Love chocolate? Know why it feels so good

Scientists have described the physical process that occurs in the mouth when a piece of chocolate is ingested, transforming it from a solid to a smooth emulsion that many people find utterly seductive. The multidisciplinary research team at the University of Leeds hopes that by analyzing each stage, they will be able to design a new generation of premium chocolates that have the same feel and taste but are healthier to ingest. The chocolate feeling emerges during the times it is in the mouth due to the way the chocolate is lubricated, either by chemicals in the chocolate itself or by saliva or a mix of the two.

The study, which was published in the scientific journal ACS Applied Materials and Interface, did not look at how chocolate tasted. The inquiry instead concentrated on its feel and texture. The tests were carried out on an artificial 3D tongue-like surface built by the University of Leeds, using a quality brand of dark chocolate. The investigation was carried out using analytical approaches from the engineering discipline of tribology, which included in situ imaging.

Tribology is the study of how surfaces and fluids interact, the degrees of friction between them, and the impact of lubrication: in this example, saliva or chocolate liquids. When we eat chocolate, all of these systems are activated.

When chocolate comes into touch with the tongue, it produces a fatty film that coats the tongue and other surfaces in the mouth. This fatty layer is what makes the chocolate feel smooth in the tongue.

Dr Siavash Soltanahmadi, from the School of Food Science and Nutrition at Leeds and the lead researcher in the study, said: “With the understanding of the physical mechanisms that happen as people eat chocolate, we believe that a next generation of chocolate can be developed that offers the feel and sensation of high-fat chocolate yet is a healthier choice.

“Our research opens the possibility that manufacturers can intelligently design dark chocolate to reduce the overall fat content. “We believe dark chocolate can be produced in a gradient-layered architecture with fat covering the surface of chocolates and particles to offer the sought after self-indulging experience without adding too much fat inside the body of the chocolate.”

According to MINTEL study, revenue from chocolate sales in the UK is expected to rise over the next five years. Sales are predicted to increase 13% between 2022 and 2027, reaching £6.6 billion. The researchers believe the physical approaches employed in the study might be used to the exploration of other foods that undergo a phase shift, in which a material is converted from a solid to a liquid, such as ice cream, margarine, or cheese.

The European Research Council funded this study as part of the European Union’s Horizon 2020 research and innovation initiative