Effects of NaCl and temperature on the gelation of soybean glycinin

Abstract

Gelation process is a complicated process in which the solvent conditions affect the network characteristics. The effects of ionic strength, pH, and heat treatment in the soy protein molecules have been studied on both molecular level and on rheological properties. This chapter describes the effects of NaCl and heat treatment on the gelation process by dynamic viscoelastic measurement, Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Effects of NaCl and heat treatment on the gelation of glycinin dispersions are studied by dynamic viscoelastic measurement, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Storage shear modulus G' and the absorbance at 1618 cm-1 in FTIR spectrum for glycinin dispersions as a function of the added NaCl concentration become maximum at 0.5% NaCl. The endothermic peak in DSC heating curves shifts to higher temperatures with increasing concentration of the added NaCl. The shift of the endothermic peak to higher temperatures with increasing concentration of the added NaCl is attributed to the stabilization of glycinin molecules by the addition of salt.