Writing in the Journal of Clinical Investigation, scientist Philippe Besnard and his team from the University of Burgundy identified receptors, called CD 36, in the tongues of rodents. It is not known yet if this discovery is applicable to human tongues as well.
Experts have conventionally thought that the tongue detects five tastes - sweet, salty, sour, bitter and the savoury umami taste - but this discovery could changed the way ingredients are formulated.
For example, the salty taste is physically unique. It was recently discovered that taste receptors inside the human tongue require the shape and size of the sodium ion in order to register a salty taste, thus influencing the development of salt replacers.
In the same way therefore, the possible identification of a fat taste bud in humans - the next logical step - could help food makers develop products that satisfy consumer craving for the creamy mouthfeel and flavour that fat can give.
This would be of great interest to food makers looking to tap in on growing concerns about obesity and weight gain. In the west, about 40 per cent of all energy comes from fat consumption.
"As we gain more information regarding the function of this receptor, we may be able to devise better strategies to address the addictive potential of dietary fat," said professor Nada Abumrad of Washington University School of Medicine, writing in the in the same medical journal.
This remains to be seen however. The CD36 receptor is already known to exist in many tissues involved in fat storage, but its taste function, if it exists in humans, has not been studied.But the University of Burgundy study still represents an important breakthrough.
By knocking out the receptor in some mice so that it no longer worked, the team was able to compare the behaviour of normal mice and these 'knock out' mice.
According to Besnard, the normal rodents showed a preference for fatty foods when offered them, yet the knock out mice did not. In addition, when the researchers put a fatty liquid onto the tongues of the normal rats, this triggered a release of fat-processing substances from the digestive organs.
This reaction did not happen in the knock out mice.
Previous research into taste has revealed that the human tongue has about 10,000 taste buds with five taste sensations: sweet, bitter, and umami, which work with a signal through a G-protein coupled receptor; salty and sour which work with ion channels.
Contrary to popular understanding, taste is not experienced on different parts of the tongue. Though there are small differences in sensation, which can be measured with highly specific instruments, all taste buds, essentially clusters of 50 to 100 cells, can respond to all types of taste.
Taste buds (or lingual papillae) are small structures on the upper surface of the tongue that provide information about the taste of food being eaten.