SHRINKAGE, DENSITY AND POROSITY OF GARLIC DURING DRYING

The apparent density of garlic cloves (with a moisture content range of 10-65% wet basis) was evaluated by weighing the product in air and determining the corresponding buoyancy force in toluene. An analysis of variance (ANOVA) revealed a significant effect (P < 0.001) of moisture on apparent density. The true density of dry garlic powder was investigated using density bottles. The data were fitted to the general density model for fruit and vegetables and to a second order polynomial equation. Internal porosity varied during heated air drying in a non-linear (quadratic) form. Shrinkage during drying was measured by observing 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 fruits and vegetables.