Microencapsulation of high loaded algae oil powders: Spray drying of electrostatic self-assembled emulsion stabilized by SPI and cellulose nanocrystals

To address the problem of low algae oil utilization in the food industry, the researchers prepared algal oil powder with high loaded content (62 %) and stable encapsulation (75 % encapsulation efficiency) by using soybean isolate protein (SPI), cellulose nanocrystals (CNCs), type A gelatin (AG, pI = 7–8) and sodium hexametaphosphate (SHMP). Meanwhile, characterized the properties of the emulsions and the physical indicators of the oil powder. Study shown that the formed CNCs-SPI composite improved the rheological properties and charge intensity (−35 mV) of the emulsion. After adding AG and SHMP to the CNCs-SPI stabilized emulsion, the electrostatic self-assembly of the wall materials were achieved by utilizing the differences in charge properties between particles. The results of Fourier transform infrared spectroscopy indicated that these colloidal particles were composited through hydrogen bond and electrostatic interactions. Compared with SPI oil powder, these polyelectrolyte particles significantly improved the structure of the oil powder after spray drying. Through the formation of a dense and complete encapsulation, it not only reduced the surface oil content by 42.28 %, but also increased the glass transition temperature by 30.85 %. This study provides a feasible method for the preparation of high loaded oil powders and offers a new strategy for emulsion microencapsulation.