Determination of the tendency of cocoa butter and cocoa mass to crystallize

When manufacturing chocolate products, rapid crystallization allows a high production rate. The crystallization behavior depends on the quality of the raw materials and also the production process, in particular the tempering and cooling. The plant settings must be adapted to the properties of the raw materials. Only by having optimum crystallization can chocolate products be produced that are resistant to bloom formation. Cocoa butter and coca mass crystallize at different rates depending on their origin. Precise evaluation of the quality of the raw materials is hence a prerequisite for manufacturing high quality products.

The crystallization behavior can be determined using a variety of methods and instruments and in practice this leads to differing results. This means the the crystallization properties quoted by suppliers are often very different to measurements made for the purposes of incoming goods inspection.

The objective of this research project is to develop a standardized method for measurement of the crystallization properties. As many companies use not only cocoa butter but also ready-to-use cocoa mass as a raw material, this standardized method must be suitable for both cocoa butter and cocoa mass.

A standard procedure is being drawn up for sample preparation for the respective types of raw material. Different analytical methods (such as differential scanning calorimetry and nuclear magnetic resonance spectroscopy) and different types of instruments are being tested at the Fraunhofer IVV and industrial partners and the results will then be compared. An index will be drawn up for the instruments, allowing categorization of the samples. The small chocolate pilot  plant at the Fraunhofer IVV and the advanced analytical facilities provide an optimum basis for the method evaluation.

Effective evaluation of raw material quality enables optimum adaptation of the production process, and hence improved product quality. Small and medium sized companies (SMEs) that have no R&D department and instrumental facilities will particularly benefit from the project results and will be able to improve their product quality and quality assurance measures.