Determination of vitamin C and total phenolic in fresh and freeze dried blueberries and the antioxidant capacity of their extracts

Berries are often tagged ‘super fruits’ and command premium prices due to their purported high concentration of antioxidants and vitamin C. This study sets out to support or dispute the above assertion through a comparative analysis of the total phenolic and vitamin C in cultivated fresh (variety; Draper, Duke and Brigatta) and freeze dried blueberry coupled with the determination of the antioxidant capacity of their extracts. DCPIP, Folin-Ciocalteu and DPPH assays were used. The total phenolic content ranged from 262.64 to 287.96 mgGAE/100 gms in the fresh berries and was 426.06 mgGAE/100 gms in the freeze dried samples. The amount phenolic content of the freeze dried blueberries is significantly higher than in the fresh blueberries. Thus the apparent antioxidant health benefit of the freeze dried berries outweighs that of the fresh berries. The fresh samples had an average measurement of 10.9 mg/100 gms of vitamin C with a small variance and the total antioxidant activity ranged from 28% to 49%.