Study On The Preparation And Properties Of Grass Carp Surimi With Acidic And Alkaline Treatments

The surimi from grass carp was produced using three washing cycles, acidic and alkaline treatments. The effects of acidic and alkaline treatments on the physicochemical properties of surimi from whole gutted grass carp were studied, including texture properties, dynamic rheological properties, color properties, thermodynamic properties and protein composition properties. Meanwhile, in order to improve the quality of surimi gel, TG enzyme,potato starch, soybean oil and peanut oil were added to grass carp isolate protein with alkaline treatment. At last, the different storage stability of surimi with different treatment methods was investigated, which will give technical and theoretical suggestions to surimi industry.The results were as follows:1. The solubility of grass carp muscle protein was lowest at pH5and highest at pH3on the acid side and at pH12on the alkali side.2. The pH treatment (pH3,12) can significantly increase the protein yield and fat reduction, and alkaline treatment had higher protein yield than acid treatment.3. Myosin heavy chain was slightly degraded during acidic and alkaline treatments, which would not affect greatly surimi quality.4. Alkaline treatment and three washing cycles yielded higher breaking force and deformation than acid treatment, exhibiting more disulfide formations. Lower TPA value was observed in the surimi prepared with acid treatment.5. The grass carp muscle proteins treated with acidic and alkaline showed different dynamic rheological properties compared with washing fish muscle proteins. Both myofibrillar and sarcoplasmic proteins underwent denaturation after acidic and alkaline treatment, which was shown in the absence of endothermic peaks through DSC. Alkaline treatment and acid treatment had the same trend.6. Alkaline treatment and acid treatment had bad effects on color of surimi and Acid treatment had better color than alkaline treatment.7. TG enzyme can significantly improve the gel strength, TPA values and dynamic rheological properties of surimi with alkaline treatment. With the increase of TG enzyme adding amount, gel strength, hardness, G, values increased. Moreover, there were better Springiness, cohesiveness, chewiness, resilience at the adding amount of0.6%. Potato starch can significantly increase whitenss values texture and dynamic rheological properties of surimi with alkaline treatment. Soybean oil and peanut oil can significantly improve whiteness value of surimi with alkaline treatment. However, there was an adverse effect on gel strength, hardness, chewiness.8. There was a certain amount of protein and fat oxidation for surimi with different treatments. Larger degree of oxidation was observed in surimi with washing treatment compared with other treatments. Moreover, there was a certain degree of microbial corruption during storage, which was not significant. Gel strength and TPA values slightly decreased during storage and surimi with three washing cycles resulted in larger degree of decline in gel strength, hardness, chewiness compared with those treated with other methods.