Discovery of new taste receptor for high-protein foods
us to taste the flavour found in high-protein food. The receptor
for amino acids, which make up proteins, causes the umami taste
found in meat and other protein-rich foods, which is often enhanced
by additives. The discovery could lead to the design of new
additives.
Researchers in California have discovered the receptor that allows us to taste the flavour found in high-protein food. The receptor for amino acids, which make up proteins, causes the umami taste found in meat and other protein-rich foods, which is often enhanced by additives. The discovery could lead to the design of new additives, according to Nature news.
The research published in the Nature advance online publication shows that in mice the receptor responds to nearly all of the 20 amino acids found in proteins. The human version of the receptor is most sensitive to the chemical glutamate.
Glutamate is one of the most common amino acids in our diets, and gives high-protein food its meaty, umami flavour. It has been estimated that around 1.5 million tons of monosodium glutamate is used annually to make food taste good.
The study leader, Charles Zuker of the University of California, said that the more specialised receptor in humans need not be a disadvantage, or reflect differing diets, and could merely be the result of evolution.
Bernd Lindemann, a taste researcher at Saarland University in Germany explained that the ability to taste amino acids "guides us to proteins", which themselves have no taste.
The Nature news report highlights some problem areas in the research. A different research group discovered an umami receptor two years ago and it is not known whether this is a real receptor, as mice lacking that receptor can still taste umami.
There are two molecules in the new receptor, T1R1 and T1R3, and T1R3 is also found in a sweet-taste receptor, along with another molecule T1R2.
Researchers believe that different species and individuals show variation in the receptor gene, causing different preferences for taste. Zuker said: "I'd bet that human taste preferences - whether you have a sweet tooth or not, say - are down to nothing but differences in receptor repertoire. We are starting to translate behaviour into simple genetic differences."
The California team experimented on isolated receptor-bearing tastebud cells and they plan to follow up their research with finding out what messages these cells send to the brain, and what the brain does with this information.
"We don't know how the brain determines the final taste of an amino acid," said Nicholas Ryba of the National Institute of Dental and Craniofacial Research in Maryland, who participated in the research. "I've tasted every single amino acid. Not all of them taste umami," he added.
With the US market for artificial sweeteners thought to be worth more than $600 million (€694.72m) each year, the research could provide endless potential for flavour manufacturers.
