Abstract

Trans-resveratrol (3, 5, 4^' – trihydroxy-trans-stilbene) is a stilbene naturally present in a number of plant families. Berry skins of grape (Vitis vinifera L.), Alicante, Black Malvasia, Nerello and Prunesta cultivars were analyzed at weekly intervals for trans-resveratrol production at five ripening stages during the last five weeks of maturation, from August 26^th to September 23^th. Analysis was carried out using the high performance liquid chromatography-diode array detector (HPLC-DAD) technique after fractioning of trans-resveratrol through a 500 mg C₁₈ column (Solid Phase Isolation – SPI technique). A continuous decrease in trans-resveratrol content in all cultivars was observed during ripening. Alicante had the highest trans-resveratrol content, showing a decrease of 46% from the first to last sampling, while Black Malvasia produced the lowest amount of trans-resveratrol, 4 to 5 times less than Alicante at each sampling date.

Key words: Antioxidants, grape, phenols, stilbenes, trans-resveratrol, high performance liquid chromatograph (HPLC).