Inside a small transparent square of soft gel, chemistry imitates comfort. Like milk easing the sting of hot peppers, this new artificial tongue mimics that soothing reaction to measure just how fiery a food really is. Created by researchers in China, the flexible sensor binds to the same fiery molecules that trigger pain on the human tongue, then translates them into an electrical signal scientists can read instead of taste.
The team took inspiration from milk’s casein proteins, which latch onto capsaicin, the compound that makes chili peppers burn. They reasoned that if milk can blunt the sensation of heat, it might also serve as a biological key for a sensor that detects it. By combining acrylic acid, choline chloride, and skim milk powder into a gel, then curing it under UV light, they produced a milky, tongue-shaped film that responded to spice within seconds.
Turning Heat Into Data
Capsaicin, piperine from black pepper, and allicin from garlic all create pain-like tingling that is notoriously difficult to quantify. Measuring those sensations usually requires human taste testers or complex lab analyses. But when the artificial tongue was exposed to capsaicin, its electrical current fell measurably within ten seconds. The stronger the spice, the greater the drop. The milk component, acting as both receptor and buffer, allowed the sensor to capture pungency levels ranging from mild to searing.
In tests, the device’s readings aligned closely with human perceptions. Eight pepper types and eight spicy foods, including several hot sauces, were rated both by the gel and a panel of volunteers. The agreement between machine and palate suggested that this milky mimic could eventually save tongues from unnecessary suffering.
“Our flexible artificial tongue holds tremendous potential in spicy sensation estimation for portable taste-monitoring devices, movable humanoid robots, or patients with sensory impairments like ageusia, for example,” said Weijun Deng, the study’s lead author.
Unlike earlier synthetic taste sensors, which could identify sweetness or umami, this design targets pungency itself—the chemical burn often left out of artificial taste studies. The result is a sensor that can distinguish the sting of horseradish from the warmth of ginger and the heat of chili peppers, all using a material that costs little more than a carton of milk and some common lab reagents.
Safer Tasting For Science
To visualize the process, imagine a drop of hot sauce landing on the translucent film. Within moments, the electrical signal dims, like a digital wince. The same compounds that would make a human tester sweat instead trigger a measurable current change in the gel. By capturing that reaction, scientists can quantify flavor intensity without relying on people to suffer through repeated burns.
For now, the artificial tongue remains a proof of concept, but the authors see broad applications. Food manufacturers could standardize spiciness levels without subjective panels. Humanoid robots might one day evaluate flavor profiles with human-like nuance. Even clinical testing for sensory disorders could benefit from a device that speaks the language of taste without needing a functioning tongue.
“The casein-containing artificial tongue could be used to quickly test a food’s spiciness level without putting one’s taste buds at risk,” the researchers concluded in the paper.
In the end, this tiny, milk-infused film translates the heat of chili peppers into numbers, merging human comfort chemistry with technological precision. It is a scientific twist on an age-old truth: sometimes, milk really does make it better.
ACS Sensors: 10.1021/acssensors.5c01329
ScienceBlog.com has no paywalls, no sponsored content, and no agenda beyond getting the science right. Every story here is written to inform, not to impress an advertiser or push a point of view.
Good science journalism takes time — reading the papers, checking the claims, finding researchers who can put findings in context. We do that work because we think it matters.
If you find this site useful, consider supporting it with a donation. Even a few dollars a month helps keep the coverage independent and free for everyone.