Physical and chemical stabilities of β-carotene emulsions stabilized by Ulva fasciata polysaccharide

The objectives of this study were to investigate the effect of Ulva fasciata polysaccharide (UFP) on the physical and chemical characteristics of beta-carotene oil-in-water (O/W) emulsions. The beta-carotene (O/W) emulsions were prepared by combining 95 wt% UFP (1-5%, wtiwt) solutions with 5 wt% soybean oil containing beta-carotene (0.05 wt% in the final emulsion). The stability of beta-carotene emulsions was evaluated by droplet size and distribution, viscosity, zeta-potential, visual phase separation, light microscopy imaging and beta-carotene degradation of the emulsions during storage. In addition, the influences of ionic strength and pH on physical stabilities of emulsions were characterized. Emulsions stabilized with high concentration (>2% wt/wt) of UFP had an average droplet size (D [3, 21) less than 1.0 mu m, and the average droplet size significantly decreased until the polysaccharide concentration reached 3%. Light microscopy images and emulsion zeta-potentials demonstrated 3% (wt/wt) UFP to be the optimum emulsifying agent concentration. UFP revealed better emulsifying properties and improved physical stabilities of beta-carotene emulsions when compared to other commercial polysaccharides, including gum Arabic and beet pectin. (C) 2016 Elsevier Ltd. All rights reserved.