What makes chocolate so irresistible?

Studying edible phase change materials such as chocolate can be extremely beneficial as it can help design healthier food.

The sweet and rich taste of chocolate is a sensorial treat that many enjoy, but is that all that makes the sweet irresistible?

Scientists from the University of Leeds have now unravelled the mystery behind what happens when the chocolate melts in your mouth.

While studying the gradual dissolvement of chocolate chunks, scientists found that the sensation of chocolate melting on your tongue comes from the lubrication provided by saliva when it dissolves the sugar particles, or from ingredients used to make the chocolate.

Published in ACS Applied Materials and Interfaces, the study saw researchers focusing on the texture and feel of chocolate rather than its taste. They used techniques employed in tribology— the study of friction, lubrication and interaction between surfaces— to test a luxury brand chocolate on an artificial tongue-like structure. Four different samples of dark chocolate were used.

Analysing the different stages of chocolate sensation, from first contact with tongue to mixing with saliva, scientists found that a fatty layer of film covers the tongue and the mouth. The smoothness provided by the film between the surface of the mouth and chocolate is what gives the rich, melt-in-your-mouth sensation.

“We are showing that the fat layer needs to be on the outer layer of the chocolate, this matters the most, followed by effective coating of the cocoa particles by fat, these help to make chocolate feel so good,” Anwesha Sarkar, study co-author and a professor at the University of Leeds, said in a press release.