study of physical properties, phenolics compounds and antioxidant activity of thirty different iranian cultivars of pomegranates peels

pomegranate (punica granatum l.) is an important iranian-native fruit, whose many varieties are cultivated. fruits are widely consumed fresh and in processed forms as juice, jams and etc. pomegranate peel, as a by-product of the commercial juice industry, is a rich source of bioactive compounds. this research has been done to evaluate and compare physical characteristics, total phenolics, total tannins and antioxidant activity of thirty different cultivars of pomegranates peels in a completely randomized design with 4 replications. this study showed that there were significant differences among the cultivars in all measured factors. the fruit weight, peel percentage and peel thickness were within the range of 196.89-135.87 g, 59.82-63.61% and 3.13-5.25 mm, respectively. the results also showed that the values of total phenolics ranged from 320.35 mg g-1 dry matter to 328.52 mg g-1 dry matter. the total tannins content was observed in pomegranate cultivars between 189.35 mg g-1 dry matter and 197.35 mg g-1 dry matter. the antioxidant activity of pomegranate peel, as determined by the dpph assays, was between 69.60 and 93.60%. in addition, the antioxidant activity was positively correlated with the total phenolics (r = 0.923) and total tannins (r = 0.816). these results demonstrated that the cultivar is the main parameter which determined the physical properties, phenolics compounds and antioxidant activity in the peel of pomegranate. the large amount of phenolics compounds in pomegranate peels provided a good potential as a supplement rich in natural antioxidants.