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Product Description: Biochemical research; Biological medium.
Solubility: Insoluble in water, soluble in alkaline aqueous solution, soluble in concentrated hydrochloric acid is light purple
Storage condition: Dry at room temperature
Uses: Biochemical research; Biological medium.
Product properties: Casein is an amphoteric protein with an isoelectric point pH4.8. In milk in the form of dicalcium phosphate, tricalcium phosphate or a complex of the two, the structure is extremely complex, until now there is no fully determined molecular formula, molecular weight of about 57000-375000. Casein contains about 3% of milk and accounts for about 80% of milk protein. Pure casein is a white, odorless, odorless granular solid. The relative density is about 1.26. Insoluble in water and organic solvents. Casein absorbs water, and when immersed in water, it expands rapidly, but the material does not bond.
Preparation method: (1) Degreasing fresh milk, adding acid (lactic acid, acetic acid, hydrochloric acid or sulfuric acid), adjusting pH to 4.8, so that casein micelles lose charge and coagulate and precipitate. Casein obtained by this method is called acid casein, and the acid casein obtained by different kinds of acid is almost indistinguishable. Acid casein is a white to pale yellow powder or particle with a slight milk odor and sour taste. In water only swelling, if adding ammonia, alkali and its salt, it can be dispersed in water. Soluble in strong acid, diethanolamine, morpholine, urea, formamide, hot phenol and Turkish red oil. (2) The action of milk with crude rennet to form a coagulated precipitate, called crude rennet casein, white granular, almost tasteless and odorless, heating and burning will produce a unique odor. Rennet casein has a higher ash content than acid casein.
Application: Acid casein is mainly used as the base material of paint, binder of wood, paper and cloth, food additive and so on. As the base material of the paint accounts for about half of the total consumption, it has excellent water resistance, can be well dispersed in the pigment, and improve the uniformity of the paint. In addition, due to good fluidity and easy coating construction, crude rennet protein is mainly used in the manufacture of plastic buttons. Compared with other resin buttons, casein buttons have good dyeing, processability and bright color, and the quality is in the middle of the best buttons. Casein is evenly mixed with slaked lime, sodium fluoride and copper sulfate, and then mixed with kerosene to obtain casein gum, which is a cement used in the aviation industry and wood processing sector. Casein is also used in medicine and biochemical reagents.
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