Effect of high pressure treatment on rapeseed protein microparticle properties and gastrointestinal release behavior of the encapsulated peptides

ABSTRACT This study investigated the high pressure (HP) modifications of rapeseed protein isolate (RPI) to improve its functional properties as wall materials for rapeseed peptides (RPs) microencapsulation by spray-drying. Results indicated that the surface hydrophobicity of HP-treated RPI microparticles was increased at 400 MPa and 5–15 min but decreased when extended to 20 min. Microparticles obtained with HP-treated RPI showed lower spray-drying yield than native RPI microparticles (67 ± 1.0% and 73 ± 1.4% respectively). Conversely, HP-treated RPI (400 MPa, 15 min) formed microparticles that enabled significantly higher encapsulation efficiency of up to 94.7 ± 1.8% (91.4 ± 1.4% for control samples). Morphological characterization indicated that microparticles with 6.1–8.5 μm diameters were spherical without fissures or cracks. Release profiles revealed that the core of microparticles (especially the 400 MPa, 15 min) achieved controlled release without an initial burst when exposed to the simulated intestinal environment; meanwhile they were resistant to gastric release-stimuli, such as extremely low pH and pepsin.