Comparative study of oil-in-water emulsions encapsulating fucoxanthin formulated by microchannel emulsification and high-pressure homogenization

Abstract

In this study, we investigated the formulation and stability characteristics of monodisperse oil-in-water (O/W) emulsions encapsulating fucoxanthin using straight-through microchannel emulsification (MCE). Monodisperse O/W emulsions stabilized by hydrophilically modified lecithin (ML), whey protein isolate (WPI), or polyoxyethylene (20) sorbitan monolaurate (Tw20) were stably formulated using straight-through MCE. The resulting emulsions maintained the droplet sizes steadily at 30.3 ± 0.2 μm (ML), 32.3 ± 0.1 μm (WPI) and 29.0 ± 0.8 μm (Tw20) and the relative span factor (RSF) < 0.5 after 30 days storage at 25 °C. The fucoxanthin retention (RTf) in the collected emulsions, decreased from 100% to 44.3 ± 0.1% (ML), 90.7 ± 5.4% (WPI) and 51.4 ± 10.6% (Tw20) after storage. Subsequently, we compared the characteristics of O/W emulsions which were formulated by 1 wt% Tw20 using high-pressure homogenization (HPH) and MCE under the same storage and digestion conditions. After 15 days storage at 4, 25 and 50 °C, all emulsions revealed good physical stability, and there was no drastic change in the droplet sizes. In terms of chemical stability, MCE was pronouncedly better than HPH at the same level of storage temperature. In contrast, the free fatty acids (FFAs) release and fucoxanthin bioaccessibility in emulsions using HPH were significantly higher than MCE. The findings of our study give useful information for food and pharmaceutical industries which express more concern about the natural bioactive compounds for usage.