Solid lipid nanoparticles enhance the resistance of oat-derived peptides that inhibit dipeptidyl peptidase IV in simulated gastrointestinal fluids
Lijing Su, Fa Zhou, Mengru Yu, Rui Ge, Jiatai He, Bo Zhang, Yanyan Zhang, Junfeng Fan
Abstract
In this study, we investigated the effects of solid lipid nanoparticle (SLN) nanocrystallization on the stability of two fractions of oat globulin-derived peptides. i.e., OGL, with molecular weight (MW) < 3 kDa, and OGH, with MW 3–10 kDa, in simulated gastrointestinal fluids (SGF). Both fractions were effectively encapsulated in SLNs with similar encapsulation efficiencies, zeta potentials and storage stability, but the particle sizes of each fraction, their polydispersity indices and thermogravimetric properties differed. The encapsulated peptide fractions had different rates of release and degradation in SGF, but both fractions could be protected from secondary hydrolysis, and both maintained high bioactivity rates when they encountered the SGF. Results from infrared spectroscopy and X-ray diffraction revealed that OGL had high binding affinity for the SLN–OH group and a high degree of crystallinity, which ensured its stability in SGF. These findings contribute to the delivery-system design for the encapsulated peptides with improved functional attributes.