Formulation of Controlled Size PUFA-Loaded Oil-in-Water Emulsions by Microchannel Emulsification Using β-Carotene-Rich Palm Oil

Abstract

The purpose of this research was to produce size-controlled polyunsaturated fatty acids (PUFA)-loaded oil-in-water (O/W) emulsions using refined palm oil rich in β-carotene, by microchannel (MC) emulsification. A commercial mixture of long-chain PUFA extracted from Menhaden oil was added to palm oil at a concentration of 45 g/L and used as the to-be-dispersed phase. The continuous phase consisted of a water dispersion of two different emulsifiers, in order to improve droplet stabilization and β-carotene bioavailability: sucrose laurate and β-lactoglobulin (1 wt %, respectively). The effect of various levels of to-be-dispersed phase flux (Jd) (10, 20, 40, and 80 L/(m2·h)) and continuous phase flow velocity (V̅c) (ranging from 0.23 to 2.33 mm/s) on the behavior of droplet formation, average droplet size (dav) and coefficient of variation (CV) were evaluated. The fine carotenoid O/W emulsions loaded with PUFA were prepared using an MC emulsification device. Protein-stabilized monodispersed PUFA-loaded emulsions were successfully produced, with a dav of 27.9 μm and a CV of less than 4%. The dav and CV increased with Jd especially above 40 L/(m2·h), and were independent of V̅c, within the velocity range applied in this study. Analysis of the dimensionless Ca indicated that on increasing the Jd up to the critical Ca (0.075), the flow is based on spontaneous transformation, resulting in monodispersed droplets. If Ca exceeds the critical value, viscous force is dominant, the flow is similar to laminar flow, and the to-be-dispersed phase flows out continuously from the MC.