Abstract
The effect of ionic strength during heat denaturation was investigated on the surface hydrophobicity and surface functional properties of soybean 11S globulins. The change in surface hydrophobicity of the protein was examined during heating at different ionic strengths, and the value increased with heating temperature over the range of ionic strengths used. When the protein solution was heated at a low ionic strength, the surface hydrophobicity changed more with heating temperature and the thermal transition point was lower than that of the protein heated at a high ionic strength. This suggests that 1 IS globulins are more sensitive to heat at low ionic strengths than at high ionic strengths. The changes in surface functional properties of 11S globulins by heating were also investigated. The emulsion stability increased greatly with heating temperature in proportion to the increase in surface hydrophobicity. The emulsion of the protein heated at a low ionic strength was more stable than that of the protein heated at a high ionic strength, depending on the higher surface hydrophobicity. The emulsion stability of heated 11S globulins correlated linearly with the surface hydrophobicity at different ionic strengths. On the other hand, the foaming power produced a curvilinear correlation with the surface hydrophobicity.
