Transport and related properties of breads baked using various heating modes

Physical properties of breads during baking were measured using three different heating modes of microwave plus infrared (MIR), microwave plus jet impingement (MJET) and jet impingement (JET) in two different commercially available microwave combination ovens. Breads baked in JET oven were significantly different from the breads baked in other ovens with respect to their specific volume and moisture content. Transient values of dielectric constant, dielectric loss factor, specific bulk volume, porosity, thermal conductivity and moisture content were determined. For all heating modes, thermal conductivity and dielectric properties of breads decreased sharply within the first 2–3 min of baking and then remained constant. Regression equations were developed to relate these properties to moisture content and porosity changes during baking.