casein

(redirected from Casein protein)
Also found in: Dictionary, Thesaurus, Medical.

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,
..... Click the link for more information.
 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 ?
The overall result indicated that the total protein synthesis response after consuming either a whey or casein protein supplement post-exercise was beneficial, and that neither supplement displayed a significantly superior response.
Researchers surmised that the availability of leucine and amino acids presented by the "fast" whey protein provided greater bioavailability in the elderly than the mixed meal of "slow" casein protein.
5 g-kg-1 of body weight (BW) per day of either whey or casein protein for 10 weeks.
Although the finding from the current study were statistically significant and improved the overall knowledge of protein supplementations and female athletes, more studies comparing the consumption of whey and casein protein pre- and post-exercise are needed to further determine if and/or how the two protein types differ in promoting hypertrophy and improving anaerobic performance.
The combination of a controlled undulating resistance training program with pre- and post-exercise protein supplementation had a significant impact on performance and body composition factors for both whey protein and casein protein groups.
Whey and casein protein can both have a positive effect on athletic performance; whey's fast absorption properties may be used to promote rapid protein synthesis, whereas casein is the ideal protein supplement to sustain the anabolic environment necessary for muscle growth over a longer period of time.
Science in Sport has supported research to demonstrate the positive effect that casein protein can have on performance.
The key findings of this study indicate that the consumption of a casein protein beverage before sleep had two main positive effects.
In a study on whey and casein proteins he identified that whey protein induced a dramatic but short increase of branched chain amino acids in the plasma, whereas casein was absorbed more slowly during a longer period of time.
Casein proteins are especially important for cheesemaking.
In a talk entitled "Immunoaffinity Extraction and 180 Labeling of Allergens in Dark Chocolate," Kevin Shefcheck of the FDA's Center for Food and Safety and Applied Nutrition discussed the use of magnetic beads to extract casein proteins, noting that immunoaffinity methods provide a simple, fast and multiplexed solution.
The investigators believe the casein proteins in milk act to modify the normally bioactive ingredients in the tea, undercutting its usual cardiovascular benefits.