Shi Wenzheng

Studies on the protein structure and characteristics of gel strength of Parabramis pekinensis surimi.

Protein plays an important role in the gel-forming of surimi. The effects of protein structure on the gel formation of surimi were studied through the changes of myosin chemical interactions and laser Raman spectroscopy during the Parabramis pekinensis surimi storage. The results showed that the myosin contents, ionic bonds,hydrogen bonds and hydrophobic bonds of surimi decreased fast at first and then slowly as well as the changes of gel strength during storage at the temperature of - 80 ℃ and - 20 ℃. The myosin contents, ionic bonds and hydrogen bonds of surimi declined directly during storage at the temperature of 0 ℃ and 5 ℃, while the hydrophobic bond increased at first and then decreased. Thus,It can be concluded that myosin contents,ionic bonds and hydrogen bonds play important roles in maintaining the complex high-level structure of surimi. According to the Laser Raman spectroscopy, α-helix structure is the major conformation maintaining protein network structure of Parabramis pekinensis surimi. Part of α-helix of myosin changed into random coil structure during the storage. When α-helix structure turned into random coil partly,the hydrophobic residues embedded in myosin molecules were exposed to the surface of molecules as the protein denatured. The higher the storage temperature,the more content of random coil structure and the greater the degree of protein denaturation,which reflected in the gel strength decreased more. The study of surimi protein structural changes during the storage of surimi clarifies the formation mechanism and the prevention of surimi protein denaturation significantly. The correlation of surimi myosin chemical interactions,protein secondary structure and the ability of surimi gel-forming could be continued in the future research.