SchokoSorp

Conching is crucial for the flavor of chocolates and is the most cost-, time- and energy-intensive process during production. A particular challenge is therefore to design this process in a resource-friendly way while maintaining a constant product quality. For the flavor development of chocolates, a redistribution of the cocoa aroma compounds should be achieved in the conche. This requires high mechanical energy input and significantly influences the production costs. Cocoa aroma should be released from the inside of the cocoa particles and be transferred to the sugar surface. As a result, the initially mixed taste of cocoa and sugar turns into the well-known harmonious chocolate flavor. During conching, the little amounts of water contained in the chocolate mass could act as an entrainer for the cocoa aroma. The underlying hypothesis is that the two main components, cocoa and sugar, change their sorption behavior in opposite directions when heated. At the beginning of conching, the little amounts of water contained are exclusively in the cocoa liquor, which is more hygroscopic than sugar and cocoa butter. At higher temperatures, the hygroscopicity of the cocoa liquor decreases and it releases water. Sugar and other sugar substances, on the other hand, show the opposite behavior as they become more hygroscopic when heated and increasingly adsorb water. This can lead to a transfer of water and an associated carry-over of aroma compounds. However, sorption data for different cocoa liquors and sugars at the relevant fineness levels and under conching conditions are lacking in the literature.

In this research project, the focus is therefore on the water vapor sorption behavior of dark chocolate and its raw materials (cocoa liquors, sucrose, emulsifiers), and particularly on its change with increasing conching temperature from 40 to about 80°C. The water vapor sorption behavior the raw materials (cocoa liquors, sucrose, emulsifiers) and of the corresponding chocolates will be analyzed in the temperature range from 20 to 80°C. The temperature-dependent sorption behavior in the conche will be investigated as well. The knowledge gained from these experiments will help to elucidate the mechanisms of aroma diffusion. In case of success, a targeted process optimization can be conducted.