Hydrophilic and lipophilic antioxidant capacity of commonly consumed South African fruits, vegetables, grains, legumes, fats/oils and beverages

The antioxidant capacity of commonly consumed South African foods was determined using the fluorescein (FL)-based oxygen radical absorbance capacity (ORACFL) assay. The hydrophilic (H)-ORACFL of these foods ranged from 15 to 4202 μmole Trolox equivalents (TE)/100 g, and the lipophilic (L)-ORACFL from 11 to 109 μmole TE/100 g. The L-ORACFL of all the items analyzed contributed less than 5% of the total antioxidant capacity (TAC), except for sunflower oil (42%). Cultivar and seasonal availability influenced the H-ORACFL of some, but not all, fruits. The Golden Delicious apple cultivar has a lower (P < 0.05) H-ORACFL (with peel and peeled) compared to the other apple cultivars analyzed. Household thermal processing decreased the H-ORACFL of cabbage, brown onion and baby marrow (zucchini) (P < 0.05) and the L-ORACFL of potato and green beans (P < 0.05). Although the H-ORACFL of refined grains (e.g. maize porridge) is among the lowest, such foods make a substantial contribution to the daily dietary intake of the South African population.