Chinese Researchers' Artificial Tongue Uses Milk Science to Precisely Measure Food Spiciness
- MM24 News Desk
- Nov 1
- 3 min read
Xinjiang University's milk-based artificial tongue detects capsaicin in seconds, matching human taste perception for accurate spiciness measurement in foods. Credit: Weijun Deng
Researchers from China's Xinjiang University have developed a flexible, gel-based artificial tongue that can accurately measure the spiciness of foods by leveraging the same science that makes milk an effective remedy for spicy food burn. The prototype sensor, detailed in ACS Sensors, uses skim milk powder to detect capsaicin—the compound behind chili pepper heat—and could revolutionize food quality control and dietary management.
“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,” says Weijun Deng, the study’s lead author at Xinjiang University.
Currently, measuring flavor compounds in foods requires human taste testers and complex laboratory methods, according to the research team's publication. As an alternative, scientists worldwide are developing artificial tongues capable of measuring tastes like sweet and umami. However, replicating the stinging, tingling, or burning sensations produced by compounds like capsaicin in chili peppers has proven particularly challenging for synthetic materials.
The breakthrough came when Professor Jing Hu and colleagues realized they could borrow from nature's own solution. They noted that milk's casein proteins effectively neutralize pepper heat by binding to capsaicin molecules. The team wondered if they could incorporate this biological mechanism into an electrochemical sensor, creating what they call a "biomimetic" artificial tongue.
To build their spice-detecting device, the researchers created a tongue-shaped film by combining acrylic acid, choline chloride and skim milk powder, then exposed the solution to UV light. The resulting flexible and opaque gel conducted an electrical current. The real magic happened when they added capsaicin: within just ten seconds, the electrical current decreased significantly as the casein proteins bound to the spicy compound.
This electrical change provided a measurable signal that directly correlated with spiciness levels. Initial testing revealed the milk-containing material could detect capsaicin concentrations ranging from below human detection thresholds all the way up to levels perceived as painfully spicy. The sensor wasn't limited to just capsaicin either—it successfully detected other pungent compounds found in common spicy ingredients including ginger, black pepper, horseradish, garlic and onion.
In practical tests, the research team put their invention through its paces with eight different pepper types and eight commercially available spicy foods, including several popular hot sauces. They compared the artificial tongue's readings against ratings from a human taste-testing panel, and the results showed remarkable alignment between the electronic sensor and human perception.
The implications extend far beyond simply avoiding overly spicy food. For food manufacturers, this technology could provide consistent, objective quality control for spice levels in products. For healthcare, it could help create customized diets for patients with sensory impairments who cannot accurately perceive spiciness themselves. The researchers even envision this technology being incorporated into humanoid robots that could taste-test foods on behalf of humans.
What makes this approach particularly clever is how it mimics biological processes rather than fighting them. While other artificial tongues struggle to replicate the complex sensation of spiciness, this milk-inspired sensor works with the same biochemical principles that our own bodies respond to. It's not just measuring electrical properties—it's literally detecting when casein proteins bind to spicy compounds, much like what happens in our mouths when we drink milk to cool the burn.
The research demonstrates that sometimes the most sophisticated technological solutions can be found by looking at how nature already solves the problem. As artificial intelligence and robotics continue to advance, having sensors that can accurately perceive the world as humans do becomes increasingly valuable. This milk-powered artificial tongue represents a significant step toward bridging that gap between human sensation and electronic measurement.
Comments