Changes in physicochemical characteristics, polyphenolics, and amino acids of wax apple cider vinegar during prolonged storage

Several quality attributes of wax apple cider vinegar (WACV) were determined every 30 days for six months at ambient temperature. Acetic acid fermentation significantly increased the acetic acid content in WACV. The lightness and yellowness gradually decreased, whereas redness increased during storage. Density, viscosity, and pH of WACV continuously retarded, and total acidity, volatile acidity, electrical conductivity, and total nitrogen content increased during storage. Phenolic and flavonoid contents and antioxidant potentials of WACV were affected by storage. Various amino acids and volatile compounds were observed in WACV during storage. Throughout the storage period, the microbial growth in WACV was considerably low.