Does heat exposure affect the properties of an MPC/MPI?

Yes. The degree of heat exposure will determine the solubility of the whey proteins in MPC/MPI and the stability of casein micelles over time. High heat exposure denatures almost all of the whey proteins in MP/MPI and initiates casein micelle aggregation, eventually resulting in a loss of solubility. A low heat MPC/MPI will contain higher amounts of undenatured, biologically active whey proteins and should have a longer shelf storage life. In general, one can say that a low heat powder will be more water soluble (the proteins are not heat denatured and aggregated) and have better sensory properties (whiter in color and lower levels of off flavors). High heat powder, in contrast, will be the least soluble.

High heat powders are used in the baking industry, where use of casein is desired for providing extra volume to baked goods, while whey proteins, if undenatured when included in the recipe, will decrease baked goods volume as they heat denature during baking. Medium heat powder, the most common type of powder because it is the easiest to manufacture, can be used in reconstituted milk beverages and as protein fortification of most food products. Wherever medium heat powder is used, low heat powder will do a better job. In high protein, UHT processed Ready to Drink beverages, for example, shelf life can be extended when starting with low heat MPC/MPI because of a complex formed between undenatured beta-lactoglobulin and kappa-casein during UHT treatment that has been shown to make the casein micelles more resistant to storage gelation.

Low heat powder also has a huge advantage over medium and high heat powders in nutritional applications. Whey proteins are renowned for their health providing benefits. Not many people, however, are aware that all of these health benefits apply only to native, undenatured whey proteins. High heat powders, therefore, would possess little or no whey protein health benefits.
By the same logic, medium heat powders possess less whey protein health benefits than low heat powders. The fact that IdaPro MPC-80 and MPI-85 have a significantly higher quantity of undenatured whey protein than any other MPC/MPIs tested make our products ideal for use in Nutritional applications.