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Cracking and Effect of Microstructure and Compactness on Fat
Migration in Chocolate Pralines
N. Loréna, L. Svanberga,b, E. Windhabb, L. Ahrnéa
a
SIK – Swedish Institute for Food and Biotechnology, Box 5401, SE-402 29
Gothenburg, Sweden
b
Swiss Federal Institute of Technology, Zurich, Institut für Lebensmittelwissenschaften,
LFO E 12.1,ETH Zentrum, CH-8092 Zürich, Switzerland
Chocolate pralines are luxury products that are associated with good taste and well-being. The
demands from consumer perspective regarding the quality of pralines are therefore often high.
Cracking and fat bloom are two phenomena that can make the pralines unattractive for the
consumers and therefore a lot of pralines are wasted.
Chocolate pralines are complex food consisting of solid particles of cocoa powder, sugar and
possibly milk powder surrounded by a continuous fat phase which is divided into a liquid and
crystal fraction. In pralines with fat-based fillings, liquid oil can migrate through the chocolate
shell and induce fat bloom on the praline surface. The structure of the crystal fraction of the
cocoa butter is therefore crucial to be able to retard the fat migration. Formation of the fat crystal
structures in model chocolate have been determined by confocal laser scanning microscopy,
image analysis and DSC1. In addition, fluorescent fatty acid analog migration has been
measured by fluorescence recovery after photobleaching in model chocolate2. In this
presentation, effects of tempering and addition of solid particles on the fat crystal structure and
fluorescent fatty acid analog migration in model chocolate will be demonstrated.
In addition to pralines with fat based fillings, confections with a fruit based filling is an increasing
product category motivated by a cumulative consumer demand for healthier snacks with
reduced calorie content. The fillings in these products often have a high water activity that also
entails quality defects. However these have not at all been investigated and characterized to the
same extent as those associated by fat migration and fat bloom. Here, work that aims to
elucidate the cracking phenomena in chocolate pralines by investigating the effect of product
geometry, shell thickness and water activity in filling will be presented.
1
Svanberg, L.; Ahrné, L.; Lorén, N.; Windhab, E. (2011) Effect of sugar, cocoa particles and lecithin on
cocoa butter crystallisation in seeded and non-seeded chocolate model systems. J. Food Engineering.
104, 70-80.
2
Svanberg, L.; Ahrné, L.; Lorén, N.; Windhab, E. (2011) Effect of pre-crystallization process and solid
particle addition on microstructure in chocolate model systems. Food Research International (in press).