The physical properties of Category B cocoa beans Original Research Article

Physical properties of Category B cocoa beans from the 2000/2001 harvesting season were determined as a function of bean moisture content in the moisture range between 5% and 24% (wb). In the above moisture range, the mean bean length, width and thickness increased from 22.41 to 22.5 mm, 12.2 to 12.86 mm and 7.36 to 7.70 mm respectively. At the moisture content of 8.6% (wb), 87% of the beans had lengths between 20.0 and 26.0 mm, 87% had their width between 10.0 and 14.0 mm and 95% had their thickness between 6.0 and 10.0 mm. The sphericity varied from 0.57 at 8.6% (wb) moisture content to 0.58 at 24.0% (wb) moisture content. The mean bean mass ranged between 1.11 and 1.31 g with 77% of the beans ranging between 1.13 and 1.53 g at 8.6% (wb). The 1000-bean mass and the percentage shell mass increased from 1125 to 1247 g and from 10.7% to 19.6% respectively. The particle density and porosity increased from 946 to 991 kg/m3 and 20.58 to 31.59% respectively while the bulk density decreased from 560 to 505 kg/m3. The filling and emptying angles of repose increased with increase in moisture content from 23.7° to 33.8° and 27.3° to 37.5° respectively. The coefficient of static friction of the beans increased from 0.20 to 0.25, 0.45 to 0.60 and 0.53 to 0.7 for rubber, galvanised steel and plywood respectively.