Abstract

Drying experiments were carried out to investigate the effect of forced-air, artificial intermittent drying system on quality of fermented cocoa beans harvested in south-western Nigeria. The beans were dried naturally by using traditional sun drying method and artificially, by hot air inside an oven at air temperatures of 35, 40, 45, 50 and 55°C respectively. Fermented beans were exposed to 9 h of drying and 15 h of resting daily. The following quality parameters were assessed; free fatty acid (FFA), pH, moisture content and acetic acid for each drying temperatures and sun drying. From the test results, the free fatty acid and acetic acid levels increases with increase in drying temperature, also, the pH level decreases with increase in drying temperature. Optimum bean-quality was obtained for cocoa beans dried at 45°C oven temperature. A predictive equation was established that shows the relationship between oven temperature (°C) and free fatty acid level (mg/g) of the beans. Generally, it was also discovered that there is no known adverse effect on the quality of the beans dried under forced-air artificial intermittent drying system.

Key words: Effect, temperature, cocoa beans, forced-air, artificial, intermittent, free fatty acid, acetic acid quality, convection.