Combining Microscopy and Physical Techniques in the Study of Cocoa Butter Polymorphs and Vegetable Fat Blends

Transmission electron microscopy, differential scanning calorimetry and X-ray diffraction have been used to study the cocoa butter polymorphs and blends of cocoa butter with a hydrogenated vegetable fat. The results indicate the presence of six polymorphs and confirm observations made by other workers. Vegetable fat addition affects both the molecular structure and the morphology of the crystals observed. After temperature cycling, a blend containing 50% vegetable fat developed two crystal types and differences in the X-ray pattern were apparent. Correlations could be made between the known molecular structure and the morphology observed in most of the polymorphs. In selected cases, and particularly the blends containing vegetable fat, knowledge of the polymorphic form did not always enable an accurate prediction of morphology