Flavour Pupils
German scientists were curious to find out exactly where that bitter aftertaste came from and looked into it. They studied the receptors on the human tongue. On our tongue, there is one type of receptor for perceiving sweet and 25 types of receptors for perceiving bitter. Two of them are responsible for noticing the bitter taste of stevia extract.
Glucose molecules
The researchers also found out how these receptors reacted to different stevia concentrations. For example, they found that the structure of glycosides - a compound found in plants - determines how sweet or how bitter stevia is. "If a molecule has more glucose molecules attached to it, it is sweeter and less bitter," concluded the researchers. For example, a molecule with five glucose molecules turns out to be five times sweeter and two thirds less bitter than a molecule with only two glucose molecules.
Beyond the screens, we are working together with the producer to look for an improved taste of stevia in the future.