(1) Glutamic acid (GA) is one of the amino acids that are synthesized in human body. Since it can be self-synthesized, it is thus classified as one of the non-essential amino acids for human beings. GA often exists inside all kinds of animals and plants, and is found in a variety of different forms. The amidated GA is called glutamin (Gln) which is also an important amino acid in human body. Because of the characteristics of GA and its derivatives, they are widely used in medical therapies, nutritional supplements, feed additives, and plant growth supplements. In its molecular structure, GA has two carboxyl groups and one amino group. It is an amphoteric substance possessing both acidic and basic properties and it finds many uses in cosmetic and cleansing products, foods, and in other chemical manufacturing processes.
( 2) Molecular structure of GA (Molecular formula of GA: C5H9O4N)
APPLICATION OF GLUTAMIC ACID
I. Introduction
Glutamic acid have been the object of scientific study for over 150 years and have been sold as chemical products for the past eight decades. The application of glutamic acid can be broken down into four categories that include:
Research products and analytical standards
Comprised of glutamic acid and its derivatives, these compounds are used as reagents in biological and biochemical research, in biochemical processing and in automated and semi-automated analyzers used in chemical, medical and food industries. Glutamic acid reagents and derivatives are associated with protein synthesis techniques and with research in cell biology and biochemistry. Meanwhile, the food processing and pharmaceuticals industry also need appropriate analytical standards for amino acid assays of foods and medicines.
Medical/Pharmaceutical Application
Glutamic acid used as inputs for medical and pharmaceutical products will grow throughout the forecast period. These products include the most important enteral/parenteral nutrition solutions given to severely ill-hospitalized patients and neuractive drugs used as a vital nerve stimulant. A category of miscellaneous medical applications consisting of specialized diets for people with metabolic disorders and drugs designed to dissolve mucous in the lungs.
Flavor enhancer and human dietary supplement
The fraction of total amino acid value represented by food grade glutamic acid is shrinking during the past three years. This product will continue to decline in value in the future.
Chemical Intermediate
This product group is composed of amino acid compounds destined to become drugs, polymers and other chemical products.
II. Research Products and Analytical Standards
Glutamic acid and its derivatives have been used in basic chemical research for the past 150 years. Even so, their applications have not been noted in chemical encyclopedias published as recently as a few years ago. The commercial significance of their use, especially on medicine and biochemical processing, has only emerged during the past ten to twenty years. The current situation represents a significant change, and the changes were brought about by developments in several branches of science and technology. The combined effect of progress in genetic engineering, biopolymers, and protein engineering has fueled the demand for purified glutamic acid and their derivatives.
TABLE 1 - MAJOR USES OF GLUTAMIC ACID AND ITS DERIVATIVES IN RESEARCH
| PROTEIN ENGINEERING |
Peptide synthesis Protein modification Polymer supports |
| BIOCHEMICAL/CELL BIOLOGY |
Biochemical experiments Cell biology research |
| ANALYTICAL APPLICATIONS |
Analytical standards Diagnostic products and procedures |
IV. Flavor enhancer and human dietary supplement
Monosodium glutamate (MSG), the single largest amino acid product, has been used as a flavor enhancer throughout the world for the past forty years. MSG is used worldwide in huge quantities as a flavor enhancer in foods. In Western countries, MSG is used as domestic flavor enhancer. In Japan, on the other hand, MSG is marketed only to the food processing industries, while MSG mixtures with 1.5-8.0% disodium 5'-ribonucleotides have gained a wider domestic market.
Amino acid diet supplements have arisen as an outgrowth of several technological developments. Glutamic acid can easily lose its amino (NH2-) group and thus participates in the transamination process. Also, glutamic acid is the precursor of gamma-amino butyric acid (GABA), a chemical associated with nervous system function.
V. Chemical Intermediate
One of the fastest-growing markets for glutamic acid is that for chemical intermediates. These products are distinguished from inputs of other product, such as cell culture media, where the amino acids are consumed as part of the product's use. Chemical intermediates are products that are used to make other chemical products. The example of product using glutamic acid as intermediate is glutathione, one kind of liver drug.
