Modification of functional properties by rearrangement of disulfide bonds and change of ratio of protein fractions

The growing use of different protein isolates (and concentrates) in food production in many cases requires modification of functional properties of isolates in order to assure the optimal physical (nutritional) properties of the endproduct. A number of possible ways of modification is known including chemical, physical procedures and also use of recombinant gene technology. Such technologies are in many cases expensive and are connected with food safety problems. In search for relatively cheap and safety process we studied the possibilities of applying rearrangement of disulfide bonds and change of ratio of protein fractions. The models used in experiments were: gluten-, soy-, pea-, and wheat germ proteins. It was found that gluten polypeptide mixtures of same composition reoxydized under different conditions were transformed to protein masses of quite different functional properties. The same procedure resulted in only slight changes in the case of reduction and reoxydation of legume- and wheat germ proteins. The study of some protein mixtures showed that the functional properties did not change linearly with the composition of the mixture. In many cases maxima of some parameters were observed.