MICROENCAPSULATION OF BETA-CAROTENE: CHARACTERIZATION, IN VITRO RELEASE, AND BIOAVAILABILITY by ERIK GLENN DONHOWE

Beta-carotene is the main dietary source of Vitamin A, an essential micronutrient required to maintain proper health. The in vivo bioavailability and absorption of beta-carotene, however, is limited due to the inhibition by the natural plant matrices in which it is found. This study focused on microencapsulation methods to improve release and bioavailability in vitro. Alginate and chitosan formulations were evaluated for encapsulation efficiency and particle size, and the effect of viscosity on release in vitro were determined. Increased viscosity decreased release due to inhibition of diffusion from the microcapsules. Additional research compared the in vitro bioavailabilities and physical properties of three types of microencapsulated betacarotene (spray-dried with maltodextrin, commercial water-dispersible, and chitosan-alginate microcapsules) in terms of morphology, water activity, moisture content, particle size, surface beta-carotene, and encapsulation efficiency. The bioavailability of the commercial waterdispersible beta-carotene was consistently highest, even in the presence of food matrices (yogurt, pudding). INDEX WORDS: Beta-carotene, microencapsulation, in vitro digestion, bioavailability MICROENCAPSULATION OF BETA-CAROTENE: CHARACTERIZATION, IN VITRO RELEASE, AND BIOAVAILABILITY