Vitamin A, particularly all-trans retinol is excellent for anti-aging but is sensitive to oxygen, heat and light and has low solubility in water. In this study, retinol was encapsulated within oil-in-water (O/W) emulsion, protein-based particle and cycloamylose(CA). And then, it confirms that retinol contained in each delivery system is stable to UV, pH, and temperature and finally measures bioaccessibility. O/W emulsion was compared according to the type and concentration of emulsifier. UV stability of retinol increased with increasing oil concentration. More than 10 wt% of oil was required to maintain stable retinol (50% residual after 24 hours of irradiation). Using anionic emulsifier, retinol had unstable storage stability regardless of oil concentration and temperature. Protein based particle was compared according to the type of stabilizer and polysaccharide. UV stability of retinol was highest in pectin-coated particles. However, 20% retinol remains after 6 hours of irradiation and is vulnerable to UV compared to other delivery systems. In pH stability, pectin-coated particles also stably retained retinol. Inclusion complex of retinol and CA was compared according to the concentration of CA. When CA was used, the residual amount of retinol to UV was high (50% residual after 24 hours of irradiation) regardless of the concentration of the host molecule. In the case of storage stability, retinol remained significantly higher regardless of temperature when cycloamylose was used. It was finally confirmed bioaccessibility each of retinol delivery system. O/W emulsion was determined by emulsifier type, protein-based particle by coating agent, and inclusion complex by CA concentration. All O / W emulsions retained more than 50% retinol, protein based particles retained more than 80% retinol, and inclusion complex retained more than 70% retinol. The bioaccessibility of pure retinol is about 20%. This study provides important information for designing effective delivery systems for improving the stability of retinol.

Retinol is a type of vitamin A that helps the skin's epidermal cells maintain their original function and plays an important role in visual acuity. However, retinol cannot simply be incorporated into foods in its pure form because of limited solubility and chemical instability. In this study, retinol was encapsulated within lipid droplets of oil-in-water (O/W) emulsion and the photo stability of retinol loaded in O/W emulsion was examined. O/W emulsions containing retinol were prepared using Tween 20, Decaglycerine myristate and WPI, respectively, at different oil concentrations (0.1, 0.5, 1.0, 2.0, and 4.0 wt%). Photo stability of retinol was determined by measuring retention rate (%) of retinol loaded in O/W emulsions after exposure to UV light for 24 h and compared to that of retinol dissolved in ethanol. The retinol retention rate was higher for O/W emulsions than retinol in ethanol and the retention rate increased as the oil concentration of emulsions increased, which might be attributed to the opaqueness of emulsions. As the oil concentration of emulsions increased, the turbidity of emulsions also increased. In terms of the type of emulsifier, decaglycerine myristate-stabilized emulsion had the highest retinol retentions rate than other emulsifier-stabilized emulsions after exposure to UV light. This study provides important information for designing effective emulsion-based delivery systems for improving the stability of retinol.