Fabrication and characterization of double-network meat analogs based on camellia oleosomes and soy protein-wheat gluten induced by transglutaminase and calcium alginate

Plant-based meat analogs often exhibit poor elasticity, limited water-holding capacity, and lack a well-integrated fat-phase, which limits their applications in food industry. This study aimed to introduce camellia seed-derived oleosomes as templates for lipid droplets into textured soy protein-wheat gluten, followed by dual-crosslinking using transglutaminase (TG) and sodium alginate with varying Ca²⁺ concentrations. Results showed that oleosomes inclusion transformed the porous structures of textured proteins into droplet-embedded protein matrices, along with enhanced hardness, increased lightness, and reduced redness. TG induction promoted the ε-(γ-glutamyl)-lysine bonds between oleosomes and continuous-phase proteins, while sodium alginate, reinforced by Ca²⁺, created a robust network structure with smaller pore sizes and more interaction zones that tightly held the oleosomes. The addition of 10-20 mM CaCl₂ significantly increased the immobilized water content, G' values and promoted the transformation of β-turns to β-sheets. According to Lissajous-Bowditch analyses, oleosome-protein meat analog was identified as a soft gel, exhibiting erratic and abrupt changes at strain ≤10 %. In contrast, TG-treated analogs, particularly those with both TG and Ca²⁺, exhibited greater structural elasticity and resistance to large deformations (≤500 %), due to double-network structures with enhanced mechanical strength and reversible deformation resistance. Additionally, double-crosslinked meat analogs significantly influenced the rate of lipid digestion.