Ultrasound-assisted transglutaminase crosslinked gluten-peanut protein for efficient encapsulation and controlled release of resveratrol.

A novel wall material was prepared by cross-linking gluten (GLU) and peanut proteins (PP) with transglutaminase under a dual-frequency ultrasound field (U-TG-PP-GLU) and used to encapsulate resveratrol (Res). The microencapsulation process was optimized, and particle size, zeta potential, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), fluorescence spectroscopy, surface hydrophobicity, and in vitro release of Res were evaluated to characterize the performance of the resulting microcapsules. The results showed that under the optimal encapsulation conditions, the encapsulation efficiency and loading capacity reached 97.74% and 8.15%, respectively. The microcapsules exhibited a particle size of 473.9 nm and a zeta potential of -34.49 mV, both smaller than those of the core (5532.4 nm, -25.56 mV) and the wall material alone (1677.5 nm, -21.55 mV). TEM imaging confirmed successful encapsulation of resveratrol within the cross-linked protein matrix. Structural analyses revealed that the embedding process decreased the intrinsic fluorescence intensity of the wall material, increased surface hydrophobicity from 8245 to 55,892 (a.u.), reduced the α-helix content by 38.5%, and increased the β-sheet and β-turn contents by 18.4% and 31.0%, respectively. The cumulative release of resveratrol from the microcapsules after 4 h of simulated gastrointestinal digestion was 62.8%, with a half-maximal effective time (EC₅₀) of 101.75 min. Collectively, these findings indicate that transglutaminase-mediated cross-linking combined with dual-frequency ultrasound treatment enables PP-GLU microcapsules to achieve high encapsulation efficiency and controlled release of resveratrol, offering a promising strategy for encapsulating resveratrol and similar bioactive compounds.