a study of the shrinkage changes and mathematical modeling of garlic (allium sativuml.) during convective drying

garlic (allium sativuml.) is one of the most important allium spice. from an economic point of view, the dried garlic slices are valuable products. in this research, garlic slices as a thin layer were dried in a laboratory scale hot-air dryer, under air flow of 1.5 m/s, air temperatures of 50, 60 and 70˚c and slice thicknesses of 2, 3 and 4 mm. the mean values of shrinkage of garlic slices obtained 69.8%. in addition, the effects of the drying variables on the shrinkage of dried garlic were evaluated. the anova results indicated that the air temperature and slice thickness had no significant effect on final shrinkage of dried garlic slices. in order to derive and select the appropriate shrinkage model, four mathematical models were fitted to the experimental data. according to the statistical criteria (r2, sse & rmse) the best model was found to describe the shrinkage behavior of garlic slice.