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Gottfried Ziegleder - Articles and news items

UV protection for packaged foods

Issue 4 2007  •  16 November 2007  •  Wolfgang Danzl and Gottfried Ziegleder, Fraunhofer IVV

Transparent plastic packaging is increasingly replacing traditional food packaging made of glass and metal. The advantages of transparent plastic packaging are; its low weight, low cost, design flexibility and the opportunity to present products in an attractive way. However, compared to traditional packaging made of glass, metal, aluminum-laminated films or metallised films, transparent plastic packaging provides less protection against light and also in many cases, a poorer barrier against oxygen.

When are chocolates really finished?

Issue 4 2006, Past issues  •  6 November 2006  •  Julia Strassburg, Nestle Research Center, Vers-chez-les-Blanc, Gottfried Ziegleder, Fraunhofer Institut Verfahrenstechnik und Verpackung and Steve Beckett, Nestle R&D Centre York

Unfinished crystallisation in freshly produced chocolates is one of the major reasons for fat bloom, especially for filled products. Chocolate shells, if insufficiently crystallised, show reduced resistance to oil-migration of fillings. The influence of two production parameters, cooling tunnel time and storage temperature, on the finished state of chocolates is investigated. It is found that the crystallisation in the chocolates is not finished when the products leave the cooling tunnel.

Many confectioners believe the production process of chocolate and confectionery products to be completed once a good temper has been achieved and a product with a shiny gloss and hard finish has been produced. However, this is not the case; many changes continue to occur during the post cooling tunnel time. Seven to twelve minutes in a controlled, low temperature are sufficient to give the majority of the cocoa butter an opportunity to crystallise, but significant liquid fat still remains. A common misconception is that keeping the chocolate at the lowest temperature possible accelerates the crystallisation of the remaining liquid cocoa butter. On the contrary, warmer temperatures in fact support crystallisation – cold temperatures actually decrease diffusion. Diffusion is the basic principle of transport for liquid cocoa butter throughout the already partially solidified chocolate. If diffusion is not possible, the molecules align themselves rather than move. Therefore, just as much attention must be paid to the confectionery after the tunnel as before (Seguine, 1995).

 

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