HYDRODYNAMIC CHARACTERIZATION OF LUPIN PROTEINS - SOLUBILITY, INTRINSIC-VISCOSITY, AND MOLAR-MASS

The solubility, intrinsic viscosity ([eta]), and sedimentation behavio r of a lupin protein system extracted from Lupinus luteus seeds have b een determined. The results were compared with those published in the literature for soy proteins. The relationship between solubility and p H for the lupin protein isolate was similar to that reported in litera ture for soy isolates. The [eta] of the lupin protein isolate was simi lar to 7 mL/g. These values are comparable to those obtained by other authors for soy proteins. Sedimentation velocity studies suggested tha t there are three main globulins in lupin protein with sedimentation c oefficients of 13, 7, and 2S. The molar mass of the major lupin globul in (390 000 g/mol) was slightly higher than reported for the soy 11S g lobulin (340 000 g/mol), but the lupin 7S component gave a much smalle r value (105 000 g/mol) than the soy 7S (180 000 g/mol). The consequen ces in thickening and thermal gelation properties of the lupin protein system are discussed.