Food Chemical Studies on Soybean Proteins

Part XI. Stabilization of soybean proteins with sucrose, glycerol and ethylene glycol

Abstract

Stabilization of soybean proteins with sucrose, glycerol and ethylene glycol was studied. At low ionic strength (μ=0.1), their stabilizing effect on inhibiting the aggregation of water extracted protein at various pH was slight, but, at high ionic strength (μ=0.5), it was recognized clearly in order of sucrose glycerol ethylene glycol as 20% (v/v) of addition, respectively. Addition of 20% sucrose was effective on inhibiting the aggregation of the protein near its isoelectric point by heating (80°C for 30min).
Also, addition of 20% sucrose inhibited the dissociation of the 11S component to 7S at alkaline pH, but didn't inhibit the dissociation to 3S at acidic pH and had stabilizing effect to prevent the polymerization of the 3S. By measuring differential ultraviolet spectrum of the 11S component, it was shown that the sucrose inhibited the conformational change of the tertiary structure at acidic pH.