Structure‐Digestibility Relationship of Legume 7S Proteins

Structure‐digestibility relationship was investigated in in vitro model systems for phaseolin and vicilin, the major 7S storage proteins of dry bean and green peas, respectively. Native phaseolin was more resistant to trypsinolysis than vicilin, while heating caused a reversal of proteolysis rates. Conformational studies using far‐uv and near‐uv CD spcctroscopy suggested the native conformatin of vicilin to be far more flexible to thermal treatment and SDS‐induced environmental changes; however, neither the thermal treatment nor the anionic detergent caused a complete randomization of structure in either proteins studied. Ironically, the flexible native conformation of vicilin seemed to induce greater undesirable changes upon heating so as to confer resistance to proteolysis. The possible role of secondary and quarternary structures of these two proteins is descussed in relation to their digestibility.