Research takes aim at chocolate challenges in yoghurt

The German chocolate specialist has committed €1.1m to the project, which is being supported with an additional €270,000 from the state of Schleswig-Holstein.

At the end of the two year research project, Herza hopes to have developed a technical process and suitable plant for producing sterile chocolate that can be easily added to yoghurt products.

Chocolate challenges ​

The task of adding chocolate pieces to yoghurt is a tricky one because of the high moisture content of yoghurts and their shelf life demands.

In the moist environment of the yoghurt, the sugar crystals in chocolate can dissolve so that the pieces lose their stability and consistency.

Even more problematic is the bacteria content of the chocolate that finds an ideal breeding ground in the yoghurt causing the finished product to deteriorate quickly.

Faced with these challenges, Torsten Wywiol, managing director of Herza, said: “​Our aim is to develop a technical process and suitable plant for producing sterile chocolate in different shapes and sizes which will help to enhance the sensory quality of the end products.”​

Possible approaches ​

On the shelf life front this means that the sterility of the chocolate has to be guaranteed. Wywiol said this can be harder to achieve than it sounds.

“The constituents of the cocoa are very sensitive. Excessively high temperatures and incorrect cleaning, roasting, grinding or conching impair the quality of the finished chocolate pieces. All that has to be taken into account when you are developing new sterilisation techniques.”​

As for the shape and consistency of the chocolate pieces, Wywiol explained that there are two strategies available.

“One way is to cut down the sugar content of the chocolate so that the individual sugar crystals are covered with a thicker layer of fat as a protection against water. The other possibility is to coat the sugar crystals with emulsifiers or other barrier layers in order to prevent any interaction between sugar and water up to the end of the minimum shelf-life.”​

Herza believes that success with the research project has significant market potential as yoghurt products with chocolate are gaining in popularity. Also, sterile chocolate pieces need no additional processing so dairies can easily add them to their products.