Do you like chocolate? Silly question, right, so how about: Why do you like chocolate? Is it the sweet taste? The burst of joy you get from the first bite alone? Or is it perhaps the way it slowly melts on your tongue, how it dissolves and deliciously coats the inside of your mouth before you swallow it all down and reach for the next piece?
As you might be able to tell, I identify as a chocoholic. For me, chocolate is one of humanity’s best inventions for all three of the above reasons. But scientists from the University of Leeds, UK, have focussed on the latter for a study published this month in the journal ACS Applied Materials and Interfaces.
Lead researcher Siavash Soltanahmadi from the university’s School of Food Science and Nutrition and his team determined that it is the mouth-feel of chocolate that triggers our delight. Their research results say: It’s all about lubrication.
That melty, chocolatey deliciousness that fills your entire mouth when you’re enjoying a treat arises from the way the chocolate is lubricated―from the way certain ingredients mix with our saliva.
And the most relevant ingredient for that is fat.
Not exactly surprising, but still a little disheartening for the health-conscious among us. There is good news though: Soltanahmadi and his fellow researchers claim they have found a way to make chocolate healthier without changing its characteristic gooey goodness. Spoiler alert: It’s all about the location of the fat inside the chocolate.
Fatty cocoa butter makes for good mouth feel
But first, let us take a step back. Chocolate is made up of several components. There are the solid solids, if you will (sugar and cocoa particles), and a solid that turns liquid: Cocoa butter, the aforementioned fat. Cocoa butter is solid at low temperatures, but once it enters our mouth and hits our tongue, it turns into an oily liquid.
“That’s what gives you the smooth feeling on your tongue that we all like,” Soltanahmadi told DW.
To figure out how exactly that appealing feeling in our mouth comes to be, the researchers divided the eating process into three stages: First, you lick the chocolate while you take a bite of it. Then the top layer of the chocolate melts in the mouth, bringing out the liquified cocoa butter. And finally, the chocolate components mix with our saliva, turning into an emulsion that we eventually swallow. Happily.
Excuse me while I test this theory.
Chocolate and the artificial tongue
Mmmh. Can confirm. Back to the science: To analyse chocolate’s mouth feel over these three stages, Soltanahmadi and his research team employed an apparatus best described as an artificial tongue.
“It’s a machine that holds a tongue-like surface,” Soltanahmadi said. “We collected data from real human tongues and analyzed them to have an idea of the texture of our tongue. Then we came up with an average, put that into a model and 3D-printed some molds.”
That’s how the researchers ended up with models that look and act “like [a] tongue,” Soltanahmadi said.
The scientists rubbed dark chocolate on the artificial tongue, then rubbed the tongue against another surface doubling as a palate to analyze what would happen with the chocolate and how the components would dissolve.
Human nature too fickle for chocolate testing
But why not simply use human testers? I would have happily flown to the UK to volunteer as a chocolate taster for this experiment, and I imagine it wouldn’t have been too difficult to find a few others willing to eat chocolate in the name of science.
“One of our aims with this was actually to reduce the number of human panelists [or testers] needed, and the reason for that lies in the nature of humans,” Soltanahmadi explained. “Me and you, we can try the same chocolate and we’d describe it in different ways. We’re trying to reduce that and create more lab-based measurements.”
In short, humans aren’t suitable to produce reliable, comparable data when it comes to testing the mouth feel of chocolate. There goes my dream job.
Less fat, same melty mouth feel…
All disappointment aside, test runs with the artificial tongue showed that the level of lubrication that makes for chocolate’s pleasant mouth feel can be achieved with a fat content lower than that of most current chocolates.
“We’re not aiming for zero-calorie chocolate,” Soltanahmadi said. “I’m not sure that’s achievable. But we aimed to reduce the cocoa butter, the fatty part. Because in our observation we saw that rather than the amount of the fat, the location of the cocoa butter is more important.”
The fat should go mostly on the surface of the chocolate and around the solid cocoa particles. The body of the chocolate, the researchers have found, can have less fat than it currently has and more cocoa particles.
“This would be healthier and the chocolate would have fewer calories as well,” Soltanahmadi said.
… but not quite as sweet
Lower-calorie chocolate! That’s great news! One little downer for milk chocolate lovers like me: The resulting treat won’t be quite as sweet. The amount of cocoa particles is what translates to the percentage that you see printed on chocolate packaging (i.e. 70 per cent or 85 per cent), and as we know, the higher the percentage, the darker and the more bitter the chocolate.
If you are a dark chocolate lover, good for you. The rest of us will have to remember the age-old saying: You can’t have it all.