Casein properties

In general, high protein content and solubility are desirable casein properties. Fat, lactose, moisture, ash, bacteria, and odor are expected to be low. Light-colored material is also preferred. The viscosity and particle size sought depend on the compounding practices and intended use of the adhesive. 

Definition Ammonium salt of casein Properties Anionic... 

Definition Calcium salt of casein Properties Wh. or si. yel. powd., nearly odorless insol. in cold water... 

Synonyms Casein, potassium salt Caseins, potassium complexes Definition Potassium salt of casein Properties Off-wh. solid Toxicology TSCA listed Uses Antistat in cosmetics flavoring agent in dairy prods., margarine, frozen custard, fruit sherbets binder emulsifier for low sodium dietetic foods... 

Definition Sodium salt of casein Properties Wh. coarse powd., odorless, tasteless insol. in water, alcohol... 

Synonyms Casein, potassium salt Caseins, potassium complexes Definition Potassium salt of casein Properties Off-wh. solid Toxicology TSCA listed... 

Protein-Based Substitutes. Several plant and animal-based proteins have been used in processed meat products to increase yields, reduce reformulation costs, enhance specific functional properties, and decrease fat content. Examples of these protein additives are wheat flour, wheat gluten, soy flour, soy protein concentrate, soy protein isolate, textured soy protein, cottonseed flour, oat flour, com germ meal, nonfat dry milk, caseinates, whey proteins, surimi, blood plasma, and egg proteins. Most of these protein ingredients can be included in cooked sausages with a maximum level allowed up to 3.5% of the formulation, except soy protein isolate and caseinates are restricted to 2% (44). 

In the late 1800s, when the demand for coated paper for the halftone printing process increased, casein rapidly replaced glue. Casein forms a hard, tough film when dry, and can be waterproofed easily with formaldehyde (qv). The properties of soy protein are similar to those of casein, and soy protein has been substituted for it in many types of coated papers requiring a casein-type binder (see Soybeans and other oilseeds). Casein, a valuable food product, is seldom used as a paper adhesive, in spite of its excellent adhesive properties. 

Reclaimed mbber, which is widely used in dry mbber, has Htde use in latex compounding. A dispersion or artificial latex of the red aim must be made by a rather expensive process of milling in dispersing agents, eg, soaps and casein, and water. Some reclaim dispersions are used in latex compounds for such things as spread mbber goods and adhesives and fiber binders to reduce cost. However, for most latex compounds, it is not desirable because of the poor physical properties it imparts and the resultant darkening of the compound. 

A useful property of the red seaweed extracts is their abiUty to form gels with water and milk. Kappa-carrageenan reacts with milk protein micelles, particularly kappa-casein micelles. The thickening effect of kappa-carrageenan in milk is 5—10 times greater than it is in water at a concentration of 0.025% in milk, a weak thixotropic gel is formed. 

A significant problem is the wide variation in properties in the same type of product both from different manufacturers and from the same source. More recendy there has been vast improvement in the consistency of these products from a given manufacturer and usage in dairy substitutes is expected to expand. These isolates do have a higher protein efficiency ratio (PER) than casein and are equal to egg protein. 

Soybean Protein Isolates. Soybean protein isolates, having a protein content of >90 wt%, are the only vegetable proteins that are widely used in imitation dairy products (1). Most isolates are derived from isoelectric precipitation, so that the soybean protein isolates have properties that are similar to those of casein. They are insoluble at thek isoelectric point, have a relatively high proportion of hydrophobic amino acid residues, and are calcium-sensitive. They differ from casein in that they are heat-denaturable and thus heat-labile. The proteins have relatively good nutritional properties and have been increasingly used as a principal source of protein. A main deterrent to use has been the beany flavor associated with the product. Use is expected to increase in part because of lower cost as compared to caseinates. There has been much research to develop improved soybean protein isolates. 

Table 30.1 Properties of rennet casein. Determined according BS1416 1961...

Dried casein in normally imported into Great Britain largely from New Zealand and to some extent France and Scandinavia. Some typical properties of the proteins as imported are shown in Table 30.1. 

Formolised casein is a rigid hom-like material which may be made available in a wide variety of colours and patterns. By common consent it is recognised as having a pleasant feel and appearance and it is properties which are relevant to cuiTent commercial application. 

Table 30.2 Some physical properties o casein plastics...

Both acids and alkalis will adversely affect the material. Strong alkalis and acids will cause decomposition. The water absorption is high and consequently casein is easily stained. As a corollary to this it may be dyed without difficulty. Acidic and basic water-soluble dyes are normally used. Typical properties of casein plastics are given in Table 30.2. 

Chemical nature Isolation of casein from milk Production of casein plastics Properties of casein Applications Miscellaneous Protein Plastics Derivatives of Natural Rubber Gutta Percha and Related Materials Shellac... 

The utilization of the vegetable gums, especially those with good filmforming properties, to suspend the solids in paints of the casein and emulsion types, still offers a wide field for experimentation and application. 

Miguel, M., Contreras, M. M., Redo, 1., and Aleixandre, A. (2009). ACE-inhibitory and antihjqjertensive properties of a bovine casein hydrolysate. Food Ghent. 112, 211-214. 

Caseins are the major proteins in bovine milk and about 95% of the caseins exist as casein micelles. The structure and properties of casein micelles influence a wide range of technological uses of milk. Light microscopy, SEM, and TEM have been frequently used to study casein... 

Helstad, K. M., Bream, A. D., Trckova, J., Paulsson, M., and Dejmek, P. (2005). Nano-heological properties of casein. In "Food Colloids Interactions, Microstructure and Processing", (E. Dickinson, Ed.), pp. 218-229. The Royal Society of Chemistry, Cambridge. 

The precipitation of casein in its uncombincd form by the addition to milk of one or another acid, forms the basis of all methods of preparation. These differ widely, however, in the subsequent purification. In the method of Hammarsten,4 just enough alkali is added to dissolve this casein completely. The alkalinity reached in this process somewhat modifies its physical properties but probably not its composition. In the method of Van Slyke and Bosworth 5 the last trace of calcium is removed by adding oxalate to an ammoniacal solution of the casein, but... 

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