ANTIOXIDANT ACTIVITY AND TOTAL PHENOLIC CONTENT OF GRAPE SEEDS AND PEELS FROM ROMANIAN VARIETIES

Abstract

Grape seeds and peels are valuable by-products from wine production industry that can be valorized in food production. Both grape seeds and peels have a great amount of antioxidants and polyphenolic compounds. The aim of this study was to investigate the total phenolic content of red and white grape seeds and peels and to establish the optimal solvent concentration for highest extraction yield. For this purpose, Folin Ciocâlteu method was used to achieve the phenols content and the antioxidant activity was estimated using 2,2 – diphenyl-1-1picrylhydrazyl (DPPH) reagent. The total phenolic content ranged from 81.13 mg GAE/g for red peels, 93.47 mg GAE/g for white peels, to 128.47 mg GAE/g for red seeds and 164.70 mg GAE/g for white seeds. The One-Way ANOVA method was used to see if there are differences between the antioxidant activities depending on the solvent concentration. The results showed that the methanol concentration significantly (p < 0.05) influences the antioxidants extraction. The inhibition percent IC₅₀ ranged from 0,24 to 4,37 μg/mL for white peels, from 3,12 to 6,29 μg/mL for red peels, from 5,53 to 5,90 μg/mL for white seeds and from 4,59 to 6,14 μg/mL for red seeds. This study highlighted the possibility to use grape seeds and peels as food ingredients or natural antioxidant to extend the shelf life of food, especial of lipids and lipid-containing foods because of their high antioxidant activity and total phenolic content.