Effects of weather conditions and aging on resveratrol concentration in red wines
2002
Yasui, Y. (Tokachi-Ikeda Research Inst. for Viticulture and Enology, Hokkaido (Japan)) | Yunoki, K. | Naito, A. | Kawaguchi, M. | Ohnishi, M.
Resveratrol (RT) has been suggested to have a protective effect against cardiovascular diseases.We analyzed the concentration of RT in red wine samples at early stages of aging and old vintage wines, by a combination of normal and reverse phase HPLC. Although we have previously reported that RT contents in red wine samples, made from eight grapevines grown in Hokkaido, Japan, after malolactic fermentation were generally higher than those measured at the end of alcoholic fermentation, the increasing level of RT in the wines was shown to continue until 8 months after malolactic fermentation accompanied by a decrease in piceid (RT glucoside) probably due to B-glucosidase produced by lactic acid bacteria. During further storage period the RT level was presumed to little change. In analysis of red vintages (from 1982 to 1992) made from the same grapevine, considerable amounts of RT (1.8-3.5mg/l) were present. Although there was a decrease of cis-RT content with aging years, there was no correlation between trans-RT content and aging years, suggesting that trans-RT level in wines would be stable during aging period. The relationship between trans-RT levels in the vintages and weather conditions at the vineyard from June to September of harvest years showed trend where the concentrations of trans-RT decreased when the temperature was high. Thus, it was found that much of the variation in RT content in red wines, reported in the literature, could be partially explained by weather conditions during the grape berry development as well as by intrinsic properties of grapevines from which wines were vinted.
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