CHANGES IN SOLUBILITY AND DISTRIBUTION OF SEMOLINA PROTEINS DUE TO EXTRUSION PROCESSING

The effects of extrusion processing on wheat protein solubility and mo lecular weight distribution were investigated. Enriched semolina was e xtruded using a twin-screw extruder at two different temperatures (50 and 96 degrees C). A modified Osborne fractionation showed a marked de crease in albumin, globulin, gliadin, and glutenin fractions with a co ncomitant increase in the insoluble residue fraction following extrusi on. The effect on protein solubility was greater with the higher extru sion temperature. Sodium dodecyl sulfate polyacrylamide gel electropho resis patterns of reduced and unreduced protein fractions suggest that conformational changes occurring during extrusion may be responsible for the increase in the insoluble residue fraction.