Production of vinegar from kashar cheese whey and volatile component profile, antibacterial effect, and antioxidant potential of whey vinegar

Whey is a liquid by-product of cheese production and releasing this by-product to the environment as a waste causes environmental pollution, loss of nutritional value, and economic loss. In this study, kashar cheese whey (KCW) and whey supplemented with lactose (5%, 10%, and 15%, w/v) were employed to produce four whey vinegars (KCWV, KCWV 5%, KCWV 10%, and KCWV 15%). Kluyveromyces marxianus CECT 1442 and Acetobacter aceti CECT 298 were used for fermentation. The whey vinegars were analyzed for pH, titratable acidity, lactose and total protein contents, antibacterial activities (agar well diffusion, MIC, MTC, and MBC), antioxidant parameters (TOC, TAC, GSH, and CAT), and volatile component profile. According to the results, the titratable acidity of the vinegars were 5.92%–14.97% (w/v). The lactose amounts of KCW, KCWV, KCWV 5%, KCWV 10%, and KCWV 15% were determined as 32.912, 0.540, 0.615, 3.477, and 50.798 g/L, respectively and total protein amounts were determined as 0.948, 0.308, 0.423, 0.423, and 0.432 g/100 g, respectively. While KCW did not exhibit antibacterial activity against test bacteria, whey vinegars showed at different rates. KCWV exhibited a weaker antibacterial effect than the other whey vinegars. No TOC activity was found except for KCWV, and TAC was found at an average level in all samples. Additionally, ethanol and acetic acid were the dominant components in whey vinegars. The whey vinegar may be an important alternative to the valorization of whey which is a by-product of cheese production.