Optimizing the encapsulation behavior of egg yolk on DHA by vacuum low-temperature spray drying to improve the hydration properties of the powder

Abstract

A fundamental issue in the design of docosahexaenoic acid (DHA)-enriched egg yolk powder (EYP) is the enhancement of hydration properties, which is an essential criterion for the evaluation of powders with promising 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. 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. The most striking finding of this study was the DHA-enriched EYP prepared by VLTSD exhibited desirable solubility, dispersibility and stability during rehydration, which was well predicted by low-field NMR. 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. This article provided new insights into the improvement of the properties of DHA-enriched EYP, especially the hydration properties.