To optimize the ethanol extraction conditions of floridoside and to investigate the effect of floridoside on the myofibrillar protein freezing denaturation of grass crap surimi during frozen storage. Ethanol concentration,extraction temperature, extraction duration and liquor to material ratio were optimized by response surface methods. The salt-solubility of myofibrillar protein, sulfhydryl content, and Ca2+-ATPase activity, etc in surimi after being frozen for 6 weeks were detected. Results showed that th...