In the food industry, plant-derived proteins, such as soy proteins, are used as an economical substitute for animal-derived proteins, such as whey of milk and casein, but limitations occur due to the functionality and stability of these proteins in different applications (Pasupuleti and Demain 2010). Protein concentrates contain 50-80% protein, while protein isolates contain more than 90% protein (Hui 2007). Soy protein isolates are used in baked goods to add texture and emulsifying properties with minimal changes to the color and flavor of the food (Riaz 1999). Additionally, the combination of soy protein concentrates and dried whey protein is used in baked goods as an economical substitute for milk (Riaz 1999). Whey and casein, while typically present in milk, can be isolated and used in many other applications, such as the branded ingredient Simplesse, a fat substitute (Hui 2007). Simplesse uses microparticulation, during which milk proteins are denatured and folded into smaller proteins that mimic the lubricating nature of lipids (Hui 2007). The isoelectric pH range for soy proteins, during 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 for casein is 4.5 to 4.7 (Pabby 2009). After casein precipitates, the remaining supernatant contains whey proteins, which can be removed through a process called salting-out (Mine and Shahidi 2006). Ammonium sulfate added to the supernatant will dissociate and the ions will interact with water to alter the structure of the water and increase surface tension, leading to decreased solubility and precipitation of non-polar molecules, such as whey proteins of milk (Mine and Shahidi 2006.... .. half of the 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. Thermal stability of isolated ingredients and soy protein hydrolysates. J Food Chem 108(2):503-10.Thermo Fisher Scientific Inc. 2011. Protein assay data analysis Rockford, Illinois: Thermo Fisher Scientific Inc. Available from: http ://www. piercenet.com/browse.cfm?fldID=876769DB 5056-8A76-4ED7-480BC9A5AD92 Accessed 20 November 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.