"Although other receptors have been found on the tongue that are also aroused by glutamate, they are not specific. That is, they need to be in contact with nucleotides and many other amino acids to be activated.
Our study reveals the first receptor on the tongue exclusively for glutamate," Ana San Gabriel, the main author of the article and a scientist belonging to the Spanish Network of Researchers Abroad, based at the Institute of Life Sciences in Ajinomoto, Kawasaki (Japan), explained to SINC.
According to the study, which was published in the latest issue of the American Journal of Clinical Nutrition, glutamate is a non essential amino acid that is used commercially as glutamate sodium salt, monosodium glutamate (MSG) E-621, because it is stable and easy to dissolve. This added glutamate, identical to the 'natural glutamate', is sometimes used to reduce cooking and meal preparation time and to provide more flavour.
MSG is also used to reduce the sodium in meals: table salt contains 40% sodium, whereas MSG contains 13%. Many fermented or ripe foods are rich in natural MSG, such as ripe tomatoes (250-300 mg/100g), parmesan cheese (1600 mg/100g), Roquefort cheese (1600 mg/100g) and Gouda cheese (580 mg/100g). Manchego cheese and Iberian cured ham have a similar taste.
One hundred years ago, Kikunae Ikeda, a lecturer at the Imperial University of Tokyo, discovered the flavouring properties of glutamate after extracting it from the seaweed Laminaria japonica, calling its taste 'umami' (savoury). Since then, MSG has been one of the condiments that has received the most attention from researchers, along with its effects. All the international food safety agencies consider it safe for human consumption.
Regarding whether glutamate is possibly toxic, the researcher is categorical. "If food safety is evaluated with scientific rigor, MSG is entirely safe for human consumption. If people talk about it being toxic and MSG continues to receive negative publicity, it is because results are extrapolated from administration routes and doses that do not correspond to reality. In fact, it is less toxic than salt".
Even in breast milk
We are exposed to free glutamate from childhood. The most abundant amino acid in breast milk has 0.02% of glutamate, so a 5kg baby who takes 800 ml of breast milk a day, consumes 0.16g of glutamate. "The amount of glutamate consumed by babies that only breastfeed is equivalent to the MSG of Korea or Taiwan," the researcher concludes.
Total consumption of glutamate (both free and joined to proteins) in an adult diet amounts to around 10 grams a day (100-150mg/kg/day assuming a weight of 70kg), whereas the consumption of glutamate as a condiment in the form of MSG varies from 0.4g in the US, 1.5g in Japan and Korea and 3g in Taiwan (from 6 to 43mg/kg/day). MSG consumption in Spain has not been estimated, but the United Kingdom is calculated to consume 0.6 g on average and 2g in a minority segment of the population (three times more than average).References:
SINC | EurekAlert!
Cryo-electron microscopy achieves unprecedented resolution using new computational methods
24.03.2017 | DOE/Lawrence Berkeley National Laboratory
How cheetahs stay fit and healthy
24.03.2017 | Forschungsverbund Berlin e.V.
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy