Antioxidant capacity, total phenolic content and nutritional composition of Asian foods after thermal processing

Asian foods were studied for antioxidant capacity, total phenolics, and nutritional value. Varieties of commonly consumed foods were selected for the present study. They are chicken curry, spicy stir-fried pork, spicy sausage, curry dip, sate sauce (peanut sauce), and a dessert from black glutinous rice. The foods were packed in retort pouches and sterilized to understand the effect of heat on natural antioxidants to scavenge peroxyl radicals (ORAC assay) and DPPH radicals. One hundred grams of examined foods exhibited antioxidant capacity and total phenolic content ranging from 154.15 to 1499.63 μmole trolox equivalent from 7.46 to 40.16 mg vitamin C equivalent (VCE) and from 14.53 to 145.93 mg gallic acid equivalent, respectively. The top three highest foods in antioxidant capacity were Mu phat phrik khing (40.16 mgVCE/100g), Khua kling mu (31.38 mgVCE/100g) and Nam phrik ong (23.54 mgVCE/100g). The results showed that natural antioxidants retained their activity after thermal processing. Total phenolic content have a positive high correlation (r^2 = 0.90) with antioxidant capacity. The determined content of protein, fat, total dietary fiber and energy ranged 1.97-22.74, 2.28-24.97, 1.72-6.77 g/100 g and 125-342 Kcal/100 g, respectively.