Consumers who want fresh microwaved foods that are supposed to be crisp and taste better can look forward to improvement, thanks to new Cornell University studies that show how moisture, heating rate and the food's porosity interact during microwave cooking. Up to now, as scientists, we haven't really understood much of the physics which occur during the microwave processing of food. This research shows us the quantitative physics as to why microwaved food can be soggy and sometimes unappealing, and also why sometimes excessive amount of moisture can be lost. In conventional ovens, foods such as baked potatoes are heated from an external source, the hot air, and heated from the outside in. Researchers know that the surfaces of conventionally baked foods are generally hotter than the inside and that moisture escaping from conventionally cooked foods is whisked away by heat as it reaches the surface.
Internal pressure causes a lot more moisture to reach the surface.
This accounts for apparent sogginess, Datta said. With time, the surface of microwaved food has more moisture than inside the food, reverse of that for heating in conventional ovens. Taking food porosity into account, microwave food processors and other food companies can design foods for more desirable quality.