A Comparative Assessment of alpha-Tocopherol Content and Antioxidant Activity of Some Fresh and Commercial Fruit Juices

Aim: Fruits and vegetables are the main sources of antioxidant compounds and vitamins. In nature, alpha-tocopherol, is the most abundant and biologically active form of Vitamin E. The current study was aimed to investigate the antioxidant activity and alpha-tocopherol content of commercial and freshly squeezed fruit juices. Material and Methods: Apple, apricot and tomatoes fresh and commercial fruit juices were evaluated for their potential antioxidant activities using DPPH and ABTS(+) radical scavenging capacity assays. The total phenolic and flavonoid content of juices were determined by Folin-Ciocalteu and Aluminium chloride colorimetric methods respectively. The alpha-tocopherol contents of juices were investigated by HPLC-UV chromatographic method. Results: The highest alpha-tocopherol concentration was found in freshly squeezed tomatoes juice (0.0761+0.20mg/100g) the total phenolic content of freshly squeezed fruit juices measured by Folin-Ciocalteu assay, ranged between 2.10-12.83mg gallic acid equivalents (mg GAE/100ml). The total flavonoid content of samples was expressed as quercetin equivalents (mg QE/100ml). The commercial tomatoes juice showed higher content of flavonoid (4.10 +/- 0.0126 mg QE/100ml), followed by freshly squeezed apple and apricot fruit juices. The fresh fruit juices of tomatoes showed the lowest content of flavonoid and highest content of total phenolic compounds. Freshly squeezed apple juice and apricot juice were found to exert higher antioxidant activities in ABTS(+) and DPPH assays respectively. Conclusion: It was observed that alpha-tocopherol content and antioxidant capacities and total phenolic and flavonoid concentrations of freshly squeezed juices were higher than commercial ones.