Sherry wine vinegar:: physicochemical changes during the acetification process

The quality of a sine vinegar is determined by the raw wine substrate and the acetification process employed in its production. Attempts to characterise vinegars have been based on these two features, along with variables such as total extract, glycerol, organic acids, volatile compounds and phenolic composition. When the final products are analysed, it is difficult to evaluate to what extent quality differences are due to the raw material or to differences in production methods, so it is necessary to determine the influence of each feature separately. The present work focuses on monitoring physicochemical changes during the acetification of sherry wine by submerged culture. ANOVA showed significant differences for ethanol, acetic and lactic acids and some volatile compounds (methanol, l-propanol, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, acetoin, acetaldehyde, ethyl acetate and ethyl lactate). However, no statistical changes were found for phenolic compounds during acetification. The phenolic composition of the final product was determined by the substrate employed. In addition, the influence of cycle duration on the chemical composition was studied; the only compound affected by this factor was 2-methyl-1-butanol. (C) 2001 Society of Chemical Industry.