Why is chocolate so good? Answer may lie in lubrication

Scientists have decoded the physical process that takes place in the mouth when eating a piece of chocolate . The candy transforms from a solid into a smooth emulsion that many people find downright overwhelming.

The interdisciplinary research team from the University of Leeds, in the United Kingdom, analyzed each of the stages of the consumption process. The findings could lead to the development of a new generation of luxury chocolates that will have the same feel and texture, but will be healthier.

The researchers point out that the sensation caused by chocolate arises by the form how is it lubricated either by the ingredients, the saliva or a combination of the two.

Fat plays a key role almost immediately when a piece of chocolate is in contact with the tongue. After that, the solid cocoa particles are released and become important in terms of tactile sensation, so the fat deeper inside the chocolate plays a very limited role and can be reduced without affecting the sensation of the chocolate.

“The science of lubrication provides mechanistic insights into how food actually presents itself in the mouth. You can use this knowledge to design foods with better taste, texture or health benefits,” explains Anwesha Sarkar, Professor of Colloids and Surfaces at Leeds School of Food Science and Nutrition, in a statement.

The expert says that if a chocolate has 5% fat or 50% fat, it will still form droplets in the mouth that cause the delicious sensation. However, it is the location of the fat in the chocolate composition that matters at each stage of lubrication.

“We’re showing that the fat band needs to be on the outer layer of the chocolate, that’s most important, followed by an effective coating of the cocoa particles by the fat, which helps make chocolate so good,” he adds.

feel and texture

The study, published in the scientific journal ACS Applied Materials and Interface, did not investigate the question of the taste of chocolate. Instead, researchers focused on its feel and texture.

The tests were conducted using a luxurious brand of dark chocolate on a 3D surface similar to an artificial tongue designed at the University of Leeds. Experts used analytical techniques from a field of engineering called tribology to conduct the study, which included imaging.

Tribology deals with how surfaces and fluids interact, the levels of friction between them, and the role of lubrication: in this case, saliva or chocolate liquids. These mechanisms all happen in the mouth when chocolate is eaten.

When chocolate is in contact with the tongue, it releases a greasy film that coats the tongue and other surfaces in the mouth. It is this greasy film that makes the chocolate soft the whole time it is in the mouth.

“By understanding the physical mechanisms that happen when people eat chocolate, we believe that a next generation of chocolate can be developed that can offer the sensation of high-fat chocolate while being a healthier choice,” said Siavash Soltanahmadi. , from Leeds School of Food Science and Nutrition and principal investigator of the study.

For the expert, the research opens up the possibility that manufacturers can intelligently design dark chocolate to reduce the overall fat content.

“We believe that dark chocolate can be produced in an architecture of gradient layers with fat covering the surface of chocolates and particles to deliver the sought-after self-indulgence experience without adding too much fat within the body of the chocolate.”

The researchers suggest that the physical techniques used in the study can be applied in the investigation of other foods that undergo a phase change, where a substance changes from a solid to a liquid state, such as ice cream, margarine or cheese.