Investigation of phenolic compounds and antioxidant capacity in leaves, unripe, ripe, sundried and molasses of red raisin grape

Grape contains various nutrients, including vitamins, minerals, carbohydrates, organic and phenolic acids. The aim of the present study was to determine and compare total phenolic and flavonoieds compounds and antioxidant activity in different part (leaves, unripe, ripe, sun dried and molasses) of red raisin grape variety. Red raisin grape variety was collected from Keshtiban village in the Urmia city. The extraction of leaves, unripe, ripe, sun dried and molasses fruit was carried out by using methanol solvent. The total antioxidant activity, total phenolic and total flavonoid content from the different parts of red raisin cultivar of grape were compared. The total phenolic and flavonoid content were determined using spectrophotometry method. Antioxidant capacity of extracts was determined using DPPH, super oxide and nitric oxide methods. Reduction capacity of extracts was measured with FRAP assay and ability to inhibit lipid peroxidation by using TBA method. The results showed the leaves extracts of red raisin grape have the most content of phenol, flavonoid and antioxidant activity. The highest percent of DPPH, super
oxide, nitric oxide radicals scavenging and lipid peroxidation were obtained in leaves. The results showed sun dried fruit of red raisin grape had higher antioxidant activities and compounds than unripe and ripe fruit. Different parts of grape are a rich source of natural antioxidant. Therefore, it is observed that total parts of grape can be used as a natural antioxidant for use by consumers and the food industry in development of new products.