For many it’s simply irresistible and their favorite candy: chocolate. Its success is presumably due not only to its taste but also to its smooth texture, which is achieved by a process known as conching and the addition of lecithin. Scientists at the Technical University of Munich (TUM) have now explained how all the ingredients interact at the molecular level and what gives chocolate its characteristic texture.
“There are many theories about the role of lecithin in the production of chocolate,” says Professor Heiko Briesen, TUM Chair of Process Systems Engineering, with reference to the study. But exactly what happens at the molecular level was still a mystery. It was also unknown what kind of lecithin best enhances the flow characteristics of the chocolate mass. To clarify this, TUM scientists set up what is known as a molecular dynamic simulation. These dynamic simulations are used to model the interactions of atoms and molecules.
The binding of lecithin to sugar is key
Their investigations sought to answer some key questions. “Our study,” says Professor Briesen, “centered on the question of how strongly different lecithins bind to sugar particles in chocolate.” The scientists found that various lecithins – they investigated six types – differ in their ability to “associate with” sugar.
The findings of the TUM scientists have provided chocolate manufacturers with valuable pointers, especially in view of the fact that chocolate production chiefly uses lecithin derived from soybeans. However, because the supply of genetically unmodified soybeans is shrinking, molecular simulations can spare food chemists the need to run tedious, time-consuming trial-and-error tests to determine which lecithin they should use in their chocolate formulations. “I’m convinced that molecular dynamics will be a keystone of food research in the future,” says Briesen.
The study on the web: link.
Publication: M. Kindlein, M. Greiner, E. Elts und H. Briesen: Interactions between phospholipid head groups and a sucrose crystal surface at the cocoa butter interface, Journal of Physics 2015.