Contribution of phosphorylation modification by sodium tripolyphosphate to the properties of surimi-crabmeat mixed gels

Abstract

The effect of sodium tripolyphosphate (STP)-induced chemical phosphorylation on mixed gels formed by surimi-crabmeat was investigated to study the means of improving the quality of surimi products from the perspective of protein phosphorylation. When the STP addition amount was low (≤0.6 g/100 g), the degree of protein phosphorylation in surimi-crabmeat increased. The breaking force, deformation, water holding capacity and moisture distribution of surimi-crabmeat protein gel with a P/T ratio (Ratio of the intensity (P) of protein bands stained with Pro-Q diamond to the intensity (T) of protein bands labeled with SYPRO Ruby) of 8.35 ± 0.07 were considerably enhanced when compared to the control group. The soluble peptide content of trichloroacetic acid increased first and then dropped with increasing STP amount, which opposed the changing trend of disulfide bond content. Less crosslinking of the myosin heavy chain was observed. The α-helix content reduced while the β-turn content increased in the phosphorylated protein of mixed gels. With the participation of a little amount of STP and NaCl, the gel surface was smoother, denser and more continuous, according to scanning electron microscopy observations.