It's a well-known fact that if you're trying to cool your mouth after eating spicy food, you should drink milk, not water. Bearing that fact in mind, scientists have developed an "artificial tongue" that measures food spiciness using a milk protein.
Casein is the main protein in milk, and it binds with capsaicin, which is the chemical that gives chili peppers their hot and spicy flavor. When that binding action occurs in the mouth, the capsaicin is neutralized.
Led by Weijun Deng from the Shanghai Institute of Technology, a team of scientists set about replicating that action in a device that could be used to objectively gauge the spiciness of foods. Such a gadget could be utilized by people with very sensitive stomachs, or who lack the sense of taste – in the latter scenario, individuals could actually receive burns to the mouth if they unknowingly ate highly spicy foods.
The artificial tongue is in fact a rectangular slab of flexible gel made of acrylic acid, choline chloride and skim milk powder, which was cured via exposure to ultraviolet light. It's capable of conducting an electrical current.
When a substance containing capsaicin is placed on the gel, the casein in the milk powder binds with the chemical within 10 seconds, causing a decrease in the current that can easily be measured. The higher the levels of capsaicin, the greater the decrease.
Initial tests showed that the device is capable of detecting capsaicin concentrations ranging from below human detection to beyond levels perceived as painful. And in subsequent tests, which involved eight types of peppers and eight spicy foods, spiciness levels determined by the device fell in line with those determined by a panel of human taste testers.
Testing also showed that the artificial tongue is able to detect spicy chemicals other than capsaicin, such as those found in foods like ginger, black pepper, horseradish, garlic and onion.
A paper on the research was recently published in the journal ACS Sensors.
Source: American Chemical Society
