Prediction of Dehydration Characteristics and Effective Moisture Content of Tarom Garlic Slices Undergoing Microwaveconvective Drying process

This study was undertaken to investigate the dehydration characteristics of the Tarom garlic in a microwaveconvective dryer. Drying of the garlic cloves was done using microwaveconvective technique, using microwave power of 100,180 and 300 W, air temperature of 40,100 and 140 o C and sample thickness of 5 and 7 mm and air velocity was held stable at 1 m. s - 1 . The effects of air temperature and a sample thickness on the dehydration characteristics were determined. Fick’s equation described the transport of water during dehydration. A third order polynomial relationship was found to correlate the effective moisture diffusivity ( ) eff D with moisture content. The ( ) eff D increased for the same values of dry air temperature as the applied microwave power was increased. The activation energy in the microwaveconvective drying was much lower than the convenctionally heating activation energy values. The obtained experimental dehydration data of garlic slices were fitted to the five semitheoretical drying models, i.e. Henderson and Pabis, twoterm, Lewis, Page, Verma et al., and a developed model by the researchers. Accuracy of the models were measured using the coefficient of determination ( R 2 ), root mean square error (RMSE) and sum of square error (SSE). All of the six models were acceptable for describing dehydration characteristics of garlic slices; however, based on statistical analysis, the developed model was the best one for prediction of dehydration characteristics of garlic slices.

کلیدواژه ها:

drying–microwave convection –garlic-diffusivity-modeling