The formation mechanism and textural properties of a complex gel based on soybean glycinin-chitosan complex coacervates: Effects of pH, heat treatment temperature and centrifugation.

The soybean glycinin (11S)-chitosan (CS) complex gels with various textural properties were successfully constructed. The process involved the initial formation of 11S-CS coacervates through electrostatic interactions, followed by a heating treatment to obtain the final complex gels. The impacts of pH, heating temperature, and centrifugation on 11S-CS complex gel properties were investigated. The results indicated that the pore arrangement of the gel formed at pH 7.3 was more tightly and uniformly packed than those formed at pH 6.8 and 7.8. Centrifugation facilitated denser and more ordered gel structures at the three pH values, while increasing the heating temperature exhibited the opposite trend at pH 6.8 and 7.8. These structural differences were also reflected in the rheological and textural properties of the gel. The 11S-CS complex gels exhibited an elasticity-based gel property. The textural properties of gels formed at pH 6.8 were stronger compared to those formed at pH 7.3 and 7.8. However, when the 11S-CS coacervates were heated without centrifugation, the resulting gels were weak. This study emphasizes the potential of using protein/polysaccharide associative interactions during gel formation to alter the microstructure of the gel, meeting various production requirements.