Effects of cooking methods on physicochemical properties, antioxidant
properties and sensory acceptability of purple sweet potato (Ipomoea batatas)

Purple sweet potato is commonly cooked by boiling, steaming, baking and microwaving.
However, information on the effects of cooking methods on the physicochemical
properties, antioxidants properties and sensory acceptability is limited. In this study, the
effect of cooking methods (boiling, steaming, baking and microwaving) on the
physicochemical properties, antioxidant properties and sensory acceptability of purple
sweet potato were investigated. The results showed that the boiled sample was the softest
(hardness of 933.39 g) and also had the highest total colour difference (18.56), while the
steamed sample was the most adhesive (-92.35 g.s) and least cohesive (0.41). An
increased moisture content caused a decrease in other proximate compositions in the
samples. The baked sample had the highest antioxidant properties, with 232.20 mg
GAE/100 g of total phenolic content, 2.05 mg cyaniding-3-glucoside/L of total
anthocyanins, 61.95% of DPPH and 79.20% of ABTS radical-scavenging activity. The
steamed sample was rated most acceptable by the panellists.