Chemical changes and shelf-life of conventional surimi and proteins recovered using pH change method from common carp (Cyprinus carpio) muscle during 5 months storage at -18ºC

Chemical changes and shelf-life of common carp (Cyprinus carpio) surimi prepared by conventional washing method and solubilization by acid and alkali processes were investigated during 5 months of storage at -18 °C. Results showed that surimi produced with acid and alkaline solubilization is significantly higher yield than the conventional surimi. Protein solubilization by using acid and alkaline process was high compared with conventional method during storage in freezer except in the first month. Gel electrophoresis patterns showed a significant difference in hydrolyzing of myosin and actin proteins that was observed with increasing storage time. Surimi samples prepared by conventional method indicated more hydrolization, especially in the light chain of myosin during frozen storage. Evaluating the color characteristics (L*, a*, b*) of surimi samples showed that protein produced by using of pH 11 has the highest lightness after conventional surimi. Also, more whiteness in surimi prepared by conventional method was due to effective removal of myoglobin during washing. At zero month, total fat in the surimi samples prepared with acid and alkaline process was low than the surimi samples prepared by conventional method that it can intent to shelf-life increase and health of the product during storage.