"A major challenge for the chocolate industry is the fact that cocoa butter has to be crystallised in stable form," he told FoodProductionDaily.com. "Because if the crystals within the chocolate have different melting points, then some parts of the chocolate will melt before other parts. It will become sticky, and this is the challenge from the technology point of view."
As a result, new processes are constantly being developed to improve the texture of certain foods, and tailored microstructure has become a central discipline in this endeavour. Indeed, tailored microstructure in food applications was a major topic at the recent International Congress on Engineering and Food (ICEF) in Montpellier, France.
The conference outlined recent achievements in the field crystallising cocoa butter. One product mentioned in a seminar conducted by Dr Erich J Windlab of the Swiss Federal institute of Technology in Zurich was Buhler's SeedMaster. This is designed to replace conventional processes of precrystallising the chocolate mass to produce chocolate with denser texture and higher strength.
"The SeedMaster is a means of precrystallising cocoa butter and so-called CBEs (cocoa butter equivalents)," said Bobzin. "These are polyforms - in other words the different forms of fats crystallise in a complex way. Conventional processing tends to create what are known as beta-5 crystals. But with SeedMaster, we are able to make even smaller more compact crystals called beta-6."
This is significant for a number of reasons. For a start, it can enhance the lifetime of a product. "In chocolate, the fat tends to go out to the surface overtime, and this makes the product go rancid," said Bobzin. "But if the crystals are more compact, this acts as a filter. In addition, the chocolate tastes smoother."
It would appear however that research into chocolate production is a never-ending task. Manufacturers are constantly looking at new ways of improving their product, and the next topic of research for Bobzin is the debacterisation of cocoa.
The problem with cocoa, he says, is that it does not develop its full flavor before it has undergone a long series of processing operations. The first step,fermentation, takes place on the cocoa plantations, but this is often carried out without any special hygienic precautions.
As a result, the cocoa beans supplied to chocolate factories may be heavily contaminated by microbes. Buhler is now working on ways of destroying these microorganisms without affecting the sensory properties of the product.
Microbial contamination is concentrated on the surface of the beans. As a logical consequence, the Buhler debacterisation process focuses on treating the whole beans, exposing them briefly to very high temperatures and the action of steam. Heat and humidity destroy both bacteria and spores. The inside of the beans is not affected, which is advantageous for the success of the subsequent roasting process.