GRAIN SIZE AND HEAT SOURCE EFFECT ON THE DRYING PROFILE OF COCOA BEANS

Abstract

Four sweat boxes were constructed with wooden material (0.95 x 0.25 x 0.25m) L x W  x H and one electric  bulb with 100,200,300 and 400watts rating hoisted in each box interchangeably. Cocoa bean cleaned and sorted into four different grain   sizes samples (A, B, C, D) was subjected to drying till 13-14% moisture content was achieved. In another instance, 200g of the various sizes were also dried in oven, solar dryer and direct sun. During the drying, moisture loss was monitored, humidity and temperature of the drying were determined hourly and used to determine the drying profile of cocoa by response surface and regression analysis .The   moisture loss was significant among the cocoa sizes and ranged between 86.50g-114g for 400watts, and 49.9g in sample B at 100 watts. The least effective method was oven drying which recorded 13.17g moisture loss after 17 hours drying .The humidity was highest in the oven at 74.94% while the least was 61.94% on the solar drier. The sweat boxes with 400 and 300 watts were the most effective in terms of time-economy at 6 hours drying time. Sweat boxes can effectively be used to dry cocoa during heavy rains.