Effect of chitosan molecular weight on the stability and rheological properties of β-carotene emulsions stabilized by soybean soluble polysaccharides

In this study, beta-carotene emulsions were prepared using a two-stage homogenization process and adsorption of chitosan to anionic droplets coated with soybean soluble polysaccharides (SSPS). Effects of the molecular weights of chitosan on the stability and rheological properties of beta-carotene emulsions were investigated. Results demonstrated that the zeta-potential, particle size and rheological properties of emulsions were greatly dependent on the chitosan molecular weight. It was found that the particle size of SSPS-stabilized emulsions increased with the rise of chitosan molecular weight at higher chitosan concentrations (>0.2 wt%). Chitosan molecular weight had a significant impact on the heat and light stability of beta-carotene in emulsions. SSPS-stabilized emulsion with the adsorption of medium molecular weight-chitosan (MM-chitosan) was more stable than those with the adsorption of low and high molecular weight-chitosan (LM-chitosan and HM-chitosan). Dynamic oscillatory shear tests indicated that the viscoelasticity could be enhanced by the adsorption of higher molecular weight of chitosan onto the SSPS-coated droplet surfaces. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.