Effects of convective and microwave roasting on the physicochemical properties of cocoa beans and cocoa butter extracted from this material

The cocoa beans of the Ivory Coast variety were convectively and microwave roasted. The effects of roasting conditions on the principal physicochemical attributes (water and fat contents, total and volatile acidity) of roasted cocoa beans and the properties of fat extracted from this material (acidity, saponification index, iodine index, peroxide value, light refraction coefficient, polar fraction content, and Fatty Acid profile, absorbancy of 1 and 10% solution in hexane) were examined. The characteristics of roasted and raw cocoa beans and their lipid fractions were compared. Results of analyses showed that convective roasting for 35 min at 135 degrees C, air flow rate 1.0mxs(-1) and relative humidity RH of 0.45% caused the least advanced changes in fat quality while microwave roasting promoted oxidation of lipids although the quality of roasted cocoa beans was the best.