Experimental Study of Microwave Baking of Madeira Cake Batter

Microwave baking characteristics (surface and internal temperature, normalized height, moisture content) of Madeira cake were examined. Cake batter was baked in a bench-scale microwave oven (output power 100-900 W). As a control, an identical sample was baked in a convective oven at 200°C. Microwave baking allowed for up to a 93% reduction in baking time, in comparison with convective baking. The variation in sample centre temperature exhibited two distinct stages; a short 'warming-up' period, and a constant temperature (approximately 103°C) stage. A temperature profile through the cake depth revealed that the surface temperature to be lower than the centre. Normalized cake height was observed to increase and then slightly reduce towards the end of baking. A height profile across the sample cross-section revealed the maximum obtainable height was at the sample centre, with the maximum final sample height being achieved using 900 W. The experimental moisture data were adequately quantified in terms of drying constant and moisture diffusivity, both of which increased with power output. Cake baked in the microwave oven at 250 W showed improved textural properties (springiness, moisture content, firmness) as compared to cake baked in the convective oven.