Vinegar is a widely known fermented product, which is appreciated for its distinct organolectic properties, food preservative features and versatility in modern cooking. It can be obtained from virtually any fermentable carbohydrate, including hydroalcoholic solutions, various fruits, cereals or amidaceous agricultural produces, after a yeast-driven alcoholic fermentation and a subsequent acetification carried out by acetic acid bacteria. However, in Europe, the highest prized quality vinegars derive from grape and wines obtained therefrom, some of them being commercialized under a specific protected designation of origin (PDO) or a protected geographical indication (PGI). Different technological processes are used for their production and, due to this, sensory and constitutive characteristics of the different marketed vinegars largely differ each other. In particular, the composition in amino acids and amines in the final product largely depends on the starting raw material and the microbiota specific of the diverse producing processes. In this work, thirty-six Italian and Spanish vinegars representing all the European DPO or GPI specialties currently marketed, have been analyzed for their content in amino acids and amines, with the aim to characterize the products and provide information on the presence of molecules such as biogenic amines, which may cause adverse physiological effects in sensitive consumers.
A RP HPLC-UV method based on sample pre-column derivatization with diethylethoxymethylenmalonate (DEEMM) was used for the simultaneous quantification of 23 amino acids and 11 biogenic amines.
Based on the entire dataset, Anova and cluster analysis provided a clear discrimination between Italian and Spanish vinegars, while no univocal differentiation was found for vinegars undergone to increasing ageing times. Balsamic vinegar of Modena samples demonstrated to contain the highest amount of aminoacids (being particularly richer in alanine, GABA, threonine and arginine) while Spanish vinegars tended to share higher amounts of putrescine and total amines. Hystamine was found at levels not representing a safety issue for consumers. Serotonine was also detected in all the PDO or PGI vinegars at amounts < 1 mg/L
