Multi-radical (ORACMR5) antioxidant capacity of selected berries and effects of food processing

Abstract

BACKGROUND: Fruits and berries are known to contain relatively high amounts of antioxidant/bioactive compounds. Several methods have been used for measurement of antioxidant capacity (AC), but not all methods have direct relevance to in vivo antioxidant status. OBJECTIVE: Determine AC in berry/fruit samples, processed berry products, and purified compounds by utilizing 5 different biologically relevant free radical/oxidant sources. METHODS: Samples were assayed for AC capacity using 5 different free radical/oxidant sources: peroxyl radical (ORAC), hydroxyl radical (HORAC), peroxynitrite (NORAC), superoxide anion (SORAC) and singlet oxygen (SOAC)]. Total AC (sum of AC with 5 individual radicals) was expressed as Oxygen Radical Absorption Capacity using Multiple Radicals (ORACMR5). RESULTS: SOAC contributed more than 60 of ORACMR5 in blackberries, sweet and tart cherries; and no detectable levels of SOAC were found in strawberries, black currants and raspberries. Whole fruit purees of mango, wild blueberry and cherry contained 95, 85 and 67 respectively of total ORACMR5 from SOAC. However, freeze dried wild blueberry powder from same production season had only 28 as SOAC and 42 and 22 as ORAC and HORAC. Blueberry/Pomegranate and Mango/Pineapple smoothies had 67 and 77 of ORACMR5 as SOAC. CONCLUSIONS: The antioxidant quenching potential using 5 different radical/oxidant sources of different berries and fruits varied widely and understanding this variation may be helpful in understanding health benefits of different berries and foods.