A team of researchers led by the University of Leeds has recently decoded the physical process which takes place in the mouth when chocolate is eaten, as it changes from a solid into a smooth emulsion that tastes so good to most people. These findings may help develop a new generation of luxury chocolates that will still have the same feel but be healthier.
In the moments after the chocolate enters the mouth, the unique, tasty sensation arises from the way the chocolate is lubricated, either from the ingredients in the chocolate itself, or from saliva, or a combination of the two. Fat plays a key role in the first part of this process, after which cocoa particles are released and become more important in terms of tactile sensation. Thus, fat inside the chocolate in fact plays a rather limited role, so it could be reduced without losing the irresistible feel or sensation of chocolate.
“Lubrication science gives mechanistic insights into how food actually feels in the mouth. You can use that knowledge to design food with better taste, texture, or health benefits,” said study senior author Anwesha Sarkar, a professor of Colloids and Surfaces at Leeds.
“If a chocolate has five percent fat or 50 percent fat it will still form droplets in the mouth and that gives you the chocolate sensation. However, it is the location of the fat in the make-up of the chocolate which matters in each stage of lubrication, and that has been rarely researched. 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, which help to make chocolate feel so good.”
The scientists conducted tests using a luxury brand of dark chocolate on an artificial 3D tongue-like surface. Then, through analytical techniques from a field of engineering called tribology – which investigates how surfaces and fluids interact – they discovered that, when chocolate gets into contact with the tongue, it releases a fatty film which makes it feel smooth throughout the entire time it is in the mouth.
“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,” said study lead author Siavash Soltanahmadi, an expert in Food Science and Nutrition at Leeds.
“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,” he concluded.
The study is published in the journal ACS Applied Materials & Interfaces.
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