| Abstract: | Gels of glycinin and conglycinin formed at various heating temperatures, in the absence and presence of 0.2M sodium chloride were characterised by transmission electron microscopy. In distilled water both proteins formed gels consisting of strands with a thickness of 10–15 nm. The strands of glycinin were very regular and cross sections of strands showed a hollow cylindrical structure. In the presence of sodium chloride, glycinin formed an aggregated gel structure at 85°C, but at 95°C an ordered strand structure was formed. Dissociation of the quaternary structure on heating and reassociation of subunits into regular strands were considered the most probable mechanisms for strand formation from glycinin. The aggregated structure at 85°C was interpreted as a transient state prior to dissociation. Conglycinin rich gels were less regular and more crosslinked than gels of glycinin. Also, the strands of conglycinin showed a complex mode of aggregation possibly in the form of double spirals. The addition of sodium chloride caused a denser and more aggregated structure at 75 and 85°C, but the effects were not as drastic as in the case of glycinin. Heating temperature had only minor effects on the gel structure in the range studied. |
