ANTIGENIC PROPERTIES OF ALBUMIN, GLOBULIN, AND PROTEIN-CONCENTRATE FRACTIONS FROM RICE BRAN

Alkali-extracted rice bran protein was tested for antigenic properties by development of polyclonal antibodies in the rabbit. Animals were a lso inoculated with soy protein isolate and nonfat dry milk. Titers, d etermined by enzyme-linked immunosorbent assay, for the three groups w ere compared. Soy protein isolate evoked the highest class G immunoglo bulin (IgG) antibody titer (21,845,000), followed by rice bran protein (655,000), and nonfat dry milk (27,000). Rice bran proteins consisted of 29% albumins, 23% globulins, and 20% glutelins. Albumins and globu lins made up 69% of the extractable protein. Albumins, globulins, and two rice bran protein concentrates, produced by extraction in alkali, followed by isoelectric precipitation or spray-drying, were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and react ed against the antibran protein polyclonal antibodies in Western blot analysis. A small amount of highly antigenic protein (approximately 16 kDa) was found in the alkali-extracted rice bran protein concentrates , but it was absent in the albumin and globulin protein fractions.