The colloidal phosphate of milk: III. Nature of its association with casein

Abstract

Removal of colloidal phosphate leads to changes in the properties of milk of which the increased viscosity and greatly increased sensitivity to calcium salts, and the apparently diminished degree of mutual integration of the various casein fractions are the most striking. Re-introduction of colloidal phosphate restores incompletely and only in certain instances the original properties of the milk.These observations are interpreted as favouring the conception of chemical links between colloidal phosphate and casein in milk.* For brevity the term colloidal phosphate will be used in this paper.

Chemical Properties of Cryocasein

“…ness, 1984). This effect of colloidal calcium phosphate structure on the stability of casein to Ca*+ was also observed in milk systems (McGann and Pyne, 1960).…”

Influence of colloidal calcium phosphate level on the microstructure and rheological properties of rennet-induced skim milk gels

“…At this pH both casein micelles and chymosin have a negative charge (Zoon, van Vliet, & Walstra, 1989). McGann and Pyne (1960) concluded that removal of CCP from the micelles increased the viscosity of milk and caused a decrease in the rate of associations of casein components, which explains the retardation of rennet gel formation in our study (Fig. 2).…”

Casein structures in the context of unfolded proteins

“…In the 1960s the presence of so-called colloidal calcium phosphate in casein micelles was already well known (McGann & Pyne, 1960) but its intimate relationship with the phosphate centre sequences of the calcium-sensitive caseins was not recognised until later (Aoki, Yamada, Tomita, Kako, & Imamura, 1987;Gagnaire, Pierre, Molle, & Léonil, 1996;Holt, Davies, & Law, 1986;Holt, et al 1989;Ono, Ohotawa, & Takagi, 1994). The calcium phosphate-binding motif (Fig.…”