AMINO ACIDS

使用

Amino Acids is the food additive amino acids may be safely used as nutrients added to foods. the food additive consists of one or more of the following individual amino acids in the free, hydrated, or anhydrous form or as the hydrochloride, sodium, or potassium salts: l-alanine, l-arginine, l-asparagine, l-aspartic acid, l-cysteine, l-cys- tine, l-glutamic acid, l-glutamine, aminoacetic acid (glycine), l-his- tidine, l-isoleucine, l-leucine, l-lysine, dl-methionine (not for infant foods), l-methionine, l-phenylalanine, l-proline, l-serine, l-threo- nine, l-tryptophan, l-tyrosine, or l-valine. the additive(s) is used to significantly improve the biological quality of the total protein in a food containing naturally occurring, primarily intact protein that is considered a significant dietary protein source. the amount of the additive added for nutritive purposes plus the amount naturally present in free and combined (as protein) form should not exceed the levels of amino acids expressed as percent by weight of the total protein of the finished food.

定義

Derivatives of carboxylic acids in which a hydrogen atom in an aliphatic acid has been replaced by an amino group. Thus, from ethanoic acid, the amino acid 2- aminoethanoic acid (glycine) is formed. All are white, crystalline, soluble in water (but not in alcohol), and with the sole exception of the simplest member, all are optically active. In the body the various proteins are assembled from the necessary amino acids and it is important therefore that all the amino acids should be present in sufficient quantities. In humans, twelve of the twenty amino acids can be synthesized by the body itself. Since these are not required in the diet they are known as nonessential amino acids. The remaining eight cannot be synthesized by the body and have to be supplied in the diet. They are known as essential amino acids.
The amino acids that occur in proteins all have the –NH₂ group and the –COOH group attached to the same carbon atom. They are thus alpha amino acids, the carbon atom being the alpha carbon.

农业用途

Proteins, which constitute around 50% of the dry weight of living matter, are essential constituents of all living cells. These are polymers composed of simple monomers called a-amino acids, linked by peptide linkages.
Autotrophic organisms, principally green plants, synthesize amino acids. The simplest naturally occurring amino acid is glycine (H₂NCH₂COOH). About 20 commonly occurring amino acids have been identified as building blocks of most plant and animal proteins.
Amino acids are linked by peptide bonds formed between the carboxyl group of the first amino acid and the amino group of the second amino acid. Many such amino acid molecules join together to form peptide linkages and hence the polypeptide. The sequence of these amino acids in the polypeptide determines the shape and structure of proteins and their properties and biological role.