EVALUATION OF THE DRYING PARAMETERS OF COCOA HUSKS

Abstract

Cocoa pod husk causes environmental pollution problems in the cocoa producing areas of the world. They serve as potential sources of disease transmission in cocoa farms when it is not properly handled. This study evaluated the drying characteristics of cocoa pod husk as affected by the pod size and drying temperature and the effect of drying system on the proximate, minerals and phytochemical composition of the cocoapod husk. The drying experiment was carried out on fresh cocoa pod husk sliced into three different sizes (1/2, 1/4 and 1/8 pod sizes) and dried in three different drying systems thus, cabinet dryer (at 50°C, 60°C, 70°C, 80°C and 90°C drying air temperature), solar dryer and open sun drying. The change in moisture content of the cocoa pod husk was monitored at regular intervals of 30min until the moisture content of the sample became constant. The result shows that the drying rates were higher for the highest temperature (90oC) used in this study and decreases with the decrease in dry air temperatures. Also, the cabinet drying was found to be more effective for moisture removal compared to other drying methods (solar and open sun drying). However, moisture diffusivity values of the cocoa pod shows declining trend with decrease in the pod sizes and increase in drying air temperature and ranged between5.814 × 10-10 and 24.852 × 10-10 m2/s with activation energy ranging between 25.12 and 31.85kJ/mol. The Midili kucuk (0.989 ≤ R2 ≤ 0.998) and Hii et al (0.983 ≤ R2 ≤ 0.996,) models were selected as the best model for predicting the drying characteristics of cocoa pod. Ash content of the dried sample for open sun was (11.06 ± 0.679%), solar dryer (8.175 ± 0.474%), and cabinet dryer (10.854 ± 0.038%) with crude protein and fiber content for the fresh sample of cocoa pod husk was significantly (p<0.05) higher and lower respectively when compared to dried samples. The sample dried in cabinet dryer has the highest Fe (6.5 ± 0.141 mg/100g), Mg (66 ± 1.414 mg/100g) and Na (1.24 ± 1.414 mg/100g) values compared to the value gotten from open sun drying and solar drying system that are not to significantly different from one another and the phytochemical composition of cocoa pod husk might not significantly destroyed by heat only also the time spent in the system.