Gustation can be defined as the act of tasting. There are 5 major tastes that human tongue can recognise excluding fatty as a taste. The energy quality of the taste become electrical signal that carries information to the brain about the substance on the tongue is known as taste transduction. There is more information to learn and understand by studying gustatory system.
The carboxylate anions of glutamic acids (Molecular Weight: 147.12926 g/mol) produce a sensation on the tongue that different to sweetness, sourness, saltiness and bitterness. this sensation is known as umami or savoriness.Umami taste was identified by Kikunae Ikeda at imperial university of Tokyo.
Glutamic Acid (IUPAC-2-aminopentanedioic acid,Molecular Weight:147.13g/mol)
Monosodium Glutamate (MSG)(IUPAC-Sodium 2-aminopentanedioate,Molecular Weight:169.111 g/mol)
MSG is the sodium salt of glutamic acid that used in gastronomy, provides the same sensation as umami does.
Thermal taste and Umami
By heating and cooling our tongue, sensations that we sense provide equivalences for major tastes sensations. Such as, around 35’C heat can bring the sweet sensation to tip of your tongue. Most of the experiments today shows that intensity of the sensation of sweetness is consecutively proportional to the heat while sourness and saltiness inversely proportional to heat.
If you think profoundly through these phenomena there will be many questions to question. As a start, what would we taste, if 35’C monosodium glutamate placed tip of the tongue??
(Special thanks to http://pubchem.ncbi.nlm.nih.gov/ for pictures of the molecular structures)