Unwelcome Fat Blooms On Chocolate

Chocolate lovers worldwide are all too familiar with the profound misery experienced when they unwrap a piece of their favorite treat and see it covered in a white haze. These so-called chocolate fat blooms—when fats migrate to the surface of chocolate and recrystallize there—are also a bane of the chocolate industry, which would like to increase the shelf life of its products. A research team led by Svenja K. Reinke of the Technical University of Hamburg, in Germany, has used small-angle X-ray scattering to track the structural changes in chocolate when this blooming occurs (ACS Appl. Mater. Interfaces 2015, DOI: 10.1021/acsami.5b02092). The team showed that when fats begin to migrate to the surface through pores in the chocolate, they dissolve cocoa butter (a mixture of triglycerides). This dissolution destroys the crystalline structure of cocoa butter, which is responsible for the delightful texture of chocolate. Thus, the tasty treat turns into a stale disappointment. The new study may help thwart this travesty by revealing how chocolatiers can better control porosity and migration pathways in chocolate.