Fire in your mouth? Contrary to popular belief, the burning sensation you experience from a spicy chili pepper isn’t actually tasting “heat”. It’s a clever illusion perpetrated by a molecule called capsaicin. It belongs to a class of molecules called capsaicinoids which are the compounds found in members of the capsicum family (also known as peppers). The most common capsaicinoid is capsaicin that gives hot chile peppers the heat you experience when eating them.
How do we perceive the taste of capsaicin?
Capsaicin doesn’t actually activate our taste buds for the five basic tastes (sweet, sour, salty, bitter, umami). It interacts with sensory neurons in our mouth and throat, triggering a response known as chemesthesis. This is the sense involved in detecting irritants or chemicals, like the sting of wasabi or the minty coolness of menthol.
These specialized sensory neurons have TRPV1 receptors on their surface. TRPV1’s natural function is to detect hot temperatures. When capsaicin binds to TRPV1, it mimics the effect of heat, essentially sending a false alarm signal to the brain.
Brain Misinterpretation?
The brain interprets the TRPV1 receptor activation as intense heat. This triggers the burning sensation we associate with spicy food, even though there’s no actual rise in temperature. Scientists believe it’s a clever evolutionary defense mechanism. Capsaicin deters herbivores from munching on the peppers, allowing them to reproduce and spread their seeds.
Why does the burning continue so long?
The burning doesn’t stop right after you swallow the chili. There are two main reasons why the spiciness of food can linger after the first bite:
- Sticky Nature: Capsaicin is a hydrophobic molecule, meaning it dislikes water. This characteristic makes it cling to the mucous membranes in your mouth and throat, where the TRPV1 receptors it targets reside. Unlike water-soluble food components that get washed away with saliva, capsaicin hangs around for a while, continuing to activate TRPV1 receptors and sending the “heat” signal to your brain.
- Gradual Breakdown: While some of the “taste” gets washed away with saliva, it doesn’t dissolve instantly. Enzymes in your saliva slowly break down molecules. This breakdown process can take time, meaning new capsaicin molecules might still be activating TRPV1 receptors even after you’ve swallowed the first bite, contributing to the lingering burning sensation.
Does capsaicin has a taste?
Technically, no. We don’t have taste receptors specifically for capsaicin or spiciness. The burning sensation is a result of the nervous system response triggered by capsaicin on TRPV1 receptors. However, taste and chemesthesis can work together. The flavor compounds in chili peppers can be detected by taste buds, adding another layer of complexity to the overall experience of eating spicy food.
