Effect of steaming, boiling and microwave cooking on the total phenolics, flavonoids and antioxidant properties of different vegetables of Assam, India

All the fourteen vegetables selected for the study are an integral part of the diet in North Eastern India. Vegetables like banana blossom, roselle leaves, black eyed pea and teasle gourd are traditionally known to be good for health. The present study determined the effect of three cooking treatments viz. steaming, conventional boiling and microwave cooking on the phytochemical contents (TPC, TFC) and antioxidant activitites (FRAP, DPPH, MCC) on the fourteen vegetables. Results showed both positive and negative impact on the phytochemical properties of the vegetables depending on the cooking method employed and type of the vegetable. Among the three cooking methods employed, steaming emerged as the most suitable method followed by microwave cooking in most of the cases in terms of retention of phytochemicals and antioxidant activities.