Effects of different cooking methods on bioactive compound content and antioxidant activity of water spinach (Ipomoea aquatica)

Abstract

Water spinach (Ipomoea aquatica) is a green leafy vegetable commonly found in Vietnam and other tropical countries. We identified the best extraction solvent and compared the effects of different cooking methods on phytochemical contents and antioxidant activity of water spinach. Steamed water spinach extracted with 80% ethanol had the highest amounts of 35.0 mg/g total chlorophylls, 7.1 mg/g carotenoids, 35.6 mg/g total polyphenols, and 40.4 mg/g total flavonoids. The steaming process showed higher antioxidant activity than the uncooking or boiling process. The 80% ethanol extract showed a higher level of antioxidant activities than the water extract. The antioxidant activity was measured with the DPPH, ABTS, hydroxyl and superoxide anion racial scavenging assays as well as the reducing power activity assay were increased in a concentration dependent manner. The overall results support that water spinach contains bioactive compounds and they may play a positive role in our health.