Phenolic composition and total antioxidant capacity analysis of red wine vinegars commercialized in Portuguese market

In the last years, there has been an increase in consumption of wine vinegars in Portugal. Thus, the aim of this work was to evaluate the phenolic composition and total antioxidant capacity from several commercial red wine vinegars commercialized in Portuguese market. Several parameters were evaluated: general phenolic composition, chromatic characteristics, individual anthocyanins and phenolic acids by HPLC, and total antioxidant capacity by two methodologies (DPPH and ABTS). For the different parameters analyzed, the red wine vinegars samples studied differed significantly. Vinegars with higher phenolic content tend to have lower lightness, but higher values of the red component color. High diversity of anthocyanins was detected, with some of the vinegars being distinguished by having significantly higher values of anthocyanins compared to the others, as was detected for the generality of the other phenolic parameters. The total antioxidant capacity was positively correlated with the different phenolic parameters. Finally, higher total antioxidant capacity was detected for the phenolic fraction containing anthocyanins and polymeric proanthocyanidins. The results obtained confirm that red wine vinegars are good sources of phenolic compounds and antioxidants. However, there is a great diversity of values for the various red wine vinegars commercialized in the Portuguese market.