Different strategies are studied to incorporate lipid-soluble bioactive molecules into water-based food systems. However, these systems solely cannot protect the core compound through the storage period, especially when the core is exposed to environmental stress factors. Water soluble fraction of the crude extract from Enteromorpha prolifera was analyzed for its physicochemical characteristics including chemical composition, structure, rheological and thermal properties. The extract was added to O/W emulsion system containing retinol and stabilized with Tween 20, WPI and sodium caseinate to improve storage stability through different modes of action; as a chelator of metal ions and as a scavenger of radicals. Storage stability was mainly determined by zeta potential, particle size distribution, and retinol retention. The water-soluble extract of E.prolifera mainly consisted of anionic polysaccharide, while impurities of protein, mineral and other pigments were present. Mode of action analysis showed that the extracts had both ferrous ion chelating ability(EC50=0.67%) and free radical scavenging ability(EC50=0.23%), indicating a multifunctioning mechanism of the heterogeneous extract. Addition of extract (0.1%~1% in total emulsion) did not affect the physical stability during 1 week storage. Protective materials are often added to food systems to improve the stability of core materials but excessive use of additives may be repulsive to consumers. In contrast, the optimum concentration range of E.prolifera extract is much lower compared to that of conventional usage of other materials and has lower toxicity to that of strong chelators while providing effective protection.

This study was performed to find the effect of Enteromorpha prolifera as a biosorbent on the removal of heavy metals such as lead, copper, zinc and cadmium from the synthetic wastewater. The biosorption experiment was conducted using biomass of dried Enteromorpha prolifera, which has caused environmental pollution issues in oceans and lakes. To find the physico-chemical characteristics and adsorption capacity, parameters such as biosorbent dosage, initial heavy metal concentration, pH value of solution, contact time which influence the effects on heavy metals removal were changed and the optimum values were found through batch test. The experimental results showed that the sequence for adsorption capacity of heavy metals by Enteromorpha prolifera was Pb2+> Cu2+> Cd2+> Zn2+. The optimum conditions of pH, contact time and dosage of biosorbent were pH 5.0, 60 min. and 0.5 g/L, respectively. As initial heavy metal concentration increased, the adsorption capacity increased up to 17.53 mg/g for Pb with 98% removal efficiency. From the adsorption thermodynamic and kinetic analysis, the biosorption pattern of Pb, Cu, Zn and Cd was well described using Freundlich and Langmuir sorption isotherm with their R2 values of 0.99 and 0.97, respectively. The sorption kinetics followed pseudosecond order kinetic models and thus supported chemical sorption rather than internal diffusion. The work clearly indicates the potential of using Enteromorpha prolifera as an excellent adsorbent for heavy metal removal in industrial wastewater.