Alteration of Antioxidant Activity and Total PhenolicContent during the Eight-Week Fermentation of AppleCider Vinegar

Abstract

Apple is one of the delicious fruit consumed by people. Apple cider vinegarwas made through the traditional method and the changes occurred during the8 week fermentation period were determined in this research. Total titratableacidity, pH, total soluble solids (°brix), total phenolic contents, Oxygen RadicalAbsorbance Capacity (ORAC) and Trolox Equivalent Antioxidant Capacity(TEAC) assays, phenolic contents were determined. Total phenolicsubstance, ORAC and TEAC values increased significantly weekly andreached the highest level in the $3^{rd}$ week. Total phenolic substance, ORACand TEAC values of $3^{rd}$ week apple vinegar were determined as1110.63 mg GAE $L^{-1}$ , 10.92 mM and 21.11 µmol TE $mL^{-1}$ , respectively. Applevinegar samples had gallic acid, catechin, epicatechin, chlorogenic acid, andp-coumaric acid. The major phenolic substances in apple vinegar were gallicacid and chlorogenic acid. While gallic acid value of 3rd and 4th week applevinegar were detected 11.91 and 23.69 mg $L^{-1}$ , respectively; chlorogenic acidvalue of 4th and 5th week apple vinegar were found 46.36 and 49.71 mg $L^{-1}$ .Antioxidant activity and phenolic substances values were not significantreduction during the acetic acid fermentation. In this study, the formationprocess of the functional and sensory properties of apple cider vinegar due tothe change in the weekly antioxidant and bioactive component content ofapple cider vinegar was emphasized.