Effects of Sodium Citrate, Sodium Tartrate Substitution of Sodium Chloride on the Quality of Squid Surimi Gel

In this study, the squid surimi gel was prepared by sodium citrate (SC) and sodium tartrate (ST) which substituted of sodium chloride (NaCl) in different proportions and the effect of organic salts on the properties changes of squid surimi gel was investigated through rheological properties, physicochemical properties and protein characteristics. From the results, the gel prepared by addition of organic salt and NaCl by the ratio of 2:1 significantly improved (P<0.05) the gel strength, hardness, and water holding capacity compared to other groups. Meanwhile, the elasticity and cohesiveness of surimi gel were consistent with the change trend of surimi gel strength. The mixed addition of organic salts and NaCl inhibited the generation of hydrophobic interactions, and the inhibition effect reached the minimum value of 0.59 g/L (SC) and 0.43 g/L (ST) when the ratio was 1:1. The results of rheological properties demonstrated that the addition of organic salts significantly shortened (40~57 °C to 40~52 °C) the gel degradation due to endogenous proteases during heat process of squid surimi. The secondary structure results showed that the content of α-helix and β-sheet increased when organic salts were added with NaCl, and the relative content of β-turn was significantly (P<0.05) higher than other groups by the ratio of 1:1. The low-field NMR results showed that when the ratio of organic salt and NaCl was 2:1, the gel contained more immobilized water and less free water than the other groups. All results showed that addition of organic salt and NaCl at ratio of 2:1 could keep the high gel quality of squid and provided the scientific basis to prepare the squid products by using organic salts.