Effects of soluble soybean polysaccharides on the formation of gel formation of soybean protein isolate

ObjectiveThis study aimed to investigate the effect of soluble soybean polysaccharides (SSPS) on gel formation and properties of soybean protein isolate (SPI).MethodsSPI suspension and gels with different amounts of SSPS were prepared, and SPI suspension and gels without SSPS were used as controls. The structural properties, physicochemical properties and gel properties were determined.ResultsDuring the preparation of SPI into gel, glycosylation reaction occurred between SPI and SSPS, which led to the change of the secondary and tertiary structure of SPI. With the addition of SSPS, the absolute value of zeta-potential decreased and the thermal stability increased. The ionic bond, hydrogen bond, hydrophobic interaction and disulfide bond content of gel decreased, and the covalent bond content of non-disulfide bond increased. When the addition was 10%, the surface hydrophobicity of SPI suspension decreased by 88.42%, the gel hardness decreased by 28.85%, and the water holding capacity increased by 40.72%. The SEM results showed that the addition of SSPS resulted in a loose and porous gel network and a decrease in gel strength.ConclusionThe addition of SSPS in the preparation of SPI gel resulted in glycosylation reaction. With the increase of SSPS addition, the protein structure and gel properties changed more significantly.