Effects of Steaming and Microwave Cooking on Quality Attributes of Selected Green Vegetables

Cooking at high temperature and longer time leads to degradation of physical and nutritional properties of vegetables. The aim of the study was to evaluate the effects of steaming and microwave cooking on total phenolic, chlorophyll, antioxidant activity and colour of spinach (Spinacia oleracea), mustard green (Brassica juncea) and water spinach (Ipomoea aquatica). Prolong cooking time of both steaming and microwaving increased the amount of total phenolic content, antioxidant activity but decreased the chlorophyll content of the green vegetables tested. The colour, L* value decreased indicating darker hue while greenness (-a*) and yellowness (+b*) increased as the time of cooking increased. Cooking using microwave caused greater destruction in quality of vegetables compared to steaming.