Changes in protein compositions and their effects on physical changes of shrimp during boiling in salt solution

Dried shrimp is a high-value fishery product of Thailand. Boiling shrimp in salt solution is an important step during the production of dried shrimp and affects significantly the quality of dried shrimp. However, not much information is so far available on the effects of various boiling parameters on the quality changes of shrimp, especially in terms of the changes of shrimp protein compositions and their consequences on microstructural and physical changes of shrimp. The present work was thus aimed at studying the effects of boiling time and concentration of salt solution on the protein fractions, microstructural and physical changes of boiled shrimp. In addition, the relationships between protein compositions, cooking loss, texture and microstructure of shrimp were established using coupled image and fractal analysis. Boiling was investigated at various concentrations of salt solution and boiling times. Boiled shrimp was then evaluated in terms of its protein fractions, microstructure in terms of fractal dimension and physical changes (cooking loss and hardness). The relationships between all studied parameters were monitored and simple correlations between them were determined. The changes of cooking loss, hardness as well as the normalized changes of fractal dimension (ΔFD/FD0) highly correlated with the changes of protein compositions of shrimp.