Natural egg yolk emulsion as wall material to encapsulate DHA by two-stage homogenization: Emulsion stability, rheology analysis and powder properties

The use of safe physical means to achieve egg yolk as natural carrier for active ingredients plays an important role in increasing the added value of egg yolk. In this paper, we prepared DHA-fortified egg yolk emulsion using high-speed shearing (HSS) only and HSS combined with high-pressure homogenization (HPH), respectively. HPH reduced particle size and zeta potential, allowing for better emulsion stability. After 14 days of storage, the encapsulation efficiency was 93.88% even with 15% (w/w) algae oil addition. Rheology analysis presented that HPH improve the viscoelasticity, indicating the enhancement of interaction force between droplets. Then, vaccum low-temperature spray drying (VLTSD) was used to produce powder, which allowed for minimal damage to the encapsulation structure according to scanning electron microscopy and the hydration properties of powder was improved. This work provides a new idea for using egg yolk to encapsulate DHA and improving the properties of egg yolk powder.