Preparation and characterization of Pickering emulsion gel stabilized by WPI/SPI composite particles and encapsulation of milk-derived peptide FDRPFL

In this study, Pickering emulsion (PE) stabilized by whey protein isolate/soybean protein isolate (WPI/SPI) composite particles were used as a template to construct Pickering emulsion gel (PEG). The results showed that the PE stabilized by WPI/SPI composite particles had good centrifugal and storage stability at 4 °C (at least 4 months). Furthermore, When SA concentration was 3% and PE:SA ratio of 5:1, the obtained PEG with water-in-oil type exhibited a smaller droplet size, a denser network structure, and solid-like behavior in the linear viscoelastic region using a laser particle size analyzer, rheometer, and confocal laser scanning microscopy. Moreover, the increase of hydrogen bonds after SA addition confirmed that increased of β-sheet in WPI/SPI by Fourier-transform infrared spectroscopy, as β-sheet structure was stabilized by interchain hydrogen bonds, thus forming a denser network structure. In addition, PEGs could effectively encapsulate peptide FDRPFL, with a highest encapsulation efficiency of 72.8%. In vitro digestion behavior revealed that PEGs could improve the bioaccessibility of peptide FDRPFL and mainly followed the release mechanism of non-Fickian superstate II. Taken together, the present findings provide a theoretical framework for the development and application of PEGs stabilized by WPI/SPI composite particles.