effects on antioxidant activity of juice from red and white grapes|
|Rivista:||INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY|
|Appare nelle tipologie:||1.1 Articolo in rivista|