EFFECT OF HEAT DENATURATION ON THE STRUCTURE AND RHEOLOGICAL PROPERTIES OF OVALBUMIN AQUEOUS COLLOIDS

The effect of heat denaturation on the structure and properties of ovalbumin (OA) aqueous colloids in phosphate buffer solution has been studied using light scattering, small-angle X-ray scattering and rheological methods. The OA molecules associate with heat denaturation and the association process can be analysed by comparison with a first-order reaction. The denatured OA colloid is polydisperse and is composed of both polymeric and monomeric molecules. The radius of the cross section of the polymeric molecule is ca. 25 angstrom. The denatured OA colloid shows apparent yield stress and rigidity which are due to certain ordered arrangements of the molecules. The stress and rigidity remain almost constant over a wide range of OA concentration and increase sharply with gelation due to heat denaturation.