BIOACTIVE COMPOUNDS AND ANTIOXIDANT PROPERTIES OF SELECTED FRUITS AND VEGETABLES AVAILABLE IN THE VAAL REGION, SOUTH AFRICA

This study was conducted to assess the level of phytochemicals and antioxidant properties in a selection of fruits and vegetables available in the Vaal Region, and examine the effect of cooking. A wide distribution and variation in quantities of phytochemicals among the different samples was noted. The antioxidant capacity (mu mol Trolox-equivalent. 100/g fresh-weight) ranged from 178.5 (green bean) to 1814.4 (apple), and total phenolics (mg gallic acid-equivalent. 100/g fresh-weight) from 28.4 (apple) to 103.8 (carrot). Although significant levels of vitamin C (4.4-48.4 mg. 100/g fresh-weight) and Vitamin E (0.05-5.40 mg. 100/g fresh-weight) were recorded, polyphenols were the main provider of the antioxidant properties (r = 0.778; P < 0.001) followed by carotenoids, which showed significant correlation (r = 0.472; P = 0.020) with total antioxidant in vegetables. Cooking significantly affected (P < 0.05) the levels of phytochemicals; however, the pattern varied among the different vegetables and phytochemicals.