Application and Comparison of Methods of Antioxidant Activity Determination in Fruit and Vegetable Juices

Abstract

Antioxidant activity of 18 fruit and vegetable juices was determined using DPPH (2,2-diphenyl-1-picryl­hydrazyl), FRAP (ferric reducing antioxidant potential), PCL (photochemiluminiscence) methods. Correlations between the results of individual methods and the total phenolics and anthocyanin contents were evaluated. Water and methanol extracts were applied in the determinations. In both water and methanol extracts, a significant correlation between the results of all the three methods was found. However, the correlation between the results of PCL and total phenolics content is poor. No correlation between the results of ACW and ACL was found. Antioxidant activity in the tested juices decreased in the order: blueberry > red cabbage > raspberry > sour cherry > strawberry > beetroot. Celery, carrot and cucumber are poor sources of antioxidants. The orders found by various methods do not differ significantly; DPPH, FRAP and ACL methods are interchangeable for this purpose. For complete information on antioxidant activity, application of more methods following different effects is necessary.