Assessment of greenhouse technologies on the drying behavior of cocoa beans

Cocoa beans (Theobroma cacao L.) are the principal raw material for chocolate manufacture. Before cocoa beans are ready for the chocolate industry, farm-based fermentation and drying processes are key determinants of bean quality and hence the price. To improve its value, cocoa beans were dried in a modified greenhouse (MGHD), conventional greenhouse (CGHD), and open sun (OSD) dryers. The drying behavior, kinetics, and quality were evaluated. The MGHD was constructed by modifying a conventional greenhouse with a fleece of black polyester material. Evaluation of air properties of the dryers without and with cocoa beans showed that the MGHD had average temperatures of 2 and 8°C above, and relative humidity of 12.28% and 25.48% below the CGHD and OSD, respectively. The drying data were fitted to four thin layer mathematical models. The Page and Overhult models gave favorable ranges of R2 (.976 to .987), chi-square (3.7 × 10-4 to 9.9 × 10-4), and root mean square (RMSE; 0.0188 to 0.0307) for the three dryers. The cocoa beans dried in the MGHD took a shorter time to reach the expected 5%-8% moisture content and were of grade one quality.