Investigation of Polyphenolic Compounds and Antioxidant Properties of black peel Pomegranate Juice cultivar (Punica granatum) in Saveh

Abstract   Background and Objectives: black peel pomegranate is one of the indigenous cultivars in Iran, which is approximately rare in comparison with other cultivars and is used as an herbal therapy.  In this research, the aim was study of polyphenol compounds and antioxidant activity of pomegranate juice, condensed juice with freeze dryer, and vacuum oven and the choice of the best pomegranate juice condensation method.   Materials and Methods: For this purpose, pomegranate fruits were washed, squeezed for obtaining the juice, and after the juice was condensed by two methods, freeze dryer and vacuum oven, then antioxidant activity using DPPH assay, total phenol using Folin-Ciocalteu reagent, flavonoids using aluminum chloride method, and detection and quantity of polyphenol compounds using HPLC in the samples were determined.   Result: Results showed that the highest polyphenol compound of the condensed black peel pomegranate juice was punicalagin B. In addition, the highest antioxidant activity (70.0±0.40%), total phenol (2517.0±0.75 mgGa/100ml), and flavonoid (390.50±0.00 mgQ/100ml) were belonged to the condensed pomegranate juice with freeze dryer in comparison with natural pomegranate juice and condensed pomegranate juice with vacuum oven, respectively. The results showed that there are the significant differences in the amounts of antioxidant activity, polyphenol compounds, total flavonoid, and total phenol of the condensed pomegranate juices and natural pomegranate juice (p<0.05).   Conclusion: The condensed black peel pomegranate juice with freeze dryer had the highest polyphenol compounds and antioxidant activity values in comparison with the pomegranate juice with vacuum oven. Therefore, the condensation of pomegranate juice using freeze dryer because of preserving of polyphenol compounds and their antioxidant activities are proposed for its application in food industry.