Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Abstract:
This research focused on modeling the effects of dryer parameters on drying kinetics of onion slices. Onion slices were dried in a convective electric dryer. The treatments in the experiment comprise of two levels of onion slice thickness (3mm and 4mm); and three levels of drying temperature (45, 50 and 600C). The data obtained from the drying experiment was fitted to seven thin layer drying models from literature. Results of the drying experiment revealed that drying rate of the onion slices increased with increase in drying air temperature and reduced with increase in slice thickness of the onion slices. It was also observed that the drying rate was highest at the beginning of the experiment, but reduced significantly towards the end of the experiment. The highest drying rate of 12.25%/hr was obtained for onion slices dried at temperature of 600C and thickness of 3mm; while the lowest drying rate of 6.23%/hr was obtained for onion slices dried at temperature of 450C and slice thickness of 4mm. The modified Aghbashlo model gave the best fit to the drying data with coefficient of determination (R2) of 0.9999, root mean squared error (RMSE) of 0.0027, and sum of squared error (SSE) of 0.000022. It was therefore chosen as the best fitted model for thin layer drying of onion slices. Generally, the modeling of drying kinetics of onion slices, would improve the drying process of onion bulbs, thereby solving the problems of onion wastage during the harvesting period.

Keywords: Convective Dryer, Treatments, Drying Rate, Temperature, Slice Thickness, Coefficient of Determination,

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