Effect of Superheated Steam and Convection Roasting on Changes in Physical Properties of Cocoa Bean (Theobroma cacao)

Abstract

Roasting is one of the important unit operation steps in cocoa base food industries. Cocoa beans (Theobroma cacao) were roasted using superheated steam oven (Healsio, AV-1500V, SHARP) in superheated steam mode and convection mode operated at three set of temperatures (150°C, 200°C and 250°C) for 5 to 35 min. The changes occurred in the physical properties; colors, texture (hardness and fracturability), moisture content and heat inside the beans were examined at the same temperature and time. During superheated steam roasting the color values were more affected than convection roasting. Hardness of the cocoa beans were more affected by the convection roasting mode as compared to superheated steam while fracturability values were more affected in superheated steam mode as compared to convection roasting. The moisture losses of the cocoa beans were lower at each temperature in superheated steam roasting as compared to convection roasting whereas the heating rate inside cocoa beans was higher in superheated steam.