Umami

Umami (Japanese旨 味, dt " meaty and hearty, savory " ) applies in addition to sweet, sour, salty and bitter as the fifth sense of taste and quality is the name given to a full-bodied taste. Is caused to the umami taste by the amino acid glutamic acid, which is found naturally in small amounts in protein food such as meat, cheese, tomatoes and mushrooms. Artificially inflicted Umami is mainly used in Asian cuisine and in the industrial production of convenience food ( soups, prepared foods ). However, Umami enhances certain flavors in its intensity, is also able to superimpose possible errors taste of food and correct. The world market for man-made monosodium L- glutamate (MSG ) in 2009 was about 2 million tons, which are mainly produced in Japan.

History

Be first Japanese researcher Ikeda Kikunae described in 1908 umami taste quality. In his experiments, Ikeda found that there is a taste quality off the usual division into sweet, sour, salty and bitter, indicating especially high protein foods.

Properties

As in Western culture as a separate Umami taste is still mostly unknown, one can also briefly described as savory or intensively him. However, Umami not restricted to savory dishes.

The support of the umami taste is free, leached out by proteolysis of the proteins amino acid glutamic acid. It forms the physiologically relevant water-soluble glutamate zwitterion. Its salts are known as glutamates. The sodium cation of sodium glutamate ( properly monosodium L-glutamate monohydrate, engl. Monosodium glutamate, MSG) dissociates in aqueous fluids of the glutamic acid. Glutamic acid are present in all protein-containing foods. The release of glutamate through cracks in the cell membranes is enhanced by cooking, drying or fermenting.

Particularly plentiful are Glutamate in ripe tomatoes, meat, shiitake, cheese (particularly parmesan ), condiments (eg, soy sauce, fish sauce, broth, stock, meat extract, yeast extract, Maggi seasoning, celery seed ), and present in human breast milk. A particular use is glutamic acid in the food industry where they biotechnologically produced is used as a flavor enhancer. The term flavor enhancers should be understood in this context as the utilization of the available physiological taste spectrum.

Biochemistry

In addition to glutamic acid also show 5'- ribonucleotides of purines such as 5' - inosinate ( used mainly in meat), 5'- guanylate ( used mainly in plants) and 5'- adenylate ( used mainly in fish and shellfish ) umami flavor. In addition, the intensity of the umami taste of glutamic acid by inosine monophosphate (IMP ) and guanosine monophosphate ( GMP) is greatly enhanced. Since the induced by purine nucleotides and glutamates umami sensations are complementary, they are often used together.

The metabotropic glutamate receptor mGluR4 mediates together with the receptors T1R1 and T1R3 umami. The latter is, as with the receptors for sweet taste quality to G- protein-coupled receptors of the class C (C- GPCR). In these receptors, called a Venus flytrap domain ( venus flytrap, VFT domain) is bound to a transmembrane domain.

Side effects

The monosodium glutamate stood since 1969 suspected cause in higher doses, side effects, such as headaches or pain in the limbs, the so-called Chinese restaurant syndrome. However, could not be detected in previous studies that the diet additionally supplied Glutamate can cause the described symptoms.