Optimizing the Encapsulation Behavior of Egg Yolk on DHA by Vacuum Low-Temperature Spray Drying to Improve the Hydration Properties of the Powder.

Due to the poor aqueous solubility of docosahexaenoic acid (DHA), encapsulating it in egg yolk results in a reduction in the hydration properties of egg yolk powder (EYP), subsequently affecting its functional properties. In this study, the effects of vacuum low-temperature spray drying (VLTSD), high-temperature spray drying (HTSD), and freeze-drying (FD) on the hydration properties of DHA-enriched EYP were investigated. Firstly, we optimized the inlet temperature and feed rate for VLTSD (60 °C, 300 mL/h) and HTSD (170 °C, 800 mL/h), while FD was conducted under − 70 °C conditions. The most striking finding of this study was the DHA-enriched EYP prepared by VLTSD exhibited desirable solubility (54.86 g/100 g), water dispersibility (48.63%), and coefficient of stability (24.88%) during rehydration, which was well predicted by low-field NMR. Compared to HTSD and FD, the solubility increased by 16.18% and 45.17%, respectively. Furthermore, at the microscopic level, SEM images and FTIR spectra revealed that VLTSD enhanced the hydration properties by protecting the structural integrity and increasing the hydrogen bonding of the DHA-enriched EYP. The encapsulation efficiency of DHA-enriched EYP prepared by VLTSD, HTSD, and FD were 97.15%, 96.51%, and 81.31%, respectively. According to the quality analysis, VLTSD had the best protection for DHA-enriched EYP in terms of chromaticity, bulk density, storage stability, and sensory evaluation. Therefore, this study confirmed the applicability of VLTSD technology for microencapsulation of bioactive substances such as DHA to enhance the hydration properties of powders. [ABSTRACT FROM AUTHOR]