The thin layer drying kinetics of chilli is experimentally investigated in hot air oven and fluidized bed dryers.\r\nExperiments were conducted at inlet air temperatures of 45??, 50??, 55??, 60?? and 65??. The power consumption and quality\r\nparameters (color and capsaicin content) were measured in each experiment. Thirteen different thin layer mathematical drying\r\nmodels were compared by using their regression coefficient, chi square value and RMSE (root mean square error). The Midilli\r\nmodel was found to be the best mathematical model which could use to satisfactorily predict the moisture ratio of chilli at\r\ndifferent drying air temperatures in each type of dryers used. Surface colour chromaticity parameter a* changed from 32.5 at\r\n45?? to 25.8 at 65?? temperature in hot air dryer whereas it was changed from 29.3 at 45?? to 23.8 at 65??. When temperature\r\nincreases from 50?? to 65??, there is a considerable reduction in the colour of chilli in both dryers. Capsaicin concentration was\r\ninversely related with the air temperature and there was a sharp reduction of capsaicin concentration when increasing the\r\ntemperature from 60?? to 65??. The energy consumption was higher in fluidized bed dryer than the hot air oven dryer when\r\nmoisture content of chilli reduced from 280% to 9% (d.b) during drying process. The retention time of the fluidized bed dryer in\r\nall operating temperatures was nearly three times less that of hot-air oven dryer due to higher air flow characteristics. Lowest\r\npower consumption occurred at 65?? temperature setting in both dryers while the fluidized bed dryer consumed nearly 75% more\r\npower.
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