关键词: 草鱼鱼鳞, 多肽, 清除自由基作用, 响应面

Abstract:

Complex proteases were used to hydrolyze grass carp scales for preparing polypeptides with high hydroxyl free radical scavenging activity in the present study. To maximize hydroxyl free radical scavenging activity of polypeptides prepared from grass carp scales, three crucial hydrolysis parameters were investigated by response surface analysis based on central composite design. Besides, hydrolysis products of grass carp scales obtained were purified/fractionated by Sephadex G-15 column chromatography and the resulting fractions were evaluated for hydroxyl free radical activity. The optimal values of the above parameters for improved hydrolysis of grass carp scales were determined as follows: substrate concentration 6 g/100 mL, enzyme dose 5.22 g/ 100 mL and reaction temperature 49.33 ℃ for a hydrolysis duration of 2.11 h. Under the optimized parameters, a maximum hydroxyl free radical scavenging activity of hydrolyzed grass carp scales of 99.24% was obtained. Sephadex G-15 column chromatographic separation resulted in 5 fractions and the highest scavenging rate (98.34%) against hydroxyl free radicals was observed in the fourth fraction.

Key words: carp scale, polypeptide, hydroxyl free radical scavenging activity, response surface analysis