Investigation into the physicochemical stability and rheological properties of beta-carotene emulsion stabilized by soybean soluble polysaccharides and chitosan.

In this study, the possibility of producing stable O/W emulsions incorporating beta-carotene in oil droplets surrounded by multiple-layer interfacial membranes has been demonstrated. Emulsions were prepared using a two-stage process by homogenization, which relied on the adsorption of chitosan to anionic droplets coated with soybean soluble polysaccharides (SSPS). Results showed that the zeta-potential, particle size, and rheological properties of emulsions were greatly dependent on the chitosan concentration. The electrical charge on the droplets increased from -34 to 58.2 mV as the chitosan concentration was increased from 0 to 2 wt %, which indicated that chitosan adsorbed to the droplet surfaces. The mean particle diameter of the emulsions increased dramatically with the rise of chitosan concentration from 0 to 0.33 wt %, indicating the formation of large aggregated structures. At chitosan concentrations above 0.33 wt %, the mean particle diameter of emulsions decreased and reached a minimum value of 0.79 mum at a chitosan concentration of 0.5 wt %. Dynamic oscillatory shear tests indicated that the viscoelastic behavior could be enhanced by the adsorption of chitosan onto the SSPS-coated droplet surfaces. Chitosan concentration had a significant (p < 0.05) impact on the stability of beta-carotene. The least degradation occurred in the emulsion with chitosan concentration of 0.5%. These results implied that the physicochemical stability of beta-carotene emulsions has been improved by the adsorption of chitosan.