Study on emulsifying properties of salt-soluble proteins from grass carp

Emulsifying properties of fish salt-soluble proteins (SSP) determine the surimi technical qualities such as uniformity and stability.The molecular mass of main compositions of SSP from grass carp were determined using the method of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) .Effects of pH, ironic strength, and the ratio of oil to water volume on emulsifying properties of SSP were studied by single factor and response surface method.The results showed that the molecular masses of myosin heavy chains, two myosin light chains, and actins from SSP were 200, 30, 23, and 40ku respectively.pH and ironic strength were very significant factors which influenced emulsifying capability of SSP.The emulsifying activity index (EAI) of SSP had the maximum value (45.78m2/g) on the condition of pH 7.94, ironic strength 0.7, the ratio of oil to water volume 1:7.pH was the significant factor which influenced emulsifying stability of SSP.The emulsifying stability index (ESI) of SSP had maximum value on the condition of pH 7.3, ironic strength 0.58, the ratio of oil to water volume 1:5.The optimal condition of emulsifying properties of SSP from grass carp were pH 7.5, ironic strength 0.6, the ratio of oil to water volume 1:7.