Soy protein isolate emulsion microgel particles for encapsulating oil

Emulsion microgels (EMGs) are a newly developed fat encapsulation system, consisting of one or more emulsion droplets encapsulated in a soft solid in a manner that forms micron-sized particles. Herein, soy protein isolate (SPI) and soybean oil were used to prepare EMGs by shear gelation. EMGs (∼10 μm) were formed and encapsulation efficiencies of up to 99% were achieved by adjusting the oil content and SPI concentration. The size of EMGs produced with 6% (w/v) SPI and 5% (v/v) oil depended on the shear and heating rates. Larger particles (>70 μm) were obtained at low shear (200 s−1) and smaller particles (<20 μm) at higher shear (800 s−1). All EMG systems exhibited shear thinning behavior and the particle size positively corresponded to the heating rate at the same shear rate. In addition, the compactness of the protein network in the SPI gel were improved due to the increased density of the EMG-filled gel's microstructure.