|Assuming microwave ovens cook on the principle of "moist" heat cookery, what are the general effects of microwave cooking on various foods, including effects on chemical structure? — EJ, Sydney, Australia
Microwave ovens cook by depositing thermal energy in the water molecules, which isn't the same as cooking food in moist hot air. Microwave cooking tends to heat food uniformly throughout where as more conventional "moist" heat cooking still heats food from the outside in. Nonetheless, the chemical effects on food are very similar for both types of cooking. Virtually all of these effects are caused by elevating the temperatures of the food. I'm not an expert on the chemistry of cooking, but elevated temperatures certainly denature proteins and caramelize sugars.