Protein Thermal Stability Essay -- Scientific Research, Food Industry

In the food industry, plant-derived protein, such(prenominal) as soy protein, is being employ as an economical replacement for animal-derived proteins, such as whey 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 greater than 90% protein (Hui 2007). Soy protein isolates are use in bakery goods to add texture and emulsification properties with minimal change to the color and flavor of the food (Riaz 1999). In addition, the combination of soy protein concentrates and dried whey protein is used in bakery products as an economical replacement for milk (Riaz 1999). Whey and casein, while typically found in milk, can be isolated and utilized in many other applications, such as the branded ingredient Simplesse, a fat replacer (Hui 2007). Simplesse employs microparticulation, during which milk proteins are decharacte rd and folded into smaller proteins that mimic the lubricating nature of lipids (Hui 2007). The isoelectric pH range for soy protein, during which solubility is minimal and precipitation may occur due to hydrophobic interactions, is between 4.2 to 4.6 (Pabby 2009). The isoelectric pH range for casein is 4.5 to 4.7 (Pabby 2009). afterwards casein precipitates, the remaining supernatant contains the whey proteins, which may be removed through a process called salting-out (Mine and Shahidi 2006). Ammonium sulfate added to the supernatant will divorce and the ions will interact with the water to alter waters structure and increase surface tension, leading to the decreased solubility of and precipitation of nonpolar molecules, such as whey proteins (Mine and Shahidi 2006... ...rk SpringerScience + Business Media. 229 p.Poklar N, Vesnaver G. 2000. Thermal denaturation of proteins studied by UV spectroscopy. JChem Edu 77(3)380-2. Riaz MN. 1999. Healthy baking with soy ingredients. Cerea l nutrient World. 44 (3)136.Ryan M, McEvoy E, Duignan S, Crowley C, Fenelon M, OCallaghan DM, FitzGerald RJ. 2008.Thermal stability of soy protein isolate and hydrolysate ingredients. J Food Chem108(2)503-10.Thermo Fisher Scientific Inc. 2011. Protein assay data analysis. Rockford, Ill. Thermo FisherScientific Inc. visible(prenominal) from http//www.piercenet.com/browse.cfm?fldID=876769DB5056-8A76-4ED7-480BC9A5AD92. Accessed Nov 20, 2011. Thompson LD, Dinh T. 2009. Food proteins protein isolation and thermal stability. FDSC4303/5305 food chemistry laboratory manual. Lubbock, Tx. Texas Tech University,Department of Animal and Food Sciences.