Diversity evaluation of biochemical parameters and antioxidant activity in some commercial grape cultivars

Iran is the origin center of grape and a large number of commercial grape cultivars are grown with different biochemical properties. In order to study and compare the biochemical attributes and antioxidant activity of some grape cultivars, 7 grape cultivars including Bidane Sefid, Bidane Ghermez, Tabarze Sefid, Tabarze Ghermez, Ghezel Ozum, Lale Ghermez and Rish Baba were prepared from a uniform grape garden in Urmia city. Soluble solids content, titratable acidity, TSS/TA, vitamin C, total phenolics content, polyphenol oxidase enzyme activity, antioxidant activity and fruit juice were evaluated. The results showed a significant difference between the studied cultivars for all measured traits. The highest soluble solids content and organic acids were found in Bidane Ghermez cultivar. The highest TSS/TA and vitamin C values ​​were recorded in "Rish Baba". Also, the highest phenolics content and polyphenol oxidase activity were observed in Tabarze Ghermez and Lale Ghermez cultivars respectively.  Total antioxidant activity varied from 255.9 (mmol Fe 2+ per 100 g fresh weight) in Tabarze Ghermez cultivar to 294.3 (mmol Fe 2+ per 100 g fresh weight) in Bidane Sefid.