Different cultivars of four Vaccinium species [Vaccinium corymbosum L (Highbush), Vaccinium ashei Reade (Rabbiteye), Vaccinium angustifolium (Lowbush), and Vaccinium myrtillus L (Bilberry)] were analyzed for total phenolics, total anthocyanins, and antioxidant capacity (oxygen radical absorbance capacity, ORAC). The total antioxidant capacity of different berries studied ranged from a low of 13.9 to 45.9 μmol Trolox equivalents (TE)/g of fresh berry (63.2−282.3 μmol TE/g of dry matter) in different species and cultivars of Vaccinium. Brightwell and Tifblue cultivars of rabbiteye blueberries were harvested at 2 times, 49 days apart. Increased maturity at harvest increased the ORAC, the anthocyanin, and the total phenolic content. The growing location (Oregon vs Michigan vs New Jersey) did not affect ORAC, anthocyanin or total phenolic content of the cv. Jersey of highbush blueberries. A linear relationship existed between ORAC and anthocyanin (r xy = 0.77) or total phenolic (r xy = 0.92) content. In general, blueberries are one of the richest sources of antioxidant phytonutrients of the fresh fruits and vegetables we have studied. Keywords: Vitamin C; ascorbate; blueberry; bilberry; highbush; lowbush; rabbiteye; ORAC; HPLC

Fresh strawberries (Fragaria x ananassa Duch.), raspberries (Rubus idaeus Michx.), highbush blueberries (Vaccinium corymbosum L.), and lowbush blueberries (Vaccinium angustifolium Aiton) were stored at 0, 10, 20, and 30 degrees C for up to 8 days to determine the effects of storage temperature on whole fruit antioxidant capacity (as measured by the oxygen radical absorbing capacity assay, Cao et al., Clin. Chem. 1995, 41, 1738-1744) and total phenolic, anthocyanin, and ascorbate content. The four fruit varied markedly in their total antioxidant capacity, and antioxidant capacity was strongly correlated with the content of total phenolics (0.83) and anthocyanins (0.90). The antioxidant capacity of the two blueberry species was about 3-fold higher than either strawberries or raspberries. However, there was an increase in the antioxidant capacity of strawberries and raspberries during storage at temperatures >0 degrees C, which was accompanied by increases in anthocyanins in strawberries and increases in anthocyanins and total phenolics in raspberries. Ascorbate content differed more than 5-fold among the four fruit species; on average, strawberries and raspberries had almost 4-times more ascorbate than highbush and lowbush blueberries. There were no ascorbate losses in strawberries or highbush blueberries during 8 days of storage at the various temperatures, but there were losses in the other two fruit species. Ascorbate made only a small contribution (0.4-9.4%) to the total antioxidant capacity of the fruit. The increase observed in antioxidant capacity through postharvest phenolic synthesis and metabolism suggested that commercially feasible technologies may be developed to enhance the health functionality of small fruit crops.