Subcritical water-induced soy protein isolate nanofibrils with tailored interfacial architecture enhance the stability and intestinal release of resveratrol-loaded Pickering emulsions

In the present study, subcritical water treatment (SWT) was employed to precisely regulate the fibrillation of soy protein isolate (SPI), and a stable resveratrol-loaded Pickering emulsion was subsequently constructed using the resulting SPI nanofibrils. The effects of different processing temperatures (105, 110, 120, 130, 140°C) and treatment times (20, 30, 40, 50, 60 min) on the structural and functional properties of SPI nanofibrils were investigated. The results showed that treatment at 120°C for 40 min represented the optimal processing condition. Under these conditions, the protein nanofibrils showed a regular short rod structure, the smallest particle size (about 369 nm), and the ζ-potential was approximately −25 mV. Compared with the conventional hydrothermal method (85°C for 12 h), SWT markedly shortened the fibrillation time while improving fibrillation efficiency. The Pickering emulsion stabilized by subcritical water (SW)-induced SPI nanofibrils showed excellent encapsulation performance for resveratrol, with an encapsulation efficiency (EE) of approximately 91%. In vitro digestion experiments showed that the delivery system effectively inhibited the premature release of resveratrol during the gastric phase and achieved controlled release in the small intestine stage. The delivery system significantly improved the recovery rate of resveratrol (about 80%), which was markedly higher than that of the hydrothermal control (about 58%). Release kinetic modeling demonstrated that the release behavior of resveratrol at different digestion stages followed different mechanisms. This study proposes a possible mechanism by which SWT-induced SPI nanofibrils stabilize the oil–water interface and modulate resveratrol release, based on experimental intermolecular force quantification, Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and release kinetics. These findings provide a promising strategy for developing an efficient delivery system based on plant protein.