Sherry wine vinegars: phenolic composition changes during aging

Abstract Production of Sherry wine vinegar encompasses a variable period of aging in wood. Changes in phenolic compounds during Sherry vinegar aging were studied. Samples were divided according to their aging period in wood (less than 2 years, more than 2 years) and phenolic compounds determined in a total of 38 samples by means of HPLC and Photodiode Array Detection. Results of Multiple Analysis of Variance (MANOVA) confirms that there were significant differences among both groups. Good recalling rates were achieved in both Linear Discriminant Analysis LDA (mean=92.9%) and Artificial Neural Networks trained by Back Propagation (BPANN) (mean=90.4%) whilst prediction abilities are more discrete. Applying the forward selection of variables, six variables were selected according to the Wilks' lambda criterion: gallic acid, 5-hydroxymethylfuraldehyde, coumaroyltartaric acid glycoside, p-hydroxybenzoic acid, caffeic acid and isoquercetrin. Three of these compounds (gallic acid, hydroxymethylfuraldehyde and coumaroyltartaric acid glycoside) were shown to have an increasing trend through most aging systems.