Study On The Phenolic Acids In Wines And Phenylpropanoid Metabolism In Grape Berries

A new method of reversed phase high performance liquid chromatography (RP-HPLC) for simultaneously determination of 11 phenolic acids in wines and grape berries was established. Used 12 different wines manufactured in China and two common varieties of grape berry as materials, 11 phenolic acids were deterimated. The results were as follows: the main phenolic acids in wines were gallic acid, gentisic acid, caffeic acid, p-coumaric acid, syringic acid and protocatechuic acid, compared with white wines, the contents of total hydroxybenzoic acids, total hydroxycinnamic acids and total phenolic acids were higher in red wines; the contents of phenolic acids among the experimented wines that vintaged in different years by the same manufacturer had little changes; the contents of 11 phenolic acids in different wines were different. In grape berry, gallic acid, caffeic acid, gentisic acid, protocatechuic acid, syringic acid and pcoumaric acid were the main phenolic acids, moreover, the contents of phenolic acids in pulp were higher than in pericarp.Used Cabernet Sauvignon red wines and Chardonnay white wines as materials, changes of 11 phenolic acids during fermentation and aging process were assessed in this study, also the effect of three different oak barrels on the contents of 11 phenolic acids was investigated. The results showed that during red wine fermentation, changes of phenolic acids in red and white wine exhibited a similar current; compared with protocatechuic acid, p-hydroxybenzoic acid, vanillic acid, chlorogenic acid, ferulic acid and sinapic acid, gallic acid, gentisic acid, syringic acid, caffeic acid and p-coumaric acid changed sharply, contents of total hydroxybenzoic acids, total hydroxycinnamic acids and total phenolic acids firstly increased and reached a high level, then kept constant; aging in three oak barrels, gallic acid, gentisic acid, protocatechuic acid, caffeic acid and p-coumaric acid had more changes, while p-hydroxybenzoic acid, vanillic acid, syringic acid, chlorogenic acid, ferulic acid and sinapic acid had little changes; the effect of different oak barrels on phenoic acid was different with different aging time, aging in American and Occident oak barrels exhibited fast effect, while aging in European oak barrel had slow effect.No reports about phenylpropanoid metabolism of fruit have been examined in detail. Using grape berries (Vitis vinifera L. cv. Cabernet Sauvignon) as materials, this study assessed changes of 11 phenolic acids and selected key enzymes known to be involved in phenylpropanoid metabolism during berry development. Subcellular localizations of the selected enzymes in berry were also studied by immuno-gold electron microscopic technique. Contents of gallic acid, protocatechuic aicd, gentisic acid and caffeic acid changed drastically during berry development, while contents of p-hydroxybenzoic acid, vanillic acid, syringic aicd, chlorogenic acid, p-coumaric acid, ferulic aicd and sinapic acid varied relatively slightly. Activities of phenylalanine ammonia-lyase (PAL), cinnamate-4-hydroxylase (C4H) and 4-coumarate: coenzyme A ligase (4CL) had two peaks and changed concomitantly during berry development, furthermore, their activities were significantly correlated with total phenolic acids contents. Western blotting analysis showed that protein amounts did not fully correlate with enzymes activities, a PAL isoenzyme was detected in berries and its expression was special. Immunolocalizationexperiments revealed that PAL mainly distributed in cell walls, secondary thickened walls, parenchyma cells of berry mesocarp cells; C4H mainly distributed in chloroplast (plastid), nucleus; 4CL mainly distributed in secondary thickened walls, parenchyma cells of mes ocarp vascular tissue.Used grape berry (Vitis vinifera L. cv. Cabernet Sauvignon) of Veraison and post-harvest as materials, performed with the in vivo pre-incubation of the grape berry tissues in the SA-contained medium and the in vivo infiltration of SA into the entire berries, the effects of SA on the phenylpropanoid metabolism...