Compressive Properties of Cocoa Beans Considering the Effect of Moisture Content Variations

摘要

The compressive properties of premium quality cocoa beans from Ghana considering the effect of moisture content in the moisture range of 7% to 22 % (w.b) were studied. The results of the study demonstrated that the displacement at maximum load or the deformation and the crushing energy had more positive linear function with moisture content and increased significantly from 0.80 mm to 1.87 mm and from 13.0 mJ to 200 mJ respectively. The compressive strain and Young’s Modulus decreased significantly in linear relationship with very high correlation coefficient within the confines of the moisture content, which increased from 0.009 to 0.0045 mm/mm, and 1300 MPa to 205 MPa respectively. The compressive stress however decreased exponentially with increasing moisture content from 1.5 MPa to 0.3 MPa. The increase in deformation and subsequent decrease in compressive stress and strain of the cocoa bean, as the moisture content increased, shows that the energy absorption capability of wet cocoa bean is higher than the dry ones leading to higher mechanical strength to rupture during the lateral compressive loading. These findings provide useful information for food and agricultural engineers in the design of suitable cocoa beans crackers.