Amino acids are relatively simple molecules that have both amino (NH2) and carboxyl (COOH) functional groups. Amino acids have existed from ancient times along with carbohydrates, fatty acids, and basic nutrition from an evolutionary perspective. Twenty amino acids are minimal for growth, nitrogen balance, maintenance of host defense, nervous system (Fernstrom, 2000; Young et al., 1994) and muscle function, and gene expression regulation (Fafournoux et al., 2000) It is a necessary ingredient. Amino acid catabolism is a source of energy through the intermediate products of the glycolytic pathway and the citric acid cycle. However, a large amount of amino acids cannot be stored in the body, and all tissues and organs must function in an integrated manner to maintain homeostasis. Thus, amino acid requirements have a significant health impact (Rose, 1957; Millward, 1994; Young, 1998; Young and Borongha, 2000). Nine amino acids are thought to be essential in everyday diets, but they are subject to age (Baertl et al., 1974; Schober et al., 1989), nutritional status (Kurpad et al., 2003), and great stress. Being exposed to behavioral psychological effects such as exposure (Lacey and Wilmore, 1990; Obed et al., 2002) has made the boundary of whether it is essential or not. In fact, the 2007 WHO / FAO / UNU Expert Meeting Report on “Neutral Needs for Human Nutrition” reflects a shift to recent research on the quality of food-provided proteins The need for almost all essential amino acids has increased significantly.

Amino acids are the biochemical building blocks of proteins (large and naturally occurring polypeptides). Protein chains are made by linking an amino group of one amino acid to another carboxyl group. Amino acids absorbed by the body are used to reconstitute the body’s own proteins. Therefore, amino acids must be present in a sufficient amount and in proper balance as a protein substrate. The history of amino acid discovery began in 1806 when asparagine was separated from an extract of asparagus sprout and continued until the discovery of threonine in 1935. For industrial production, the glutamic acid used as a seasoning dates back to 1909, when it was extracted from wheat gluten hydrolyzate. In the 1950s, advances in purification and separation techniques expanded the use of many amino acids, especially those produced by fermentation. Currently, four production methods are used: extraction, fermentation, enzymatic method, and chemical synthesis.

Since 1956, crystalline amino acids have been used in the medical and pharmaceutical fields as parenteral components and later as nutrients by enteral nutrition. For example, high-quality amino acids are used as nutritional therapy in the treatment of inflammatory bowel disease, Crohn’s disease, and food allergies. Certain amino acids are used as ACE inhibitors, HIV protease inhibitors, antiviral drugs, and antidiabetic drugs.

In many developed countries, amino acids have long been used as a major component of dietary supplements and cosmetics by healthy individuals as a nutritional supplement during sports, to maintain cardiovascular health, and as a hematopoietic agent.