Nutritional, antinutritional and bioactivity of raw and thermal processed cultivars (five) of aerial yam bulbils

Abstract

The objectives of this research were to evaluate the effect of different cooking methods (boiling, steaming and roasting) on the nutritional, antinutritional, and antioxidative potential of five aerial yam cultivars. All the chemical analyses were carried out using standard analytical methods. Steamed (1.5–3.31 g/100 g and 0.18–2.19 g/100 g) and roasted (1.53–3.20 g/100 g and 0.23–2.51 g/100 g) samples showed higher retention of fructose and glucose, respectively. Cooking decreased antinutritional contents, especially oxalate in boiled aerial yam by 26.6% (Tob2857), 30.0% (Tob3059), 10.99% (Tob3086), 21.30% (Tob3694) and 25.27% (Tob3697). Also, steamed and roasted aerial yams declined by the range 9.52–60.77% (phytate), 5.44–68.36% % (alkaloid), 13.33–44.07% (tannin), and 17.53–68.35% (phenol), when compared to raw aerial yam. The DPPH activities increased significantly after all cooking processes. Roasted aerial yam had the highest (40.24–52.15%) DPPH activity, followed by boiled (33.86–51.65%) and steamed (29.13–45.42%) aerial yam. On the other hand, raw aerial yam had higher FRAP content than cooked aerial yam. Cooked aerial bulbils are reliable nutritional sources with high retention of fibre and DPPH and low sugar contents suitable for good health.