Functional Protein–Polysaccharide Conjugate Prepared by Controlled Dry-heating of Ovalbumin–Dextran Mixtures

A functional ovalbumin-dextran conjugate was prepared by dry-heated storage at 60 degrees C and 65% relative humidity for 3 weeks. The emulsifying properties of the ovalbumin-dextran conjugate were about three times higher than those of an ovalbumin-glucose conjugate. SDS-electrophoresis patterns showed that the ovalbumin-dextran conjugate obtained by dry-heating was not as polydispersed as that obtained by cyanogen bromide-activated dextran. The average molecular weight of the ovalbumin-dextran conjugate was about 200,000. The excellent emulsifying properties of ovalbumin-dextran conjugate were maintained even at pH 3 and were further improved at pH 10. In addition, the emulsifying properties of the ovalbumin-dextran conjugate were greatly enhanced by preheating the conjugate at 100 degrees C. Thus, it is suggested that an ovalbumin-dextran conjugate prepared by controlled dry-heating can be used as a macromolecular emulsifier for food applications.