Effect of temperature and time on the phenolic extraction from grape canes

Grape canes from Vitis vinifera L. cultivars of Campania region (Italy): "Aglianico", "Fi-ano", and "Greco" were considered in order to valorise them through the extraction of phenolic compounds provided with antioxidant activity. Since many operational parame-ters influence the extraction process, here different extraction conditions were compared. Grape canes (5% w/v) were extracted in water at different temperatures (25, 50, 75 and 100°C) and extraction times (10, 20, 40 and 60 min). The highest yields, in terms of mg/g dry extract, were obtained by "Greco" at 100°C and 20 min: 110.51±5.46 for total phe-nols, 63.29±1.35 for ortho-diphenols, 77.31±3.59 for tannins, and by "Greco" at 50°C and 40 min for flavonoids: 29.37±0.73. The extracts from "Greco" at different tempera-tures showed antioxidant activity comparable to that of butylhydroxytoluene and querce-tin chosen as reference compounds. HPLC analysis revealed that gallic acid and catechin were the most abundant phenolic compounds detected in the extracts.