Comparative Analysis of Ascorbic Acid Content and Antioxidant Activity of Some Fruit Juices in Syria

Fruits are considered essential constituents of a healthy diet. They possess antioxidant properties which can be attributed to the presence of antioxidant compounds. Ascorbic Acid (AA) is a water soluble antioxidant, abundant in fresh fruits and juices and considered as one of the most important contributors to the total antioxidant activity of fruits and vegetables. Two samples of the following fruit juices (orange, grapefruit, black mulberry, strawberry, pomegranate and tomato) were investigated for their AA content and total antioxidant activity. AA content was determined according to dichlorophenol indophenol method. Orange juice showed the highest results with amounts from 74.85mg/100 ml to 101.28mg/100 ml, while the lowest was pomegranate juice with amounts from 8.6mg/100 ml to 8.8mg/100 ml. Total antioxidant activity was subsequently determined using Ferric Reducing Antioxidant Power (FRAP) assay and reducing power assay. The results indicated that black mulberry juice had the highest antioxidant power, while tomato juice had the lowest. The study concluded that AA plays a dominant role as an antioxidant only in fruit juices which are known to be rich in AA. Other juices showed higher antioxidant activity which indicated the role of other antioxidant compounds i.e. phenolic compounds.