Gelation Phenomena Induced by Alkali-alcohol Treatment of 7S and 11S Components in Soybean Globulins

Transparent gels containing about 2 % protein were obtained by mixing alkaline dope solution of 7S or 11S soybean proteins with alcohol.The 7S component showed the ability to forma stronger gel than the 11S.This phenomenon depended on pH and alcohol concentration.In 66% ethanol, the viscosity of the 7S and 11S reached maxima at pH 11.4 and 11.2, respectively.Above these pH levels where further unfolding and dissociation into subunits of the protein molecules occur, the viscosity decreased rather.The effectiveness of alcohol to increase viscosity increased in the order; n-butanol < tert-butanol < n-propanol < iso-propanol 11) of acid precipitated soybean proteins gelled by dialysis against phosphate buffer (pH 7.2, a=0.5).Considering the parallel relationship between changes in viscosity and solubility of n-heptane into the dope solution, the exposure of hydrophobic regions seemed to contribute largely for keeping a gel network structure as well as disulfide and hydrogen bonds.On an alkaline