Improvement of thermal and UV-light stability of β-carotene-loaded nanoemulsions by water-soluble chitosan coating.

β-Carotene is a vitamin A precursor and antioxidant with well-known health benefits; however, it is unstable and poorly soluble in water. In this study, β-carotene-loaded nanoemulsions (BC-NEs) and water-soluble chitosan-coated BC-NEs (WSC-BC-NEs) were prepared to improve the stability of β-carotene against high temperature and UV-light. WSC-BC-NEs were round droplets with two distinct layers and an average diameter of 218 nm and zeta potential of +40 mV. The thermal and UV light stability of the WSC-BC-NEs were improved compared to those of both free β-carotene and BC-NEs. Free β-carotene degraded readily during storage, particularly when exposed to high temperature and UV light. By contrast, the WSC-BC-NEs retained 82.0% of β-carotene after 21 days of storage at 37 °C, and 77.6% after 21 days of UV light exposure (253 nm) at room temperature. Furthermore, compared with the BC-NEs, the WSC-BC-NEs improved the thermal stability of β-carotene by about 45.1% after 21 days at 37 °C, and by 28.6% after 21 days of UV light exposure (253 nm). Therefore, the WSC-BC-NEs effectively increased the stability of the encapsulated β-carotene, and show potential for application in the food and beverage industries.