LAUSR

Abstract The main purpose of this work was to investigate the effect of electrostatic combination between ovalbumin (OVA) and carboxymethylcellulose (CMC) with different substitution degree (CMC0.7 and CMC1.2, the higher substitution degree means greater charge density) on the thermally induced gelation behavior of OVA. It has been found that electrostatic combination with CMC greatly inhibited OVA thermal gelation, and CMC 1.2 with higher charge density exhibited stronger inhibition than CMC 0.7. Rheological fractal analysis showed that the thermogels of OVA/CMC 0.7 and OVA/CMC 1.2 electrostatic complexes were in the transition ragime. Furthermore, as the OVA-CMC ratio increased from 10:1 to 40:1, the fractal dimensions of the OVA/CMC 0.7 and OVA/CMC 1.2 thermally induced gels increased from 1.83 and 1.75 to 2.17 and 2.08, respectively. This result indicated that an increasing in the proportion of protein resulted in a more compact fractal aggregate structure, allowing the gel to exhibit a higher elasticity modulus (G′). On the other hand, the charge shielding effect of salt ions enhanced the thermogel strength of the OVA/CMC complexes. However, when salt ions (100 mM) completely dissociate the protein molecules on the polysaccharide chain, the apparent viscosity of the polysaccharide has a strong influence on the thermal gelation of OVA. At this time, CMC 0.7 having a lower charge density exhibited a stronger anti-gelation ability of OVA than CMC 1.2 because of its higher apparent viscosity. This kind of novel OVA/CMC electrostatic complexes thermogel could provide a potential new approach to the design and regulation of food texture.