SHRINKAGE, DENSITY AND POROSITY OF GARLIC DURING DRYING

The apparent density of garlic cloves (with a moisture content range o f 10-65% wet basis) was evaluated by weighing the product in air and d etermining the corresponding buoyancy force in toluene. An analysis of variance (ANOVA) revealed a significant effect (P < 0.001) of moistur e on apparent density. The true density of dry garlic powder was inves tigated using density bottles. The data were fitted to the general den sity model for fruit and vegetables and to a second order polynomial e quation. Internal porosity varied during heated air drying in a non-li near (quadratic) form. Shrinkage during drying was measured by observi ng dimensional changes in garlic slabs (1.8 X 1.5 X 0.8 cm) dried in a convection oven, and a pilot cross-flow dryer, with drying air at 70- degrees-C and 14.5% relative humidity. Shrinkage was found to be fiber -oriented and different from the reported isotropic shrinkage of fruit s and vegetables.