Effect of oak chips addition on the phenolic composition of grape vinegar in fermentation process.

The phenolic compounds naturally found in vinegar composition have many positive effects on human health. In this research, it was aimed to investigate the effect of adding different amounts of oak chips during the fermentation stage on some physicochemical properties, total phenolic compounds, antioxidant capacity and individual phenolic compounds of grape vinegar. Acetic acid fermentation was carried out by adding oak chips in the amount of 0, 5, 10, 15, 20 g/L to the samples whose alcohol fermentation was completed. In vinegar samples, it was determined that the amount of phenolic compound (1328.96–1782.29 mg GAE/L), antioxidant activity determined by ABTS and DPPH method (1753.50–3258.50 mgTE/L and 199.17–727.78 mg TE/L) increased in parallel with the increase in the amount of oak chips. Ferulic acid and vanillic acid which is individual phenolic compounds, increased depending on raise in the amount of oak chips. In addition, it was determined that there was a significant increase in the amount of gallic acid in vinegar samples compared to wine. This study has shown that the use of oak chips in the acetification stage can save time and can be an alternative to the maturation process using oak barrels. [ABSTRACT FROM AUTHOR]