Effects Of Broken Methods On Surimi Gel Properties

China is the largest producer of freshwater fish in the world, which is rich in fishery resources. Surimi and surimi products occupy an important position in the fish processing products. Chopping (gringding) is one of the important steps during surimi and surimi products processing, and broken ways and the changes during manufacturing processes affect the gel properties. While the reasons for differences in the characteristics of surimi gel under different broken methods must be researched deep in. In this work, the effects of chopping and beating on surimi gels quality and the reasons of gel quality difference were found through the particle size of fish paste, microstructure, physicochemical properties, and activity of endogenous enzyme were investigated with silver carp as the raw materials. The results were as follows:(1) The influence of different broken methods (chopping and beating) to gel quality were studied. The factors such as chopping speed, chopped time without/with salt had a significant effect on the gelling properties of surimi gel (p<0.05).The optimum process conditions of chopping were obtained:chopped2min without salt and2-4min chopped with salt at1500r/min, the higher the gel strength, WHC and whiteness and lower cooking loss of surimi. Optimum beating conditions:beated5min without salt and beated30min with salt at45r/min, the gel properties of surimi is better. Overchopping impacted the quality of surimi gel severely. Effect of the total chopping time on surimi gel properties is greater than the added salt time. The optimum chopping process to obtain the highest gel qualities was to add salt at the early stage and chopped without salt is important.(2) Changes of surimi particle size and microstructure during the chopping and beating process. The particle size distribution is different under two methods. The particle size of raw surimi paste with salt was greater than without salt. Chopped raw surimi with salt occurred aggregation at the late stage by scanning electron microscopy pictures And beated raw surimi was larger than chopped raw surimi. The microstructure beated raw surimi is orderly at the early stage and smaller pore diameter at the late stage The pore diameter is small and fractal dimension is large when raw surimi and surimi gel chopped4min and beated30min with salt. Compared to chopped surimi gels, beated gels had more uniform, compact microstructure with smaller pore diameter and larger fractal dimension.(3) Study on of denaturation and aggregation of surimi protein during chopping and beating progress. Salt-soluble protein content is decreased and the temperature is gradually increased over chopping and beating time. The rate of content of salt-soluble proteins reduce during chopping is faster than the beating, indicating that the difference of denaturation and aggregation of proteins from chopping and beating. These differences mainly come from the disulfide bond, disulfide bond, hydrophobic interactions, and the change of protein secondary structure. Protein aggregation rely mainly on the disulfide bond, disulfide bond and hydrophobic interaction in the process of chopping; While only hydrophobic interactions involved in aggregation behavior, rather than the disulfide covalent bonds and the disulfide bond during beating progress.(4) The activities of endogenous enzymes were studied during chopping and beating. Chopping and beating had a significant effect on the activities of cathepsin L (p﹤0.05).The activities of cathepsin B and L showed a decreased trend and the activity of cathepsin L is higher than the cathepsin B. The activity Cathepsin L activity in the process of chopping is larger compared with beating. There is no significant correlation between endogenous glutamine enzyme activity and characteristics of surimi gel.