Protein Thermal Stability

Proteins are a series of connected amino acids, and in food products, proteins provide both nutritional and functional properties that contribute to the quality of a food system (Christen and Smith 2000). Protein in the diet is essential to the maintenance of life and health. Proteins are compounds with a function that do work in the body such as facilitate reactions; however, proteins are also functional in food systems. Proteins are used for a variety of reasons such as: to create an emulsion, join pieces of meat together, form a skin on the surface of a product, and form a stable foam matrix.

Milk proteins such as whey and casein are isolated for many different functions in food systems such as: foaming, whipping, gelation, nutrition, flavor enhancement, and emulsification (Punidadas and Rizvi 1998). Casein in milk compromises approximately 78% of proteins found in milk, and determining the amount of casein in milk is essential to cheese manufacturing (Punidadas and Rizvi 1998). Whey proteins in milk are often isolated from cheese production and are used for a variety of reasons such as a nutritional protein supplement. Whey protein isolates are also used as a whipping agent (Punidadas and Rizvi 1998). Milk proteins can be extracted in numerous ways such as the Wijis method, chromatography, and cross flow filtration (Punidadas and Rizvi 1998; Christen and Smith 2000).

Soy proteins are commonly used in commercial food products as a relatively inexpensive form of protein for many reasons. Soy can be added to meat products to increase the regulated amount of water that can be added to product. Soy proteins are also a good source of nutrition (L’hocine and others 2006). Soy proteins have functional properties si...

... middle of paper ...

...5: 256-259.

Punidadas P and Rizvi SSH. 1998. Separation of milk proteins into fractions rich in casein or whey proteins by cross flow filtration. Food Research International. 31(4): 265-272.

Ryan M, McEvoy, E, Duignam S, Crowley C, Fenelon M, O’Callaghan, DM, and FitzGerald RJ. 2008. Thermal stability of soy protein isolate and hydrosolate ingredients. Food Chem. 108: 503-510.

Stellwagen E and Wilgus H. 1978. Relationship of protein thermostability to accessible surface area. Nature. 275: 342-343.

Thompson LD and Dinh T. 2009. Acid-Base Chemistry. FDSC 5305 food chemistry laboratory manual. Lubbock, TX: Texas Tech University, Department of Animal and Food Sciences.

Vogt G and Argos P. 1997. Protein thermal stability: hydrogen bonds of internal packing? Distance-Based Approaches to Protein Structure Determination III Supplement 2: 40-46.