Simulated milk ultrafiltrate

Jenness, R. and Koops, J. 1962. Preparation and properties of a salt solution which simulates milk ultrafiltrate. Neth. Milk Dairy J. 16, 153-164. 

Ruegg, M., Moor, U. and Blanc, B. 1977. A calorimetric study of the thermal denatura-tion of whey proteins in simulated milk ultrafiltrate. J. Dairy Res. 44, 509-520. 

Fig. 14. Angular dependence of the intensity of neutrons scattered by casein micelles suspended in simulated milk ultrafiltrate made with two different H20/2H20 mixtures. The arrow marks the point of inflection ascribed to the intersubunit interference. From Stothart and Cebula (1982), reproduced with permission.

Since milk is the vehicle by which the infant mammal obtains its calcium and phosphorus requirements for growth, the fluid must contain large quantities of both elements. Both solid and solution phases coexist, but the solid phase is maintained in a colloidal state by interaction with protein and the nature of the solid state is of considerable interest.347 In the 3fP solution-state spectrum of whole cow s milk the inorganic phosphate time is broad on adding EDTA this narrows and increases in intensity. This is consistent with the dissolution of the solid phase and reduction of the interaction of the phosphate with either the solid phase and/or the protein.346 The temperature dependence of31P signal intensity has been measured in simulated milk ultrafiltrate solution (SMUF), a colloidal calcium phosphate-free milk (CCP-free) and a casein micelle suspension (CMS).345... 

A second mechanism, the possible interaction of aldehydes with amino acids or peptides forming Schiff base reaction products, was also studied. Initial results (Hansen, A. P. Heinis J. J., North Carolina State University, Raleigh, unpublished data) showed a decrease in the aldehyde concentration when model systems containing various aldehydes and amino acids were heat processed. Losses ranging from 8 to 50% of various aldehydes have been observed in the pasteurization of aldehydes and amino acids mixtures in simulated milk ultrafiltrate. 

Gao et al. [66] investigated the accuracy of calcium measurements in simulated milk ultrafiltrate and skim milk samples. They realized that the free calcium ion concentration is smaller in the sample than the total one owing to the ionic complex formation by phosphate, chloride, and citrate ions. Therefore, they recommend new standard solutions for calibration with ionic profile nearly the same as samples. Using those calibrating solutions, the systematic error could be substantially reduced. 

Whey protein concentrates (WPC), which are relatively new forms of milk protein products available for emulsification uses, have also been studied (4,28,29). WPC products prepared by gel filtration, ultrafiltration, metaphosphate precipitation and carboxymethyl cellulose precipitation all exhibited inferior emulsification properties compared to caseinate, both in model systems and in a simulated whipped topping formulation (2. However, additional work is proceeding on this topic and it is expected that WPC will be found to be capable of providing reasonable functionality in the emulsification area, especially if proper processing conditions are followed to minimize protein denaturation during their production. Such adverse effects on the functionality of WPC are undoubtedly due to their Irreversible interaction during heating processes which impair their ability to dissociate and unfold at the emulsion interface in order to function as an emulsifier (22). 

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