Scientists took X-rays of chocolate in an indulgent study, and the findings could lead to better quality treats.
A team of researchers used X-rays to look at ways to improve the quality of chocolate, and gained insight into what causes unpleasant white "fat blooms" that sometimes form on the sweet, DESY reported.
"Although fat blooming is perfectly harmless, it causes millions in damage to the food industry as a result of rejects and customer complaints," said the main author of the study, Svenja Reinke, from the Hamburg University of Technology (TUHH). "Despite this well-known quality issue, comparatively little has been known until now about its root causes."
Fat blooms form when liquid fats, such as cocoa butter, move through the chocolate to the surface and crystallizes.
"This can happen when liquid chocolate cools down in an uncontrolled manner and unstable crystals form, for example. But even at room temperature, a quarter of the lipids contained in chocolate are already in a liquid state," Reinke said.
The researchers used DESY's x-ray source PETRA III to observe how the fat blooming process works. They looked at the behavior of different mixes of ingredients commonly seen in chocolate, such as "cocoa, sugar, milk powder and cocoa butter." The samples were ground into a fine powder and were scanned with the revealing X-rays. A few drops of sunflower oil were place on each sample to show how the fat would move in the chocolate.
"First of all, wetting takes place within seconds. The oil penetrates very quickly into even the smallest pores, probably through capillary action," Reinke said. "Over a period of hours, the liquid fat dissolves additional crystalline lipid structures, which makes the entire structure of the chocolate softer. This in turn increases the migration of lipids."
The findings could allow the food industry to develop new ways to reduce these bothersome fat blooms.
"One consequence might, for example, be to reduce the porosity of the chocolate during manufacture, so that the fat migrates more slowly," Reinke said. "Another approach is to limit the amount of fat that is present in a liquid form by storing the product in cool, but not too cold, conditions. 18 degrees Celsius is ideal."
The findings were published in a recent edition of the journal Applied Materials and Interfaces.
