Micellar calcium phosphate-cross-linkage in porcine casein micelles
2005
Umeda, T.(Fukuoka-ken. Agricultural Research Center, Chikushino (Japan))
The composition of porcine casein micelles and physico-chemical properties of micellar calcium phosphate (MCF)-cross-linked casein in porcine casein micelles were investigated. The micellar casein content was 3.47-4.07% in porcine skim milk; this value was 1.48-1.73 times higher than that of bovine skim milk. The total calcium, micellar calcium and inorganic phosphorus contents were also higher in porcine milk than in bovine milk. The micellar inorganic phosphorus content was 1.52-3.29 times higher in porcine milk than in bovine milk. The (MCP)-cross-link ed casein was separated from porcine casein micelles by high-performance gel chromatography on a TSK-GEL G4000SWxl column using 6 M urea-simulated milk ultrafiltrate as the eluent. The MCP-cross-linked casein in porcine casein micelles was 66.6-69.2% of total casein. These values are higher than those in corresponding casein micelles of Holstein cow milk, which were 57%. The total casein content of porcine milk was higher than that of bovine milk. The little increase in serum casein was observed when porcine skim milk was cooled for 2 to 24 h at 5 deg C. This suggested that porcine casein was more easily cross-linked by MCP than bovine casein, and that a high content of MCP-cross-linked casein might depress the dissociation of porcine casein micelles on cooling.
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