Moisture transport in intensive microwave heating of biomaterials: a multiphase porous media model

A multiphase porous media model was developed to predict moisture transport during intensive microwave heating of biomaterials. Internal pressure grad ients arise from internal heating and vaporization and significantly enhanc e the transport. Even a moderate internal pressure gradient in a low moistu re material can cause more moisture to move to the surface than can be remo ved from the surface, leading to a soggy surface. A strong internal pressur e gradient in a high moisture material can fully saturate the surface, lead ing to a very high moisture loss by liquid outflow at the surface. Addition of hot air and/or infrared heating of the surface to increase evaporation is suggested as a way to reduce surface moisture build-up. (C) 1998 Elsevie r Science Ltd. All rights reserved.