Semi-Solid Processing of Chocolate and Cocoa Butter: The Experimental Correlation of Process Rheology with Microstructure

This paper reports experimental observations on changes in process rheology caused by successive processing of chocolate and cocoa butter in a semi-solid state. Experiments were carried out using a multi-pass rheometer where successive extrusion passes were used with different time delays between each pass. The results show that both chocolate and cocoa butter are sensitive to process history. Additional microstructural data was obtained by using an in situ X-ray facility coupled to the multi-pass rheometer and results obtained using this technique indicate that the process rheology changes are coupled with matching changes in the amount of crystal phase present.