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The basic tastes are fundamental flavour sensations that form the foundation of our gustatory experience. Traditionally, there are five primary basic tastes:
Sweet: Often associated with sugars, this taste is perceived as pleasurable and is commonly found in sugary foods, fruits and some vegetables.
Sour: This taste is characteristic of acidic substances. Sour flavours are typically found in citrus fruits, vinegar and fermented foods.
Salty: Associated with the taste of salt, this flavour enhances the flavour of other tastes. Common sources include table salt and salty snacks.
Bitter: Often detected in substances like coffee, dark chocolate and certain vegetables, bitterness is an acquired taste and is sometimes associated with potential toxins in nature.
Umami: This taste is described as savoury and is found in foods rich in glutamate, such as meat, broth, mushrooms and certain cheeses. Umami also enhances the overall flavour of dishes.
While these five basic tastes have long been recognized, there is ongoing research exploring the possibility of additional basic tastes. The idea of a potential sixth taste has recently been the topic of interest among scientists.
The proposed sixth taste is Ammonium Chloride (NH4Cl) which will join the likes of the five basic tastes.
Ammonium chloride presents a unique flavour profile, distinct from other tastes. It elicits a robust response from our receptors attuned to sour flavours, often indicative of spoiled food, suggesting a potential survival mechanism. Avoiding the consumption of spoiled meat or fish, potentially laden with harmful bacteria, would be facilitated by this taste detection.
Found notably in “salmiak,” a salt licorice confection popular in northern Europe, ammonium chloride is a mildly toxic chemical. The ability of a species to detect and react to its taste is postulated as a survival adaptation, making it a stellar basic taste candidate.
How does the sense of taste protect us?
The sense of taste plays a crucial role in human function. Taste buds not only facilitate the way we enjoy flavours and food but also serves as a defence mechanism by helping us detect toxins. When taste receptors are activated, they communicate with the brain, helping us discern the quality and safety of food. Despite the visual appeal of certain foods, our taste buds can identify potential toxicity, steering us away from consuming harmful substances. Ammonium, known for its toxicity, triggers an aversion in many of us, thus our taste buds act as a deterrent against ingesting waste or harmful substances. However, in specific cultural contexts, such as Scandinavia, ammonium chloride is embraced for its taste, featuring in salty licorice.
How does ammonium chloride tickle our taste buds?
In a recent study, researchers explained that ammonium chloride activates a specific proton channel, OTOP1, in our sour taste receptor cells, meeting a key criterion for primary taste. The study found that ammonium chloride significantly activates OTOP1 compared to other acids. This research marks the first comprehensive investigation into how our taste buds respond to ammonium chloride. Both human and mouse OTOP1 channels displayed similar responses to ammonium chloride, akin to reactions to acid. The study concludes that OTOP1 receptors are crucial for humans to detect the taste of ammonium chloride, suggesting the existence of a new taste receptor.
The bottom line —
Recent research has identified a new novel taste response in humans, expanding the traditional five tastes—sweet, sour, salty, bitter, and umami. Ammonium chloride triggers a distinct sensation, described as “bitter, salty, and slightly sour” in our taste receptors. While there may be other tastes and flavours yet undiscovered, our biological makeup likely already encompasses them. For now, ammonium chloride is the newest taste on the block!
