Abstract: In order to investigate the effect and underlying mechanism of deacetylated konjac glucomannan (DKGM) on the structure and gel properties of pork myofibrillar protein (MP), the changes in the gel strength, water retention, water distribution, microstructure, secondary and tertiary structures and gel molecular forces of MP were analyzed after the addition of DKGM at different levels (0%, 0.125%, 0.25%, 0.5% and 1%). The results showed that the gel strength of MP increased with the increase of DKGM addition, reaching the maximum at an addition level of 0.25%, which was 1.55 times higher than that of the control group. The addition of DKGM could retard the flow of water, thus improving the gel water-holding capacity. Cold-field scanning electron microscopy revealed that the addition of DKGM could promote the formation of more uniform and dense network structures in MP gels. The structure and force analysis showed that the addition of an appropriate amount of DKGM could promote the unfolding of MP molecules and the exposure of hydrophobic groups, increase the content of active sulfhydryl groups, induce α-helix-to-β-fold transition, enhance the hydrophobic interactions and disulfide bonds of MP gels, and thus improve the gel strength and water-holding capacity.

Key words: myofibrillar protein; deacetyl konjac glucomannan; gel properties; secondary structure; disulfide bonds