Preparation of a Caseinate Model System

A fundamental basis is contributed for studying physical and chemical changes resulting from processing and storing of concentrated milk. A simple model caseinate system was prepared by supercentrifuging the calcium caseinate-calcium phosphate complex from skimmilk, either fluid or reconstituted from low-heat nonfat dry milk, and then dispersing the complex in air-free whey, water, or artificial sera at 4 or 60 C. A "residual fraction" of five to ten per cent of the original casein remained in the supernatant. Redispersing caseinate in water formed a new residual fraction, but in artificial sera containing citrate, sodium, and calcium, more of the residual fraction developed, indicating dissociation of the complex and sodium caseinate formation. Model systems of the concentrated caseinate increased in viscosity during storage, and gelled. Editor.