Effects of deheading and rinsing pretreatment on the quality of white leg shrimp (Litopenaeus vannamei) surimi based on endogenous proteases.

In this study, the effects of different pretreatments on the quality of white leg shrimp surimi were investigated based on shrimp endogenous proteases. The results showed that removing the head and rinsing significantly (P < 0.05) improved the gel strength, texture, whiteness, water distribution, and microstructure of the shrimp surimi gels. Headless shrimp surimi (HSS) had higher salt-soluble protein and lower water-soluble protein than whole shrimp surimi (WSS). The shrimp heads had high cathepsin B, L, D, and serine protease activities. Electrophoretic analysis revealed significant degradation of the myofibrillar proteins in the WSS during cold storage and thermal gelation. Moreover, the myosin heavy chains almost disappeared after thermal gelation, and new bands appeared at about 270 kDa and 100 kDa. However, rinsing reduced the endogenous proteases, water-soluble proteins, and concentrated salt-soluble proteins in the shrimp surimi; thus, the quality of the shrimp surimi gel improved after rinsing. These results suggest that the quality of the surimi gel was damaged by the endogenous proteases, and that removal of the shrimp heads and rinsing significantly (P < 0.05) improved the quality of the shrimp surimi gel. The gel properties of WSS were similar after the second rinse to those of unrinsed HSS. The choice of headless shrimp or whole shrimp as the raw material for production needs to be comprehensively considered according to the planned cost and the quality required for the shrimp surimi product. The recommended number of rinses is 1-2.