Changes Of Phenolic Components During The Development Of Wine Grape Berries

Phenolics are very important component of grape and wine, which contribute to such characteristics of wine as colour, flavour, astringency and bitterness. In this study, we analyzed the components and contents of phenolic compounds in grape skins and seeds of three wine grape varieties(Vitis vinifera cv. Cabernet Sauvignon, Merlot, Marselan) during berry development and ripening with HPLC technology. Then, the phenolic differences between skins and seeds were compared, discussing theoretically the change law of phenolics with the fruit development. The results were shown as follows:(1) Overall, the contents of total phenolics, tannin and total flavonoid of skins and seeds gradully decreased during berry development, while rise slightly before harvest. The accumultion of total anthocyanins in skins presents the trend of rise-fall during fruit ripening. The amount of phenolics was significantly different among grape varieties. The contents in seeds were significantly higher than skins.(2) Nine anthocyanins in three grape cultivars skins were analyzed. Malvidin-3-O-glucoside, the main anthocyanin component in grape skins, accounted for 30%-45% of the total anthocyanins. The contents of anthocyanin compounds in the skins increased from the onset of veraison, and then trended to be stable before harvest. The change of 9 anthocyanins was different in three grape cultivares. The composition proportion of anthocyanins for one variety remain unchanged, during maturity, which was not affected by the change of content.(3) There were 9 anthocyanins in seeds of tested varieties while stibene was not detected. The change of gallic acid, chlorogenic acid, ferulic acid,(+)-catechin and(-)-epicatechin were obvious during the ripening. Phenolics such as gallic acid, chlorogenic acid and epocatechin showed trend of rising, while others did downward. The common point was that their contents changed dramatically before and after verasion.The contents of chlorogenic acid, ferulic acid and(-)-epicatechin of skins presented a downward trend. Overall the contents of non-anthocyanin phenolics of skins had amodest rise before harvest. Content of trans-resveratrol was less or trace during young fruit period, increased rapidly after veraison, then fell slightly before harcest.