Phytochemical profile and antioxidant properties of vinegars obtained from naturally grown berry fruits in the Black Sea region

Fruit vinegar samples obtained from six different fruits (hawthorn, strawberry, mulberry, kiwi, grape, and rosehip) were evaluated in terms of total phenolic and flavonoid contents, antioxidant activity (DPPH assay), and selected phenolic and organic acid profiles. The highest total phenolic and flavonoid contents were observed in kiwi vinegar, measuring 676 mg GAE L⁻¹ and 694 mg QE L⁻¹, respectively. Regarding DPPH antioxidant activity, the highest values were recorded for kiwi, strawberry, and mulberry fruit vinegars (93%, 92%, and 92%, respectively). Among phenolic acids, mulberry fruit vinegar was rich in protocatechuic acid, rosehip fruit vinegar contained high levels of gentisic acid, and ellagic acid was abundant in both grape and kiwi fruit vinegars. Concerning organic acids, rosehip fruit vinegar exhibited remarkable levels of acetic and tartaric acids. These results demonstrate significant biochemical differences among the studied fruit vinegars and highlight kiwi, strawberry, and rosehip fruit vinegars as particularly valuable sources of phenolic and flavonoid compounds and antioxidant activity.