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 β-carotene oil-in-water (O/W) emulsions. The β-carotene (O/W) emulsions were prepared by combining 95 wt% UFP (1–5%, wt/wt) solutions with 5 wt% soybean oil containing β-carotene (0.05 wt% in the final emulsion). The stability of β-carotene emulsions was evaluated by droplet size and distribution, viscosity, zeta-potential, visual phase separation, light microscopy imaging and β-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, 2]) less than 1.0 μm, 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 β-carotene emulsions when compared to other commercial polysaccharides, including gum Arabic and beet pectin.