FUNCTIONAL-PROPERTIES OF NATIVE AND MODIFIED WHEAT-GERM PROTEIN ISOLATES AND FRACTIONS

Osborne-type protein fractions and alkaline wheat germ protein isolate were produced and the latter was modified by urea-treatment, reductio n and re-oxidation. The effects of modification on the protein subunit structure and on functional properties were investigated. Emulsifying activity, emulsion stability, solubility and aromatic surface hydroph obicity of 'native' and modified products were determined. Usually, th e functional properties of the wheat germ protein isolate and the frac tions were lower compared to casein. The comparison of Osborne-fractio ns, showed that albumins and glutelins have better functional properti es than those of alkaline isolation and the globulin fraction. The res ults of the modification processes used in this work show, that only t he elimination of hydrogen bonds have significant effects on solubilit y, emulsifying stability and surface hydrophobicity. These results ind icate that hydrogen bonds play a main role in the formation of wheat g erm protein structure.