Few people can say no to this food, and if not, just tell the Mayans, who 2,000 years ago were already drinking a beverage made with water and cocoa beans.
Nothing like a little piece of chocolate to save the day. Who wouldn't like the sensation that this food generates throughout the body when it reaches the mouth? Few can say no to it, even less knowing that it is beneficial both for our emotional state (numerous studies have shown that this little piece improves our mood, our creativity and even has aphrodisiac properties, you know) and for our health (it helps control cholesterol and even regenerates our memory). Well, who wouldn't like it?
Just tell it to the Mayans, who 2,000 years ago were already drinking a beverage prepared with water and cocoa beans, the basic ingredients of chocolate, which they roasted and ground. Since then, at least, the pleasure of tasting this delicacy has only grown and grown. The Aztecs later learned about chocolate drinks from their ancestors, who began to work with different flavors. In addition, this civilization already found in cocoa beans great remedies for many of the most common ailments.
Tasting it has never left anyone indifferent, of course, and that feast of sensations that chocolate generates has more background than you think. It has to do with a series of chemical processes that are set in motion when our saliva and the ingredients of the chocolate itself come into contact. When that happens, there's no turning back: you'll want more and more and more. But how is it possible that we like it so much?
The mystery is in the fat
Anwesha Sarkar, professor of colloids and surfaces at the Leeds School of Food and Nutritional Sciences, answers the big question, “The science of lubrication gives us the mechanistic information we need to understand how food really feels in the mouth.” With this in mind, Sarkar has led a team to thoroughly investigate the intricacies of chocolate melting on our tongues. “Using the knowledge this can offer us would help us design foods with better taste, texture or health benefits,” he explains.
Fat is the key to this whole mystery. It's the fat that plays a role almost immediately when a piece of chocolate passes through someone's lips. Once that happens, the solid cocoa particles that make it up are released and become central to the tactile sensation of taste at that moment. In other words, the deeper fat inside the chocolate plays a fairly limited role and could be reduced without having an impact on the sensation of this food.
“Whether you have 5 % or 50 % fat, chocolate will still form droplets in the mouth, i.e. generate that characteristic sensation. What matters at each stage of tasting is the location of the fat within the composition of the chocolate itself, something that has rarely been investigated,” says Sarkar. “We are showing that the fat layer should be on the outer layer of the chocolate, this is the most important thing, followed by an effective coating of the cocoa particles with fat, which help the chocolate taste so good.” The study he led, published in the scientific journal ACS Applied Materials and Interface, focused precisely on touch and texture.
Exploring the mechanisms of chocolate
Using a luxury brand of dark chocolate on a surface similar to an artificial 3D tongue designed by members of the University of Leeds itself, the researchers used analytical techniques from a field of engineering called tribology to conduct the research.
The basis of the work stems from research into how surfaces and fluids interact, the levels of friction between them, and the role that lubrication – in this case, saliva or product fluids – plays. All these mechanisms are happening in the mouth when chocolate is eaten: when it is in contact with the tongue, it releases a greasy film that coats it, as well as other surfaces. It is this greasy film that makes the chocolate feel smooth throughout the time it is in the mouth.
“Our research opens up the possibility that manufacturers can intelligently design dark chocolate to reduce total fat content. We believe that dark chocolate can be produced in a fat-degraded layered architecture with fat coating the surface of the chocolates and particles to deliver the sought-after experience of self-indulgence without adding too much fat within the chocolate body.”
Chocolate sales revenues are forecast to grow over the next five years, according to research from business intelligence agency MINTEL. Specifically, in the UK, for which the research was conducted, sales are expected to grow by 13% between 2022 and 2027 to £6.6 billion. The researchers believe that the physical techniques used in the study could be applied to the investigation of other foods that undergo a phase change, where a substance transforms from solid to liquid, such as ice cream, margarine or cheese.