In English

Crack formation in chocolate pralines

Katarina Slettengren
Göteborg : Chalmers tekniska högskola, 2010. 67 s.
[Examensarbete på avancerad nivå]

Chocolate pralines are complex food products that contain a soft filling surrounded by a chocolate shell. One problem with pralines is that the filling often starts to migrate through the shell which causes major structural changes that, for water or liquor based fillings, could result in cracking of the shell. Cracking is one of the major issues that lead to reduced shelf life in chocolate pralines. The main suggestions for crack formation are that cracks form due to moisture or ethanol migration through the chocolate shell, or due to an unbalanced distribution of moisture in the filling that causes some parts to shrink and other to expand. In this work, two praline geometries and four different model fillings (with water activities (aw) between 0.67 and 0.99) were analysed with respect to chocolate shell cracking during storage. The pralines were stored for 28 days, during which high resolution images of the pralines were collected and analysed by a digital colour imaging system. Furthermore, water activity measurements in the shell, combined with weight changes in the pralines gave information on migration properties during storage. The results showed that pralines with aw 0.99 in the model filling cracked first and to the highest percentage for both geometries. Pralines with model filling aw 0.86 and aw 0.78 had quite similar results to each other, and cracked to a considerably lower percentage than pralines with model filling aw 0.99. For model filling aw 0.67, square pralines did not crack at all while round pralines cracked at a low percentage. Round pralines started to crack first for all model fillings during the storage period. The major conclusions that can be drawn from this work are that both water activity (aw) in the model filling and praline geometry have an impact on crack formation in chocolate pralines.



Publikationen registrerades 2010-12-16. Den ändrades senast 2013-04-04

CPL ID: 131122

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