Casein Protein

同義語： Casein, Caseinate, Milk Protein, Bos taurus casein, Calcium caseinate, Sodium caseinate, Micellar casein.

Casein is the predominant phosphoprotein found in mammalian milk, constituting approximately 80% of the total protein content. It exists as a heterogeneous mixture of four primary types—alpha-s1, alpha-s2, beta, and kappa-casein—which self-assemble into stable micellar structures in aqueous environments. These micelles are held together by calcium phosphate bridges and hydrophobic interactions, giving casein its characteristic slow digestion profile and excellent emulsifying capacity. In industrial and nutritional applications, casein is valued for its high essential amino acid content, particularly glutamine and proline, and its ability to form gels under acidic or enzymatic conditions.

Commercially, casein is produced from skim milk through acid precipitation or enzymatic coagulation, followed by washing, drying, and milling. Depending on the production method, it yields different functional grades: acid casein, rennet casein, and micellar casein. Each grade varies in mineral content, solubility, and viscosity, making them suitable for specific applications. For example, acid casein is commonly used in cheese analogs and bakery products, while micellar casein is preferred in sports nutrition and clinical enteral formulas due to its sustained amino acid release.

Beyond nutrition, casein serves as a versatile ingredient in adhesives, paper coatings, and biodegradable plastics, thanks to its film-forming and binding properties. Its ability to form complexes with other biopolymers also makes it useful in encapsulation and controlled-release systems. As a well-characterized and widely available protein, casein remains a staple in both research and industrial formulations.

化学構造と性質

Casein is a phosphoprotein with a molecular weight ranging from 19 to 25 kDa, depending on the fraction. It contains a high proportion of proline residues, which disrupt regular secondary structures, resulting in a largely random coil conformation. The protein is amphiphilic, with distinct hydrophilic and hydrophobic regions that drive micelle formation. Its isoelectric point is typically around pH 4.6, where solubility is minimal. Casein is rich in phosphate groups esterified to serine residues, which facilitate calcium binding and contribute to its colloidal stability.

作用機序

• Slow digestion: In the stomach, casein clots under acidic conditions, delaying gastric emptying and providing a sustained release of amino acids into the bloodstream.
• Calcium binding: Phosphoserine residues chelate calcium ions, forming soluble complexes that enhance calcium absorption in the intestine.
• Emulsification: The amphiphilic nature of casein allows it to stabilize oil-in-water emulsions by reducing interfacial tension.
• Gelation: Enzymatic or acid-induced gelation creates a three-dimensional network, useful in food texturing and encapsulation.
• Bioactive peptide release: Enzymatic hydrolysis of casein generates peptides with antihypertensive, immunomodulatory, and antimicrobial activities.

品質仕様

供給および書類

• 容量: 500 metric tons per month
• リードタイム: 3～5営業日（在庫品）
• ドキュメント: COA, MSDS, TDS, nutritional analysis, allergen statement
• パッケージ: 25 kg multi-wall bags with polyethylene liner; custom packaging available

見積依頼

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