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The effect of the main grape organic acids (tartaric, malic and citric) on the degradative oxidation of red wine was investigated by NMR, HPLC and spectrophotometry. Wines featuring the same pH value of 3.2 with different combinations of organic acids were prepared. Results showed that tartaric acid preserved native anthocyanins from oxidative degradation more than malic and citric acids, with malic acid being the one favoring oxidations the most and, consequently, acetaldehyde production. Wines richer in malic acids showed the highest reactivity towards saliva proteins and a potential higher astringency. Given the wide changes in tartaric/malic acid ratio with climate, these results can help to act in vineyard, as well as in winery, to manage the malic/tartaric acid ratio with the aim of improving red wine longevity. [ABSTRACT FROM AUTHOR]

Three Southern Italy red wines Aglianico, Casavecchia and Pallagrello with high content of total tannins but different initial anthocyanins composition were aged in bottle for 15 months with closures allowing different degrees of wine oxygen exposure. In all wines oxygen exposure resulted in a progressive decrease in monomeric anthocyanins, vanillin reactive flavans and content of tannins reactive toward salivary proteins. In contrast, no significant decrease in color intensity was detected due to the formation of polymeric pigments. For all wines, the closure with the highest oxygen ingress determined a higher intensity of red fruit notes. [ABSTRACT FROM AUTHOR]