Fat Bloom management is the key to healthier and tastier chocolates

Have you noticed the changes occurred in chocolate after being left in a room at a high temperature? This is an occurrence called fat bloom, which the crystal structure of cocoa butter takes place.

Fat bloom is harmless; however, according to Svenja Reinke the lead author of Hamburg University of Technology (TUHH), it’s still “causes millions in damage to the food industry” due to customer complaints and quality-related rejections.  Hence, Nestlé and the Hamburg University of Technology got the DESY synchrotron’s high brilliance X-ray source PETRA III on the case.

A study conducted at Germany’s Deutsches Elektronen-Synchotron (DESY) could make one of the worlds most beloved foods look even better, if not exactly taste better, by removing fat bloom on the chocolate.

Cocoa butter is natural fat extracted from cocoa beans and is an ingredient of chocolate. When cocoa butter and other liquid fats seep through the surface of the chocolate and eventually crystallize, fat bloom can arise.  In addition, liquid filling and nougat can expedite the formation of fat bloom.  “This can happen when liquid chocolate cools down in an uncontrolled manner and unstable crystals form, for example,” Reinke added. “But even at room temperature, a quarter of the lipids contained in chocolate are already in a liquid state.”  And the longer chocolate is stored and the higher the temperature, the more likely fat blooming is observed.

However, according to Stefan Palzer of Nestle, despite the fact fat bloom does not actually constitute deterioration in the quality of the product; the visual change associated with it can lead to a large number of consumer complaints. “This is why fat bloom continues to be one of the most important quality defects in the confectionery industry.”

By means of DESY’s PETRA III x-ray tool, additional knowledge of the how and why of fat bloom in chocolate were gained.  The study analyzed some samples of chocolate based on cocoa, sugar, cocoa butter, and milk powder, its main ingredients.

In order to investigate how fats transfer, the samples were treated with a few drops of sunflower oil and documented their observations.  Once the liquid fat changes chocolate’s internal structure, this makes the chocolate softer, therefore facilitating lipid migration.

The observations allow the food industry to develop concrete approaches for eliminating or reducing fat bloom, hence ease the quantity of customer complaints and quality rejections.


The study was published in the journal Applied Materials and Interfaces.




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