Amino acids
These are a group of water-soluble organic compounds having a carboxyl (–COOH) and an amino (–NH2) group attached to the same carbon atom, known as the α-carbon atom. The general formula is R–CH(NH2)COOH, where R may be hydrogen or an organic group. Amino acids join together through the formation of peptide bonds (brought about by a reaction between adjacent carboxyl and amino groups, with the elimination of water), to form short chains (peptides) or much longer chains (polypeptides).
Plants and many micro-organisms can synthesize amino acids from simple inorganic compounds, but animals rely on adequate supplies in their diet. The essential amino acids must be present in the diet; man requires ten: arginine, histidine, lysine, threonine, methionine, isoleucine, leucine, valine, phenylalanine, and tryptophan. Other amino acids can be manufactured from these.
Carbohydrates
Organic compounds having the general formula Cx(H2O)y. They range in complexity from monosaccharides of relatively low molecular weight e.g. the simple sugar glucose, to polysaccharides of large molecular weight e.g. cellulose, starch and lignin. They serve in the storage of food and its conversion to energy in living organisms and in forming supporting structures in plants.
Enzymes
(Ger. Enzym, from mod. Gk. enzumos ‘leavened’). Enzymes are proteins found only in trace amounts in cells, production being controlled by the cell's genes. They act as catalysts for specific biochemical reactions, and require specific reaction conditions such as concentration, temperature and acidity. Most enzymes have names based on that of the substrate on which they act, and end in -ase. E.g. maltase is the enzyme which acts to break down maltose.
Gluten
A polymer resulting from the hydration and cross-linking of the proteins glutenin and gliadin which are naturally present in wheat in approximately equal amounts. The gluten and other proteins create a filled three-dimensional network or foam structure (this has also been described as an 'infinite periodic minimal surface') which permeates the dough during its development. It functions to prevent the carbon dioxide from escaping, so enabling the dough to expand. Its production and development are stimulated by fermentation, kneading, and respiration of the yeast. The gluten proteins represent up to 90% of the protein content of white flour.
Hydrolysis
The chemical decomposition of a substance by water, the water also being decomposed. The reaction is of the general type:
Proteins
Proteins are essential to all living cells, and are made up from various proportions of at least 20 different amino acids. Some also contain sulphur, others phosphorus. The particular sequence of the amino acids in the protein polypeptides (see under Amino acids ) is known as their 'primary structure'. The polypeptides may also be coiled or folded, the resulting shape being known as their 'secondary structure'. The 'tertiary structure' denotes their three-dimensional shape. The 'quaternery structure' denotes the relationship of the component polypeptides in three dimensions. These features determine the properties of the protein and hence its biological role. They can have molecular weights of up to several million.
Starch
A polysaccharide consisting of the glucose polymers amylose and amylopectin. Wheat starch contains about 23% amylose which consists of unbranched glucose chains; amylopectin consists of highly branched short glucose chains. Their different forms account for the need for both α-amylase and β-amylase in the diastasis process.
Vitamins
From 'vital amines' (when it was discovered that some vitamins do not contain amines, the 'e' was dropped from the name). Vitamins are organic compounds, generally classified as water-soluble or fat-soluble. They are required by living organisms for normal health and function as coenzymes (nonprotein molecules that associate whith enzymes) or coenzyme precursors.