ABSTRACT

Du r in g postharvest storage and processing, the proteins in food systems are exposed to conditions favoring different chemical interactions of their functional groups with oxygen and with various reactive components in the environment. The rate of these reactions is affected predominantly by the state of the structure of the respective food, temperature, pH, water activity, ions, and radicals-mainly the active forms of oxygen, as well as other food com­ ponents, especially lipids and saccharides. The products of these interactions may have positive or detrimental effects on food quality, some of them have a diagnostic value, informing on the extent of changes that take place in foods during storage and processing. Chemical reactions are also used intentionally in technological processes and for modification of functional properties of pro­ teins in research on the structure-function relationship, although for practical application, more emphasis is actually being placed on enzymatic methods of modification.