Comparative Analysis of Phenolic Content and Antioxidant Capacities of Various Vinegar Types

In this study, the pH values, total phenolic content (TPC), total flavonoid content, and antioxidant capacities (using FRAP, DPPH, and CUPRAC assays) of different plant-based vinegar samples were evaluated. The highest phenolic content was detected in pomegranate vinegar (PV) with 754.53 µg GAE/mL extract, followed by blueberry (BV, 644.67 µg GAE/mL extract), apple honey (AHV, 436.61 µg GAE/mL extract), juniper (JV, 372.36 µg GAE/mL extract), grape (GV, 335.36 µg GAE/mL extract), and apple vinegar (AV, 279.46 µg GAE/mL extract), respectively. A similar trend was observed in flavonoid levels, with PV showing the highest value (512.23 µg QE/mL extract), followed by moderate levels in BV (159.42 µg QE/mL extract) and AHV (106.39 µg QE/mL extract), while AV had the lowest flavonoid content (3.57 µg QE/mL extract). Regarding antioxidant capacity, PV exhibited the highest activity in both FRAP (353.75 µg TE/mL extract) and CUPRAC (1326.70 µg TE/mL extract) assays. In the CUPRAC method, BV (709.70 µg TE/mL extract), JV (286.99 µg TE/mL extract), and AHV (284.70 µg TE/mL extract) followed PV; while in the FRAP assay, BV (241.80 µg TE/mL extract), GV (171.92 µg TE/mL extract), and JV (151.38 µg TE/mL) showed relatively high activities. In terms of DPPH radical scavenging activity, PV again demonstrated significantly high performance with a scavenging percentage of 44.78%. The findings indicate that pomegranate and blueberry vinegars stand out in terms of phenolic composition and antioxidant potential, while honey apple and juniper vinegars also present noteworthy levels of these bioactive properties. These results reveal the differences in phenolic content among vinegar types and demonstrate that those with higher phenolic levels are rich in bioactive compounds.