In the food industry, proteins of plant origin, such as soy proteins, are used as an economical substitute for proteins of animal origin, such as whey and casein , but limitations arise due to the functionality and stability of these proteins in different applications (Pasupuleti and Demain 2010). Protein concentrates contain between 50 and 80% protein, while protein isolates contain more than 90% (Hui, 2007). Soy protein isolates are used in baked goods to add texture and emulsifying properties with minimal change in food color and flavor (Riaz 1999). Additionally, the combination of soy protein concentrate and dried whey protein is used in baked goods as an economical substitute for milk (Riaz 1999). Whey and casein, although commonly found in milk, can be isolated and used in many other applications, such as the brand ingredient Simplesse, a fat substitute (Hui 2007). Simplesse uses microparticulation, in which milk proteins are denatured and folded into smaller proteins that mimic the lubricating nature of lipids (Hui 2007). The isoelectric pH range of soy protein, at which solubility is minimal and precipitation can occur due to hydrophobic interactions, is between 4.2 and 4.6 (Pabby 2009). The isoelectric pH range of casein is 4.5 to 4.7 (Pabby 2009). Once the casein is precipitated, the remaining supernatant contains the whey proteins, which can be removed by a process called salting out (Mine and Shahidi 2006). Ammonium sulfate added to the supernatant will dissociate and the ions will interact with the water to change the structure of the water and increase surface tension, leading to a decrease in solubility and the precipitation of nonpolar molecules, such as whey proteins (Mine and Shahidi 2006.... .. middle of article ......rk: SpringerScience + Business Media. 229 p. Poklar N, Vesnaver G. 2000. Thermal denaturation of proteins studied by UV spectroscopy. Riaz MN. 1999. Healthy cooking with soy ingredients 44 (3): 136. Ryan M, McEvoy E, Duignan S, Crowley C, Fenelon M, O'Callaghan DM, FitzGerald RJ 2008. of soy protein isolate and hydrolyzate J Food Chem 108(2):503-10. Thermo Fisher Scientific Inc. 2011. Analysis of protein assay data Rockford, IL: Thermo Fisher Scientific Inc. Available at : http://www.piercenet.com/browse.cfm?fldID=876769DB 5056-8A76-4ED7-480BC9A5AD92 Accessed November 20, 2011. Thompson LD, Dinh T. 2009. Food proteins – protein isolation and thermal stability. FDSC 4303/5305 Food Chemistry Laboratory Manual. Lubbock, Texas: Texas Tech University, Department of Animal and Food Sciences.