Role ofβ-Casein in Milk Curdling

Effect of β-casein concentration in cheese milk on rennet coagulation properties, cheese composition and cheese ripening

“…As a result, the rate of decrease of hardness was also slower for enriched cheeses and hardness stayed higher in enriched cheeses during cheese ripening. As suggested by Yun et al (1982), b-CN seems, effectively, to play a role in the hardening of cheese.…”

“…They have observed that rennet clotting was related to the proportions of a-CN and b-CN present in milk. Yun, Ohmiya, and Shimizu (1982) be essential for the hardening of curd. Therefore, any changes in the amount of a-CN or b-CN would alter properties of milk and cheese.…”

Enzymic dephosphorylation of bovine casein to improve acid clotting properties and digestibility for infant formula

“…Dephosphorylation of whole bovine casein or its components can be achieved to various degrees using a number of phosphatases (Yamauchi et al 1967;Bingham, 1976;Bingham et al 1976;Lorient & Linden, 1976;Reimerdes & Roggenbuck, 1980;Yun et al 1982a;Ohmiya et al 1983;Carles & Ribadeau-Dumas, 1986). Many workers have investigated the effects of dephosphorylation of casein on micelle formation (Pepper & Thompson, 1963;Whikehart & Rafter, 1970;Bingham et al 1972), calcium binding and sensitivity (Yamauchi et al 1967;Bingham et al 1972;Yoshikawa et al 1974;Aoki et al 1985), curd formation by rennet (Reimerdes & Roggenbuck, 1980;Yun et al 1982a, 6;Ohmiya et al 1983;Pearse et al 1986) and antigenicity (Otani et al 1987).…”

Structure and function of the phosphorylated residues of casein

“…Conversely, milk fortified with /?-casein, thus introducing additional phosphoseryl residues, formed a firmer curd than normal milk (Yun et al 1982 a). Fortification with chymosin-modified /?-casein, devoid of the hydrophobic moiety near the C-terminus, increased curd tension to the same extent as native /?-casein but trypsin treated /?-casein, which had lost some part of the hydrophilic or N-terminal region, gave curd tensions similar to native milk (Ohmiya et al 1981;Yun et al 1982a). If /?-casein, dephosphorylated by an acid phosphatase, was used to fortify the milk, a more fragile curd was obtained (Hasegawa et al 1981).…”

“…This effect is specific to /?-casein, since fortification of milk with either a Sl -casein (Ohmiya et al 1981) or dephosphorylated a Sl -casein (Yun et al 19826) had negligible effect on curd firmness. Consolidation of the coagulum was therefore concluded to involve interactions between Ca 2+ ions and phosphate groups bound primarily to /?-casein molecules (Yun et al 1982a). Blockage of these phosphate groups has also been advanced as one explanation for the soft curd that is obtained when milk is homogenized before proteolysis (Ohmiya et al 1983).…”