O/W emulsion is usually adopted to incorporate lipid-soluble bioactive molecules into water-based food systems. However, the emulsion system solely cannot protect the core compound through the storage period, especially in cases when the core is unstable to environmental stress factors. Wall materials such as maltodexrin and chelators such as EDTA-Na are added to improve the stability of core materials but excessive use of additives may be repulsive to consumers. In this study, water soluble fraction of the crude polysaccharide extracted from Enteromorpha prolifera, a type of green algae commonly found in the southern coast of Korean sea, was added to an O/W emulsion system containing retinol to improve storage stability through different modes of action; as a chelator of metal ions, as a scavenger of free radicals and as a wall material. The radical scavenging ability and chelating ability of E.prolifera polysaccharide were determined in solution state. Particle size, zeta potential and retinol retention rate were measured as stability markers in emulsion. Emulsion stability increased and then decreased as the amount of polysaccharide increased from 1 to 5 mg. This optimum concentration is much lower compared to that of conventional usage of wall materials, therefore less affecting the physical characteristics of emulsion while providing effective protection.

• Sun-Young Park(Center for Food and Bioconvergence, Department of Biosystems and Biomaterials Science and Engineering, Seoul National University)
• Yong-Ro Kim(Center for Food and Bioconvergence, Department of Biosystems and Biomaterials Science and Engineering, Seoul National University)