Influence of drying temperature on the solubility, the purity of isolates and the electrophoretic patterns of corn proteins

A sequential extraction of proteins from whole corn kernels dried between 54 and 130 °C was performed in order to elucidate the effect of the drying temperature on the solubility, the purity and the electrophoretic patterns of the different classes of corn proteins. It was observed that albumin, globulin and zein solubilities dropped significantly when the drying temperature increased, while fractions solubilised as glutelin-G2 and glutelin-G3 increased until 110 °C before dropping slightly at 130 °C. The analysis of the solubility of different protein groups indicated that mechanisms other than the creation of new disulfide bonds between proteins occurred during the high temperature drying of corn. Except for glutelin-G1 and zein isolates, which were highly pure, the purities of albumin, globulin, glutelin-G2 and glutelin-G3 isolates after dialysis were influenced by the drying temperature. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) showed the disappearance of some water and salt-soluble polypeptides at high drying temperatures. The electrophoretic patterns of zein and glutelin-G1 were not significantly modified, although the solubility of zein was affected by the drying temperature.