Protein Thermal Stability

Proteins are an essential to food as they contribute greatly to the physical properties of food through their ability to build or stabilize fibrillar structures, foams, emulsions, and gels (Belitz and others 2004). Additionally, they are the precursors for aroma and color compounds that are formed during enzymatic or thermal reactions during production, process or storage. Damodaran (1996) states that food proteins can be defined for practical purposes, as those proteins that are easily digestible, are non-toxic, abundantly available, functionally usable in food products, and are nutritionally adequate. As the world population increases and the need to provide inexpensive, but functional food proteins continue to grow, the food industry must look toward non-traditional sources of protein. By understanding the functional, chemical and physical properties of food proteins, the industry can be successful in finding ways to provide protein to the world population.

Food proteins are primarily made up of twenty common amino acids. Of these, there are eight essential amino acids for adults and nine essential for children. Essential amino acids are those that the body cannot produce and therefore, must be consumed by the individual. Each of the amino acids varies in chemical composition, net charge, chemical reactivity, hydrogen bonding potential and solubility (Damodaran 1996). The physiochemical differences such as chemical reactivity, net charge, and solubility can also be found in the protein. The amino acids are amphoteric, meaning they can behave as either an acid or a base and because they contain both an amine and a carboxyl group, at around a neutral pH, the molecule is a zwitterion (Damodaran 1996). Additionally, the...

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