SUMMARY
The main purpose of drying foodis increase the shelf life of the final product.There are different methods of drying food.Each of these methods hastheir own advantages and applications.Increasing concerns about product quality and production costshas interested researchers to examine the use of microwave technology for drying.Drying by microwave is a quick dewatering technique.Short processing time in drying by microwave, improve product quality and flexibility in the production of a wide range of dried products are as the advantages of microwave drying, especially for putrefying products.In this study the possibility of using the microwave oven for drying aloe vera and effective drying parameters were evaluated.Experiments were done in three powers (0.25, 0.50 and 0.75 watts) and in the range 2 to 50 minutes. In these studycurves of drying by kinetic mathematical models of Henderson and Pabys, binomial, Wong and Singh, Henderson and "reformed Pabys" and February, which are widely used for biological substances and the majority of food items, was fitted.To determine the most appropriate mathematical model to describe the behavior of drying, fitness of 5 mathematical models by determining the determination coefficient and the total mean square error (MSE) was evaluated.In this method, firstly a mathematical intended model is selected, then based on the amount of moisture absorption and equilibrium model relationship an objective function was define to optimizationand after optimization, optimizedconstants of mathematical model was obtained intended as functions of operating parameters.The results of the fitnessof models showed that the mathematical model of Henderson and "Pabysmodified " and binomial were highly adapted to the laboratory data.