Preliminary study of flavonols in port wine grape varieties

Seven varietal port wine grapes (Tinta Roriz, Tinta Barroca, Tinta Amarela, Tints Cao, Touriga Francesa Touriga Nacional and Rufete) were analysed in order to determine differences in flavonol compositions. For this purpose. a SPE-HPLC method was applied. Although no qualitative variations were foun d. there are quantitative differences in the individual concentrations of t he phenolic compounds. In Tinta Cao and Rufete varieties. (-)-epicatechin w as the major compound. All samples showed significant amounts of kaempferol 3-glucoside and isorhamnetin 3-glucoside, with the exception of Rufete var iety, where these compounds were present in traces. (C) 2001 Elsevier Scien ce Ltd. All rights reserved.