The formation mechanism of self-assembly composite gels

This study constructed a self-assembled Soy protein isolate-Ficus awkeotsang Makino pectin (SPI-JFSP) composite gel and elucidated its gelation mechanism. Results demonstrated that increasing the JFSP mass ratio (SPI/JFSP from 4:0 to 3.4:0.6) led to increased aggregate sizes in the pre-gel solution (from 367.05 ± 5.42 nm to 2088.90 ± 21.46 nm), accompanied by a conformational transition of SPI from β-sheet to α-helix and β-turn. Atomic force microscopy (AFM) revealed that JFSP bridged SPI aggregates through flexible pectin chains at low concentrations (<0.2 %, w/v), while forming a continuous polysaccharide network encapsulating protein aggregates at high concentrations (>0.2 %, w/v). Dynamic rheological and texture analyses indicated a transition from viscous fluid (G'' > G′) to elastic gel (G′ up to 706 Pa) upon JFSP incorporation. Isothermal titration calorimetry (ITC) confirmed that hydrophobic interactions dominated the gelation process (ΔH 1141 kJ/mol, ΔS = 46680 kJ/mol), eliminating the need for traditional chemical modification or thermal stimulation. This work provides a novel strategy for constructing self-assembled polysaccharide-protein composite hydrogels.