Stability and Bioaccessibility of β-Carotene in Nanoemulsions Stabilized by Modified Starches

Oil-in-water nanoemulsions stabilized by food-grade biopolymer emulsifiers (modified starches) were fabricated using high-pressure homogenization in an effort to improve the stability and bioaccessibility of beta-carotene. Physicochemical and biological properties of beta-carotene nanoemulsions were investigated considering the particle size, beta-carotene retention, and in vitro digestion. During 30 days of storage at different conditions, the mean diameters of the emulsion systems were increased by 30-85%. The retention of beta-carotene in nanoemulsions was significantly higher compared to that of the beta-carotene dispersed in bulk oil. After in vitro digestion, the bioaccessibility of beta-carotene was increased from 3.1% to 35.6% through nanoencapsulation. The results also indicated that modified starch with high dispersed molecular density led to a higher retention but lower bioaccessibility of beta-carotene in nanoemulsions. This could be due to the thick and dense interfacial layer around the oil droplets. This result provides useful information for developing protection and delivery systems for carotenoids.