Effect of moisture, bulk density and temperature on thermal conductivity of ground cocoa beans and ground sheanut kernels

Abstract

Thermal conductivity is an important engineering parameter in the design of food processing equipment. It predicts or controls the heat flux in food during processing such as cooking, frying, freezing, sterilization, drying or pasteurization. The thermal conductivity of ground cocoa beans and ground sheanut kernels with varying moisture content, bulk density and temperature was studied using the transient heat transfer method. The thermal conductivity increased linearly for ground cocoa beans sample from 0.0243 to 0.0311 W/oCm and for ground sheanut kernels from 0.0165 to 0.0458 W/oCm in the moisture content range of 12.59 to 43.84 % w.b. at a constant bulk density of 295 kg/m3. For bulk density range of 322 to 410 kg/m3, thermal conductivity of ground cocoa beans and ground sheanut kernel increased linearly from 0.0265 to 0.0324 W/oCm and 0.0209 to 0.0252 W/oCm respectively when moisture content was at 16 % w.b Thermal conductivity of ground sheanut kernel and ground cocoa beans increased significantly (p<0.05) from 0.0233 to 0.0382 W/oCm and 0.0261 to 0.0397 W/oCm respectively as temperature increased from 35 to 55 oC. Effect of moisture, bulk density and temperature on thermal conductivity of sheanut kernel and cocoa bean were found to be significant (p>0.05)