Principal phenolic compounds in Greek red wines

Polyphenolic substances are of profound significance to both the technological and nutritional value of grapes (Vitis vinifera sp.) and wines. The Hellenic vineyard embraces a large number of native cultivars, with various phenolic contents, which are mostly unexploited. For this reason, 20 red wines, including nine made by rare native Greek varieties, were assayed for their polyphenolic content, using high performance liquid chromatography coupled with a diode array detector. All wines examined were produced under identical enological practices within the premises of the Wine Institute of Athens, so that the observed differences were related to grape variety and geographical origin (in some cases). The results showed that some of the unexploited rare native varieties (e.g., Karvouniaris, Thrapsa, Nerostafilo, Bakouri, Vertzami) contained appreciable amounts of non-colored phenols as well as anthocyanins meaning that they would be worthy of further study and use for the production of quality wines. Karvouniaris, Thrapsa and Augoustiatis were found high in phenolic acids and flavanols but low in flavonols and hydroxycinnamic acids. Nerostafilo and Bakouri were also rich in phenolic acids and flavanols but the former was poor in flavanols and the latter poor in hydroxycinnamates. Finally, by applying PCA to the results some grouping was observed.