Study On The Properties Of Silver Carp Surimi Gel Induced By Streptoverticillium SK4.001

Silver Carp is the largest yield of freshwater fish species in China. At present, how to improve the utilization rate of Silver Carp processing scale became obstacles the key problem to our country. Processing Silver Carp meat into Surimi Products can fully use the resoures, and enhance its value.Transglutaminase (TGase) is a kind of transferase which can introduces acryl-transfer reaction, it can catalyzes inter- or intra-molecular to form covalent crosslinks in the proteins, make the myosin crossing-linked and improving its gelling property, which is an important index for evaluating surimi products. Therefore, the study of the effect of TGase on Silver Carp surimi gel was an important aspect of our investigations.In this thesis, we have analyzed the Silver Carp nutrition ingredient, studied the effect of different heating processes on gel qualities of Silver Carp surimi. The effect of TGase treatment on gel properties of Silver Carp surimi and the best craft was also investigated, the physico-chemical changes during the formation of surimigel was established.Besides, the quality changes of the products during storage were also studied.The result of different heating processes treating on Silver Carp surimi was observed that two steps heating can obviously increase the gel strength of Silver Carp surimi than one step one. The gel strength of different samples which handed for different heating temperatures and times were determined. Firstly heated at 40℃for 60 minutes, then at 85℃for 30 minutes was the optimal parameters of heating process in the Silver Carp surimi Products. The transglutaminase (TGase) was added in the silver carp surimi to improve the quality.The effect of transglutaminase concentration, handing time, handing temperature and pH on hardness, springiness, cohesiveness, resilience, white degrees and water-holding ability was researched. The result showed that the addition of TGase at different concentrations could improve the hardness,springiness, cohesiveness of silver cap surimi gels distinctly without obvious effect on color and whiteness. The appropriate adding condition of TGase confirmed by orthogonal test was TGase concentration 0.3%, handing time 60min, temperature 40℃and pH7.5.SDS-polyacrylamide gel electrophoresis and solubility analyses indicated that myosin heavy chain (MHC) of silver carp surimi gels could form covalent cross-linking under the catalysis of TGase added. The result of physico-chemical changes showed that hydrophobic interactions, non-disulfide covalent bonds and disulfide bonds were the main protein conformations maintaining the structure of surimi gel from Silver Carp. During the formation of surimigel, total sulphydryl content and reactive sulphydryl content decreased significantly, however, surface hydrophobicity and turbidity increased markedly.Silver Carp surimi and surimi with TGase after the appropriate condition stored at 4℃was investigated. The moisture content, white degrees, texture and TBA value had all changed in a narrow range. The surimi with TGase had changed smaller, which indicated the addition of TGase could make a better storage effect.