Abstract: The gel properties and the protein component changes during surimi gel forming of freshwater fishes, Sliver Carp, Bighead, Grass Carp and Crucian Carp, were investigated by assaying the protein components and gel properties and SDS-PAGE electrophoresis. The contents of crude protein in these fish species were not much different. However, the gel strength in surimi gel was obviously different because of the difference in the content of salt-soluble protein. The percentage of salt-soluble protein and water-soluble protein decreased gradually during surimi-based products manufacturing, while that of the insoluble protein increased. Elastic gel formed from meat smashing with salt and formed mainly during low temperature setting. SDS-PAGE pattern showed that the content of myosin heavy chain (MHC) decreased obviously during surimi gel forming, while that of the myosin light chain (MLC) and actin had no change. Transglutaminase (TGase) catalysed the formation of gamma-Glu-epsilon- Lys isopeptide bonds among myosin heavy chain and created the insoluble protein with network structure.

Key words: freshwater fish, protein, myosin heavy chain, gelation