Studies on micellar calcium phosphate-cross-linkage in casein micelles and these properties
2007
Umeda, T.(Fukuoka-ken. Agricultural Research Center, Chikushino (Japan))
In milk, casein micelles 20 to 600 nm in diameter exist as colloidal particles. Casein micelles are highly hydrated and contain 6.6% of inorganic materials, the main constituents of which are calcium phosphate. Calcium and inorganic phosphate are present in excess of their solubilities and - as a result of their interactions with casein - are not precipitated as calcium phosphate. Thus, the mammary secretory cells are considered to be protected from the injury caused by the precipitate of calcium phosphate. Calcium phosphate in casein micelles, which is associated with casein, is called colloidal calcium phosphate (CCP) or micellar calcium phosphate (MCP). It is now recognized that casein micelles acts as carriers of calcium phosphate instead of a sole nutritive function as source of amino acids, calcium and phosphorous. The MCP plays an important role in maintaining the structure of casein micelles because casein micelles are disaggregated into submicelles when MCP is removed. However, there is no agreed option for the structure of casein micelle, and also the mechanism of linkage between MCP and casein molecules has been unsolved until now. In particular, to clarify the latter is very useful for the development of the milk products such as cheese making use of the characteristics of casein micelles. The objective of this study was to obtain the fundamental information about the structural stability of MCP, considering from such a view point of the integrity of casein micelles through the cross-linkage.
اظهر المزيد [+] اقل [-]