Abstract: Fish surimi is usually rinsed 2 to 3 times during processing to increase the whiteness and elasticity, and to remove fishy smell. At the same time, the water-soluble proteins are lost with rinsing water. Thus the present researches were aimed to recover the sarcoplasmic protein from rinsing water. The thermal characteristics of the recovered protein were valuable for further study of the protein recycling. Rinsing water of catfish surimi were recovered by centrifugation, and the supernatant contained catfish sarcoplasmic protein （CSP）. Influence of different temperatures on turbidity, total sulfydryl content, surface hydrophobicity, aggregation and degeneration of CSP were studied. The results show that the above properties of CSP were significantly influenced by heating temperature. The results of SDS-PAGE revealed that CSP degenerated and polymerized significantly during heating. CSP turbidity significantly increased and the total sulfydryl content decreased when the heating temperature reached 55 ℃. The surface hydrophobicity raised then declined with increased heating temperature. The results proved that CSP denatured at 55 ℃. It is proposed that 55 ℃ was the key point of CSP denaturation.

Key words: catfish, sarcoplasmic protein, rinsing water, heating temperature