Huppertz, T,Hennebel, JB,Considine, T,Shakeek-Ur-Rehman,Kelly, AL,Fox, PF;

2006

June

Food Chemistry

A method for the large-scale isolation of beta-casein

Validated

()

beta-casein isolation milk TEMPERATURE-DEPENDENT DISSOCIATION CHEESE-MAKING PARAMETERS MILK-CLOTTING ENZYMES BOVINE-MILK GEL CHROMATOGRAPHY SOLUBLE PHASES SERUM CASEIN PLASMIN FRACTIONATION MICELLES

99

45

50

A method for the large-scale isolation of beta-casein from renneted skim milk was developed. The Curd from renneted skim milk was dispersed in hot (>= 70 degrees C) water to inactivate residual chymosin. The heated curd was subsequently recovered by centrifugation. resuspended in water and incubated at 5 degrees C, during which P-casein dissociated from the curd, the suspension was centrifuged and the aqueous phase lyophilised. The isolated protein consisted mainly of beta-cascin, containing a minor amount of gamma-caseins and traces of other caseins. Unless chymosin was fully inactivated by heating, some beta-casein was hydrolysed at the Leu(192)-Tyr(193) bond. The yield of beta-casein increased with incubation time, up to similar to 20% of the beta-cascin present in the milk after 24 h at 5 degrees C. Reducing milk pH to 5.5 or 6.0, prior to renneting, caused a high level of contamination with alpha(s)-cascins. This isolation procedure can be easily scaled-up to an industrial process and the beta-casein-depleted curd may be used for the manufacture of rennet casein or processed cheese. (c) 2005 Elsevier Ltd. All rights reserved.

DOI 10.1016/j.foodchem.2005.07.025