They discover why chocolate seems irresistible to us

Chocolate seems irresistible to us, not only because of the exquisite taste of cocoa. Researchers from the University of Leeds (UK) have verified that the ingredients of chocolate itself interact with saliva, generating a soft fatty film that coats the tongue and makes this product creamy throughout its stay in the mouth. .

Scientists from the School of Food Sciences and Nutrition at the University of Leeds, UK, have discovered why chocolate is so irresistible, and that it’s not just down to taste, but also to the process in which it’s made. is which changes in the mouth from a solid emulsion to a smooth emulsion due to its own ingredients and the combination with saliva.

The study, whose findings were published in the journal Applied materials and ACS interface, analyzes in depth the physical process that takes place in the mouth when consuming a piece of chocolate and the pleasure derived from its touch and texture. Specifically, the lubricating behavior of this phase change material (PCM).

Fat plays a key role the moment a piece of chocolate comes into contact with the tongue, after which the solid cocoa particles are released and become important in terms of tactile sensation.


Chocolate research in an artificial language

chocolate, cocoa, fat, tongue, pleasureSearch tables. / Siavash Soltanahmadi et al./ACS Applied materials and interface

The tests were carried out with four commercial samples of chocolate (Lindt Excellence, Lindt & Sprüngli, UK) with a cocoa content of 70-99% by weight, on a surface similar to an artificial tongue. The researchers used analytical techniques from a field of engineering called “tribology”, which studies the friction, wear and lubrication that occur during contact between moving solid surfaces.

In this case, they checked this interaction between the ingredients of the chocolate itself and saliva. On the taste buds side,the determining mechanisms were the formation of cocoa butter bridges between the particles of this substance and the fat of the emulsion droplets“, according to the study.

The authors also verified that the product, when it comes into contact with the tongue, releases a film of fat that covers this organ and other surfaces of the mouth. This film is what makes this product smooth the whole time it’s in your mouth.

The unprecedented results of this study, supported by far-reaching lubrication theories, reveal how the tribological mechanism of licking shifted from fat-dominated solid lubrication (saliva-poor diet) to watery lubrication (saliva-dominated diet). saliva), which resulted in an increase in the coefficient of friction“, point out the authors in their study, where they also point out”the formation of the distinctive hydrodynamic viscous film” in the language.

Remove the fat but not the taste

The researchers also note that the deeper fat in chocolate plays a rather limited role, so it could be reduced without impacting the feeling of drinking pleasure.

The team believes this work can help develop a new generation of chocolates that have the same feel and texture, but are healthier to eat.

Additionally, the physical techniques used could be applied to study other foods that undergo a phase change, where a substance changes from a solid to a liquid, such as ice cream, margarine or cheese.

The project in which this work was framed received funding from the European Research Council under the European Union’s Horizon 2020 research and innovation programme.

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