Protein Thermal Stability Essay -- Scientific Research, Soy Proteins

Proteins are amazing chemical polymers. They serve a myriad of functions such as providing nutrition in the form of their constitutive amino acids as well as energy. They serve as reactants and enzymes in chemical reactions. Proteins contribute to the texture, viscosity and water holding capacity of foods that contain them. Proteins can be toxins or allergens or hormones, and they serve as transporters for vital molecules such as oxygen in the blood stream (Coultate 1984). These polymers have evolved to play a role in very specific physiological functions and this chemical reactivity can be used for very unique applications beyond a proteins evolutionary scope. A protein’s chemical and physical nature such as the isoelectric point, solubility and size, and its biological attraction to other molecules all can be exploited to separate a particular protein from the solution in which is resides. Typically several steps are used to purify a particular protein. These include heating, acidification, subjecting a solution to reducing conditions, and drying. More sophisticated techniques include chromatography, ultra filtration, reverse osmosis, and high-pressure liquid chromatography (Kinsella and Whitehead 2001). The isolation of proteins from their original matrices allows for their use in different food systems to improve such qualities as nutritional value, texture, and stability. In order for a protein to serve in the latter capacities it must have certain characteristics such as solubility, gelation, ligand-binding or film formation properties. Today there is extensive use of non-native proteins to improve food quality. Products include ice creams, beverages, cereals, baked goods, snack items and dairy items ... ...1979. Functional properties of soy proteins. Journal America Oil Chemists’ Society 56:242-258. Kinsella JE and Whitehead. 1989. Proteins in whey: Chemical, physical and functional properties. Advances in food and nutrition research 33:343-439. McMahon DJ and Brown RJ. 1984. Composition, structure and integrity of casein micelles: A review. Journal of Dairy Science 67:499-512. Mendel F, and Brandon DL. 2001. Nutritional and health benefits of soy proteins. Journal of Agriculture and Food Chemistry 49(3):1069-1086. Southward CR. Casein Products. New Zealand Dairy Research Institute. Thompson LD., Dinh T. 2009. FDSC 4303/5305 food chemistry laboratory manual. Lubbock, TX: Texas Tech University, Department of Animal and Food Sciences. Walstra P. 1990. On the stability of casein micelles. Journal of Dairy Science 73:1965-1979.