MEDICAL AND NUTRITION SUPPLEMENTARY APPLICTIONS
There is abundant GA in human blood and organs. Other than serving as a raw material in protein syntheses, it is also involved in the transmittance of central nervous system. Gln is responsible for nitrogen transportation about human body and serves as the main source of energy to several kinds of cells. It is due to the fact that GA is directly involved in the metabolic Krebs cycle (TCA cycle) that GA plays an indispensable role in human body metabolism.
Therefore, GA has been employed in treatments of disorders of nervous system such as epilepsy, added to dietary supplements for post-operation patients, and wholesome intravenous feeding nutritive solutions, which has also been used extensively lately for minimizing post-surgery infections and strengthening patient's immunity such as the activation of T-cells. There has been tremendous progress in the physiological studies of various peptides and proteins synthesized with GA as one of their main components. Those peptide and proteins are used not only in dietary supplements, but also, such as in the case of glutathion, made into part of synthetic antibiotics and other pharmaceuticals for human health cares.
FEED APPLICATIONS
GA and Gln are just as important to animals physiologically as they are to human beings. For instance, chicken would stop growing if there is severe deficiency in GA alone. GA is quite often blended into commercial chicken feed in the form of MSG.
FOOD AND FRAGRANT ESSENCE APPLICATIONS
The amino group in GA can easily undergo Maillard reaction with reducing sugars possessing a carbonyl group, and thereby to form fragrant compounds. With various sugars, it can be made into all kinds of different fragrant ingredients that are eatable and light in color and thus suitable for adding into food without spoiling the appearance of food products. It is therefore widely used in food processing industry.
APPLICATIONS TO CULTURE MEDIUM FOR MICROORGANISM CULTIVATION
GA happens to be one of the main components in the cell wall of Gram-positive bacteria. It is also one of the more essential amino acids for other microorganisms to grow on. In most cases, it is often necessary to add GA into culture media to effect normal growth.
AGRICULTURAL APPLICATIONS
GA is one of the major amino acids in plant proteins and Gln plays a role of the major nitrogen storage for plants. That is why GA is often one of the more prominent ingredients in many plant growth supplements. Besides, since GA is vital in the nitrogen metabolism in plants, it can be somewhat modified purposely to cut down on its capability to form Gln by combining with ammonia, and the accumulation of ammonia inside the plant can result in premature death of the organism. Therefore, this modification can be utilized as a measure to kill weeds.
CHEMICAL PRODUCT APPLICATIONS
Surfactants and buffers:
GA is an amphoteric substance that contains both acidic and basic functional groups and thus a natural buffer by itself. It is hydrophilic by nature and can combine with hydrophobic fatty acids easily to form molecules with both water-soluble and water repelling portions that can be used as surfactants. There are many applications of GA derivatives as surfactants, especially due to its lack of harmful effects to skin and their general smooth appearance, it is very much favored by cosmetic, moist containing and hair shampooing product manufacturers. The amino acid when used with other organic acids can also be made into precursors of superconductors such as yttrium, barium and copper salts of organic acids.
Gelatinizers:
The surfactants made by combining GA and various fatty acids can further react with compounds with ammonium group to result in some emulsifiers, which is very useful especially in recovering process of spilt oil in cases of petroleum pollution accidents.
Hardeners:
Some derivatives of GA can be made into hardeners such as the one for epoxy resins by enhancing the adhesive force of the resin.
Chelating agents:
GA has two carboxylic groups, which can form chelates with many metal cations. Such chelating reaction is useful in the removal of heavy-metal contaminants in the wastewater treatment processes.
APPLICATIONS OF GA IN NON-FOOD PRODUCT FIELDS
I. The uses of reagent grade GA
Reagents employed in research and analytical standards Mainly in research work of biochemistry, bioassays, and protein syntheses
Medical therapies and pharmaceuticals Nutritive supplements through enteral or parenteral routes, i.v. solutions, and drugs for metabolic disorders, hypertension, neuroregulating cases, and ophthalmic solutions
Raw material for chemical synthetic process Synthetic drugs, agricultural chemicals, surfactants, and other chemicals
Ingredients for cosmetic products Ultraviolet light block, moisturizer, nutritive additives in shampoos and the like
II. Forms of GA products: GA crystals, crystalline MSG, GA-HCl crystals or solution, and other salt forms of GA
III. Other applications of MSG
Feed additive It will lift the appetite of piglets, enhance their consumption of food and increase the growth rate of the animal.
Plant growth supplements
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