casein

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Related to Caseins: Sodium caseinate, casein milk

casein

(kā`sēn), well-defined group of proteins found in milk, constituting about 80% of the proteins in cow's milk, but only 40% in human milk. Casein is a remarkably efficient nutrient, supplying not only essential amino acids, but also some carbohydrates and the inorganic elements calcium and phosphorus. The calcium caseinates form an insoluble white curd when acidified by hydrochloric acid or sulfuric acid, or when milk is soured by bacterial contaminants. Acid casein is used widely in cheese, adhesives, water paints, for coating paper, and in printing textiles and wallpaper. In neutral solutions the enzyme rennin converts one of the caseins to an insoluble curd; most of the protein in cheese is rennetrennet,
substance containing rennin, an enzyme having the property of clotting, or curdling, milk. It is used in the making of cheese and junket. Rennet is obtained from the stomachs of young mammals living on milk, especially from the inner lining of the fourth, or true,
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 casein curd. When treated with formaldehyde the curd forms casein plastic, used for manufacturing imitation tortoiseshell, jade, and lapis lazuli.

Casein

 

a complex phosphoprotein that is formed from its precursor caseinogen as a result of the splitting of peptide bonds in the process of milk curdling. Casein is readily soluble in saline solutions in neutral or alkaline media, and it precipitates when acidified. Its molecular weight is 75, 000–100, 000.

Casein is a heterogeneous protein; by physical and chemical methods it can be divided into three fractions that are similar to one another in amino-acid composition, (α-casein β-casein, and γ-casein). Dried casein is a tasteless and odorless white powder. Casein is the principal protein component of milk and milk products. Cow’s milk contains 2.8–3.5 percent casein; human milk, 0.3–0.9 percent. This most important dietary protein contains a complete complement of the essential amino acids; it contains especially high percentages of methionine (~3.5 percent), lysine (˜6.9 percent), tryptophan (~ 1.8 percent), leucine (˜12.1 percent), and valine (7.0 percent). The stomachs of mammals shortly after birth contain the enzyme chymosin, or rennin, which curdles milk (this can also be catalyzed by other proteolytic enzymes). In industry casein is used in the manufacture of paints, glues, synthetic fibers, and plastics.

I. B. ZBARSKII

casein

[′ka‚sēn]
(organic chemistry)
The protein of milk; a white solid soluble in acids.

casein

A protein; the chief nitrogenous ingredient of milk.

casein

a phosphoprotein, precipitated from milk by the action of rennin, forming the basis of cheese: used in the manufacture of plastics and adhesives
References in periodicals archive ?
Besides using transglutaminase in traditional dairy products, efforts to prepare novel dairy ingredients, such as caseins or caseinates, with tailor-made stability and functionality through the enzymatic cross-linking of milk proteins, are currently underway at NIZO food research.
Milk proteins especially caseins and lactoserum (whey) proteins are nutritionally very important because these proteins contain all essential aminoacids in optimal amounts and are the most vital source of bioactive peptides(Cozma et al., 2011).Whey, a by-product from the curd and cheese manufacturing, was once considered a waste product(Pelmus et al., 2012).
Smaller micelles of casein (without the effect of [[alpha].sub.s]-CN and [kappa]-CN) exhibited favorable effect on dry matter cheese yield.
Thermal denaturation of whey proteins in mixtures with caseins studied by differential scanning calorimetry.
In this experiment, the potential effect of nanoemulsified methionine and cysteine on milk protein casein expression in bovine epithelial mammary cells was studied.
The substantial variation among different milk species was observed regarding major protein fractions like crude protein (CP), true proteins (TP), caseins and whey proteins; and the nitrogen components such as NCN and NPN contents.
The calcium ions chelating agents, including trisodium citrate (TSC), ethylene diamine tetraacetic acid, and sodium phosphates, were found to disrupt the casein micelles in milk [26-29].
Khorchani et al., "Identification of bioactive peptides derived from caseins, glycosylation-dependent cell adhesion molecule-1 (GlyCAM-1), and peptidoglycan recognition protein-1 (PGRP-1) in fermented camel milk," International Dairy Journal, vol.
Electrophoretic Analysis (Tricine-SDS-PAGE) of Bovine Caseins. Acta Farm Bonaerense 2002; 21(1): 57-60.
Further, the report states that whey proteins are increasingly preferred as casein proteins have a low percentage of branched amino acids and are slow digesting.
In addition, human milk contains primarily whey proteins, whereas cow's milk has about 80% of its protein as casein. Finally, goats and yaks only produce A2 caseins, and most sheep milk is A2.
Casein markets include: ready-to-drink nutritional beverages, sports nutrition powders, protein bars, yogurts, processed cheeses and chocolates and candy baking goods, coffee creamers, spreads, ice creams, frozen desserts, soups and gravies.