An Improved Isolation Method of Soy β‐Conglycinin Subunits and Their Characterization

Abstract This study aimed at establishing an effective preparative isolation method of soy β‐conglycinin constituent subunits and characterizing some of their physicochemical properties and their heat‐induced aggregation. These subunits were isolated in relatively large amounts and in high purity by dissociating β‐conglycinin in 6 M urea and using a combination of DEAE‐Sepharose fast flow column chromatography and immobilized metal ion affinity chromatography (IMAC). At a pH deviating from isoelectric point (p I ), zeta potentials of α′ and α subunits were much larger than that of β subunit, while in the latter case, the hydrophobic groups were more buried within the proteins. Dynamic light scattering analysis indicated that the extent of heat‐induced aggregation of β subunit was much higher than that of α′ and α subunits, and the aggregation was also more affected by the increase in ionic strength. Atomic force microscopy analysis indicated that more ordered and stranded aggregates were formed for α′ and α subunits. These results confirm a close relationship between physicochemical properties and heat‐induced aggregation of β‐conglycinin subunits.