Investigation of the Causes of Gloss Inhomogenities on Chocolate Surfaces

Gloss is a main criterion for chocolate quality and hence consumer acceptance. Today, gloss inhomogeneities, i.e. shiny and matt spots on the chocolate surface, remain a problem for manufacturers as these inhomogeneities occur even after apparently optimal pre-crystallization and cooling of the chocolate. An important influence factor is the mould and its material.

It is already known that chocolate gloss after demoulding is highly influenced by the degree of roughness and polarity of the mould material. However, the specific interactions between chocolate and contact material have not yet been fully investigated. 

Current research activities deal with these interactions, focusing dark chocolate in combination with diverse molds/ contact materials (varing in polarity and roughness). It is not yet known in detail how the surface polarity can be influenced by the manufacturing process.

Some selected results will be presented. The surface polarity of contact material as well as chocolate was characterized by contact angle measurement and roughness by atomic force microscopy (AFM). Relevant physicochemical properties of the chocolate were analyzed as well and its gloss measured by gloss meter. It could be proven that the type of mould has a strong influence on the chocolate surfaces and therewith its gloss and formation of gloss inhomogeneities.