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.

• Heesoo Park(Center for Food and Bioconvergence, Department of Biosystems and Biomaterials Science and Engineering, Seoul National University, Seoul, Republic of Korea)
• Saehun Mun(Center for Food and Bioconvergence, Department of Biosystems and Biomaterials Science and Engineering, Seoul National University, Seoul, Republic of Korea)
• Yong-Ro Kim(Center for Food and Bioconvergence, Department of Biosystems and Biomaterials Science and Engineering, Seoul National University, Seoul, Republic of Korea)