Effects of soybean dietary fiber on gel properties, protein conformation and volatile compounds of low-salt surimi

This study investigated the effects and potential mechanism of soybean dietary fiber (SDF, 0–1.2 %, w /w) on the gel properties and fishy volatile compounds of low-salt silver carp surimi (1.25 % NaCl). The results showed that at an appropriate level (0.3 % or 0.6 %), SDF in surimi promoted the formation of hydrophobic interactions and disulfide bonds, facilitated the β-sheet transition, and served as a filler within the gel network, leading to a more compact and denser network of a surimi gel. Excessive SDF competed with proteins for water, leading to SDF aggregation and volume exclusion, thereby generating a denser but incomplete gel network. Compared with the control group, the strength of surimi gels with 0.3 % and 0.6 % SDF was increased by 11.92 % to 20.02 %, while the corresponding water-holding capacity increased to 85.83–86.49 % and the free water content decreased by 30.10–41.75 %. Moreover, the total content of fishy volatile compounds decreased by 7.29 % to 13.80 %. Correlation analysis revealed that the seven identified fishy volatile compounds (hexanal, heptanal, octanal, nonanal, decanal, 1-octen-3-ol, and 1-hexanol) were negatively correlated with gel strength, water-holding capacity, immobile water, and hydrophobicity of the protein surface.