Chocolate is made of cocoa butter, cocoa solids and sugar. It is often found in other products such as biscuits, sweets and confectionary. As the popularity of chocolate has steadily risen since 1914, more emphasis and effort has been put into formulating the perfect blend of chocolate.
Cocoa butter is the main component that determines the characteristic of the chocolate. Cocoa butter is able to exist in six different polymorphic forms, each with a different crystal structure and melting point. Identifying the different polymorphic forms of chocolate can done by using X-ray Diffraction (XRD). XRD provides unique signature peaks for each individual polymorphic form.
Using XRD for the characterisation of chocolate is hindered by the presence of sugar crystals. The highly crystalline nature of sugar produces a diffraction pattern with extremely high intensity, which renders the identification of chocolate peaks to be almost impossible. Thus, the removal of sugar is a priority in XRD testing of chocolate. Cebula and Ziegleder (1993) have proposed a water dissolution removal method. However the feasibility of the method has come into question, due to the apparent difficulty in dissolving fine sugar out of a matrix of cocoa butter fats. In this report, the objectives are to verify the dissolution method and if feasible to determine the minimum time required for the sugar removal process.
The results show that the method proposed by Cebula and Ziegleder is highly effective for a wide range of commercial chocolates. The actual time taken for sugar removal is significantly less than the recommended time. Also, after the sugar removal process, all the chocolate specimens still display apparent Form V diffraction peaks. This is evidence that the dissolution process does not change the cocoa butter structure and thus is an essential and effective procedure in the XRD testing of chocolates.