Although the inferior protein bioavailability of purely plant-based meat alternatives relative to animal-derived meats is well-established, the digestion and absorption characteristics of hybrid animal-plant protein products formulated through partial substitution remain poorly characterized. To address this, the hybrid surimi/plant protein (HSP) gels crosslinked by transglutaminase (TGase) with uniform gel strength were prepared by modulating TG dosage (wheat: 18 U/100 g surimi; soybean and rice: 9 U/100 g; pea: 6 U/100 g). In vitro gastrointestinal digestion revealed no significant differences (P > 0.05) in protein or dry matter digestibility (61.50%-69.15%) across groups. However, the legume-based composites (soybean and pea) exhibited significantly higher digestion rate constants (k = 0.029 min⁻¹) than cereal-based composites (k = 0.024 min⁻¹), alongside reduced half-digestion times (t_0.5 = 163.3 min vs. 170.9 min), indicating enhanced digestibility. Particle size distribution analysis showed a significant reduction (P < 0.05) in pea protein gel particle size after pepsin digestion, whereas wheat protein gels retained larger residual particles (D₅₀ = 27.48 μm) post-pancreatin digestion, suggesting greater hydrolytic resistance. Electrophoresis confirmed digestion products were predominantly <20 kDa fragments. Notably, pea protein digests exhibited potent antioxidant activity, strongly correlated with six high-abundance antioxidant peptides identified by mass spectrometry: TLEDQLSEIK, VLNAGVIPEGQF, DAGDGVTHNVPVYEG, VGLLHSQNTSL, LASLYPAVVEDTTK, and LLVVPQNF. Collectively, partial plant protein substitution conferred favorable protein digestibility and nutrient acquisition potential to hybrid surimi gels, with pea protein emerging as particularly valuable for enhancing nutritional functionality in meat-reduced formulations.

Soy β-conglycinin (7S)-dextran conjugates prepared under dry-heating conditions were used to encapsulate curcumin, and the antioxidant activity and sustained-release property of encapsulated curcumin were investigated. Results showed that the grafting degree and browning index of 7S-dextran conjugates increased with increasing reaction time (0, 24, 48 and 72 h), reaching the highest values of 15.02% and 0.24 at 72 h, respectively. 7S-curcumin and 7S-dextran-curcumin nanocomplexes were fabricated by pH-shifting method. The highest curcumin loading of 129.61 μg/mg was observed in 7S-dextran conjugate obtained at 72 h of reaction time (7S-dextran-72 h), which was significantly higher than that in 7S (69.06 μg/mg). Fluorescence spectroscopy indicated that curcumin combined with 7S or 7S-dextran-72 h mainly through hydrophobic interactions. It was observed by transmission electron microscopy (TEM) that 7S-curcumin and 7S-dextran-72 h-curcumin nanocomplexes were spherical. The antioxidant activity of 7S-dextran-72 h-curcumin, which had stable sustained-release property, was approximately 2.36 times higher than that of free curcumin at 100 μg/mL. The bioavailability of curcumin encapsulated in 7S-dextran-72 h was 66.83%, while the bioavailability of curcumin encapsulated in 7S and free curcumin were 48.93% and 33.06%, respectively. 7S-dextran-72 h could be used as an outstanding nanocarrier for curcumin to enhance its antioxidant activity and sustained-release property.