Flavor enhancers glutamic acid

In the food industries a number of amino acids have been widely used as flavor enhancers and flavor modifiers (see Flavors and spices). For example, monosodium L-glutamate is well-known as a meat flavor-enhancer and an enormous quantity of it is now used in various food appHcations (see Amino acids, L-MONOSODIUM glutamate (MSG)). Protein, hydroly2ed by acid or en2yme to be palatable, has been used for a long time in flavoring agents. 

The existence of protein receptors in the tongues of mice and cows have been shown. Monosodium L-glutamate MSG [142-47-2] is utilized as a food flavor enhancer in various seasonings and processed foods. D-Glutamate is tasteless. L-Aspartic acid salt has a weaker taste of umami. Glycine and L-alanine are slightly sweet. The relationship between taste and amino acid stmcture has been discussed (222). 

Change of taste behavior of acidic peptides may cause various changes of the taste of mixture in which acidic peptides are contained. When we attempt to utilize the ionic taste, we must carefully think about the behavior of acidic peptides. These studies of taste of acidic peptide should give us useful information about the role of aspartic and glutamic in flavor enhancing and in designing taste of foods or sodium ion diet. 

The production of a-amino acids by chemical synthesis yields a mixture of DL forms. The D-fomi of glutamic acid has no flavor-enhancing properties and thus requires transformation into the optically active form insofar as monosodium glutamate is concerned. The three methods for separating the optical isomers are (1) preferential inoculation method ... 

Glutamic Acid. MSG is an important flavor enhancer for natural and processed foods. It is also good for protecting the flavor and... 

A number of compounds have the ability to enhance or improve the flavor of foods. It has often been suggested that these compounds do not have a particular taste of their own. Evidence now suggests that there is a basic taste response to amino acids, especially glutamic acid. This taste is sometimes described by the word umami, derived from the Japanese for deliciousness (Kawamura and Kare 1987). It is suggested that a primary taste has the following characteristics ... 

Flavor enhancers are substances that carry the property of umami (see Chapter 7) and comprise glutamates and nucleotides. Glutamic acid is a component amino acid of proteins but also occurs in many protein-containing foods as free glutamic acid. In spite of their low protein content, many vegetables... 

Monosodium glutamate (MSG) is the sodium salt of glutamic acid. The flavor-enhancing property is not limited to MSG. Similar taste properties are found in the L-forms of q-amino dicarboxylates with four to seven carbon atoms. The intensity of flavor is related to the chemical structure of these compounds. Other amino acids that have similar taste properties are the salts of ibotenic acid, tricholomic acid, and L-thean-ine. 

Amino acid production by fermentation started around 1960 in Japan. Initially glutamic acid was the main product. It was sold as sodium salt, monosodium glutamate (MSG), a flavor enhancer on oriental cuisine. Other amino acids soon followed. They are used in food and feed to increase the efficiency of low protein substrates. Microbiologically produced enzymes were introduced around 1970. They are used in grain processing, sugar production, fruit juice clarification, and as detergent additives (Table 9.1). 

L-glutamic acid or its salt, monosodium glutamate (MSG), is used as an additive to human food to enhance the taste. Although seaweed had been used in Asia to enhance food flavor for over 1000 years, it was not... 

The simplest tastant, the hydrogen ion, is perceived as sour. Other simple ions, particularly sodium ion, are perceived as salty. The taste called umami is evoked by the amino acid glutamate, often encountered as the flavor enhancer monosodium glutamate (MSG). In contrast, tastants perceived as bitter or sweet are extremely diverse. Many bitter compounds are alkaloids or other plant products of which many are toxic. However, they do not have any common structural elements or other common properties. Carbohydrates such as glucose and sucrose are perceived as sweet, as are other compounds including some simple peptide derivatives, such as aspartame, and even some proteins. 

Glutamate is an abundant amino acid that is present in protein-rich foods as well as in the widely used flavor enhancer monosodium glutamate. This amino acid has a taste, termed umami, that is distinct from the other four basic tastes. 

Flavor enhancers are used imiversally in the food and pharmaceutical industries. Sugar, carboxylic acids (e.g., citric, malic, and tartaric), common salt (NaCl), amino acids, some amino acid derivatives (e.g., monosodium glutamate—MSG), and spices (e.g., peppers) are most often employed. Although extremely effective with proteins and vegetables, MSG has limited use in pharmaceuticals because it is not a sweetener. Citric acid is most frequently used to enhance taste performance of both liquid and solid pharmaceutical products, as well as a variety of foods. Other acidic agents, such as malic and tartaric acids, are also used for flavor enhancement. In oral liquids, these acids contribute unique and complex organoleptic effects, increasing overall flavor quality. Common salt provides similar effects at its taste threshold level in liquid pharmaceuticals. Vanilla, for example, has a delicate bland flavor, which is effectively enhanced by salt. 

Monosodium glutamate, the sodium salt of the amino acid L-glutamic acid, is used as a flavor enhancer in a variety of foods. Average individual daily intake in developed countries is 0.3-1.0 g/day. 

Monosodium glutamate (MSG) is a flavor enhancer. U.S. 2,877,160 (to Pfizer) and U.S. 2,978,384 (to Koichi Yamada) describe fermentation processes for glutamic acid. U.S. 5,907,059 (to Amylum Belgium A. E. Staley Manufacturing) describes recovery of the fermentation product and conversion to MSG. Estimate the cost of production via this route. 

Sodium glutamate (621) Monosodium L-glutamate (MSG) glutamic acid monosodium salt monohydrate Flavor enhancer ADI not specified ... 

Among the amino acids, L-glutamic acid can enhance or improve the flavor of foods. Glutamic acid is produced via fermentation directly from sugar using organisms such as Corvnebacterium glutamicum and Brevibacterium flavum.(66). 

Amino acid analysis is useful for assessment of the nutritional value of food and feed.15 The essential amino acids are methionine, cysteine, lysine, threonine, valine, isoleucine, leucine, phenylalanine, tyrosine, and tryptophan. Glutamic acid is a commercial flavor enhancer. Since amino acids are nonchro-mophoric (possess low UV absorbance), either pre-column or post-column derivatization is typically needed ... 

---