Influence of mold materials on the gloss of chocolate bars

verfasst von
Dana Middendorf, Ute Bindrich, Knut Franke

The gloss of a chocolate bar surface is one of the main quality parameters appreciated by the consumers, despite texture and taste. The chocolate should exhibit a high and uniform gloss. It can be expected that the chocolate gloss is influenced both by the processing, especially appropriate pre-crystallization, and by the characteristics of the mold material surface which is in direct contact with the chocolate during solidification. So far, the correlation between surface properties of the mold material in microscopic scale and the resulting chocolate gloss is not really understood and deviations in gloss, like local matte areas, are still found on chocolate bars after de-molding. Therefore, different materials were investigated with respect to the gloss of the chocolate molded at these surfaces. Materials and chocolate were characterized with respect to their microstructure by atomic force microscopy (AFM) and their surface energies. AFM analyses covered topography, including roughness, and adhesion forces. With respect to chocolate gloss, a distinct influence of the surface roughness could be detected. Only very flat surfaces with a low roughness of less than few micrometers can produce high gloss chocolates. Additionally, the surface energy also affects the gloss indicating that the interactions of the liquid chocolate during molding and the mold material surface are relevant. These correlations were implemented in a model enabling the prediction of chocolate gloss from mold material properties.

Institut für Lebensmittelwissenschaft und Humanernährung
Arbeitsbereich Lebensmitteltechnologie