Shrinkage characteristics of potatoes dehydrated under combined microwave and convective air conditions

A study of the physical structure and quality of potatoes during microwave and air drying was undertaken. The effect of various experimental variables on volumetric shrinkage including microwave power levels, air temperature and velocity as well as sample geometry was investigated In both microwave and air drying, the shrinkage of potatoes showed a linear behaviour in relation to different moisture content levels. Experimental data showed that air velocity and microwave power had a major effect on the degree of shrinkage, also, the shrinkage behaviour was independent of sample geometry and air temperature The use of microwaves produced smaller changes in volume ( less shrinkage) and hence a better quality finished product.