| Starch and hydrocolloid are the main exogenous additives in surimi products.However,the effect of the combination of different starch and hydrocolloid on the gel properties of surimi has rarely been reported,and its synergistic effect is not yet clear.Therefore,the effects of different modified cassava starch and hydrocolloid on the gel properties,rheological properties,thermal stability,chemical forces,protein conformation and microstructure of silver carp surimi were analyzed in this paper.And then the ratio of starch and hydrocolloid was optimized using the response surface method.The improvement effect of compound on the gel strength of surimi was studied.The main conclusions are as follows:1.The gel strength,content of hydrogen bond,ionic bond and hydrophobic interaction of surimi first increased and then decreased with the addition of cassava starch and modified starch increased.The storage modulus curve of surimi containing starch was similar to that of control group.The water holding capacity of surimi could be significantly improved at different starch concentrations(p < 0.05).Addition of low concentration starch could improve the thermal stability of surimi,and promote the transformation of the surimi protein from the ?-helix to the ?-sheet and the ?-turn structure.The results of protein electrophoresis showed that the cross-linking or aggregation of proteins was not influenced by starch.When 2% of hydroxypropyl starch was added,the gel strength,whiteness,hardness,chewiness,resilience and water holding capacity of silver carp surimi were 3855.43 g·mm,79.85,2520.261 g,1883.116 g,0.494 and 79.41% respectively.Starch could be dispersed more evenly in the gel network structure,so that the three-dimensional network structure of surimi gel became more homogeneous and dense.2.Hydrocolloid had different effects on the gel properties of silver carp surimi.Curdlan gum,gelatin and ?-carrageenan gum could significantly improve the gel strength of surimi(p < 0.05),while xanthan gum decreased the gel strength of surimi.The curdlan gum and ?-carrageenan gum could increase the water holding capacity and whiteness of surimi gel.Xanthan gum would not influence the whiteness of surimi gel,and gelatin reduced the whiteness of surimi gel.The results of chemical interactions showed that hydrophobic interaction was the most,important,followe by hydrogen bond and ion bond.The addition of 0.4% curdlan gum and 0.2% ?-carrageenan gum could significantly improve the gel strength,hardness,adhesiveness and chewiness of the silver carp surimi,and water holding capacity and whiteness values reached the maximum.The gel network structure became denser and the pores were less and evenly distributed.However,the thermal stability of surimi protein system could be significantly increased when 0.4% curdlan gum was added(p < 0.05).3.The optimum concentration of starch and hydrocolloid was determined by response surface methodology,which was 1.36% hydroxypropyl starch,0.44% curdlan gum and 0.22% ?-carrageenan gum,respectively.In the conditions,the gel strength of surimi was 3656.96 g·mm.The gelatinzation of properties of starch was changed by curdlan gum and ?-carrageenan gum.The peak viscosity of hydroxypropyl starch was significantly increased from 2407 cp to 2582 cp,and the setback from 561 cp to 855 cp,while the gelatinization temperature decreased from 65.9°C to 58.15°C,and the regeneration value decreased from 1123 cp to 270 cp.The gel strength,water holding capacity and whiteness of the surimi added with starch and hydrocolloid reached the maximum compared with the control group and the single addition group.The texture of the gel was improved,the thermal stability of the surimi system was enhanced,and the hydrophobic interaction of the gel was significantly increased(p < 0.05).The microstructure showed that the dispersity of starch in the network structure of surimi gel was enhanced under the action of hydrocolloid,leading to the network structure of surimi gel became more compact and uniform. |
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