EXPLORING THE ANTIOXIDANT ACTIVITY OF BLEEDING SAP FROM VARIOUS GRAPE VARIETIES

This investigation systematically evaluated the total phenolic content (TPC) and antioxidant properties of bleeding sap obtained from six grape cultivars—Evita, Cabernet Sauvignon, Prokupac, Smederevka, Muscat Hamburg, and Othello. The study employed quantitative assays to measure TPC, alongside three complementary methods (DPPH, ABTS, and CUPRAC) to determine the antioxidant capacity of the samples. The bleeding sap exhibited a wide range of phenolic concentrations, with TPC values spanning from 5.03 to 359.38 μg GAE/mL, suggesting significant variability among the cultivars. Antioxidant activity, as assessed by the DPPH assay, ranged between 83.68 and 96.29 μg TE/mL, while the ABTS and CUPRAC assays revealed activities from 13.07 to 37.48 μg TE/mL and 60.78 to 121.94 μg TE/mL, respectively. These findings underscore the potential of grape bleeding sap as a natural source of antioxidants and provide a scientific foundation for future studies aimed at exploring its application in food and pharmaceutical industries.