脆性形成过程中脆肉鲩肌肉肌浆蛋白结构变化

以脆性形成过程中鱼肉肌浆蛋白为原料，通过分析肌浆蛋白总巯基、表面疏水性、荧光光谱和红外光谱等结构信息变化，探讨脆肉鲩脆性形成过程中肌肉肌浆蛋白结构变化规律。结果表明：在脆性的形成过程中，肌浆蛋白总巯基含量呈下降趋势，脆性形成末期下降了35.02%（P＜0.05）；表面疏水性呈上升趋势，脆性形成末期上升了65.83%（P＜0.05）；荧光峰位置发生蓝移，脆性形成末期蓝移了5.24%（P＜0.05）。红外光谱显示脆肉鲩脆性形成过程中肌肉肌浆蛋白均有红外光谱的特征吸收峰：酰胺A、B、Ⅰ、Ⅱ、Ⅲ，各吸收峰位置有波动。肌浆蛋白二级结构显示，脆肉鲩脆性的形成伴随着肌浆蛋白α-螺旋的减少，β-折叠、β-转角和无规则卷曲的增加。在脆肉鲩脆性形成过程中，肌肉肌浆蛋白结构的逐渐变化是脆肉鲩脆性形成的影响因素。

Structural Changes of Muscle Sarcoplasmic Protein from Crisp Grass Carp (Ctenopharyngodon idellus C. et V) during Crispness Formation

The structural changes of muscle sarcoplasmic protein from crisp grass carp during crispness formation were investigated by measuring total sulfhydryl content, surface hydrophobicity, fluorescence spectrum and infrared spectrum. The results indicated that total sulfhydryl content was decreased along with crispness formation, showing a decrease of 35.02% at the end of the process (P < 0.05). Surface hydrophobicity showed an increase of 65.83% until the end of crispness formation (P < 0.05). The peak position in the fluorescence spectrum was significantly blue-shifted by 5.24% at the end of crispness formation (P < 0.05). Furthermore, infrared spectroscopy showed that characteristic absorption peaks (amides A, B, Ⅰ, Ⅱ and Ⅲ) were observed for muscle sarcoplasmic protein during crisp formation, the position of each of which was fluctuated. The secondary structure of sarcoplasmic protein showed that the relative contents of α-helix were decreased whereas those of β-sheet, β-turn and random coil were increased along with crispness formation. The structure of muscle sarcoplasmic protein changed gradually during crispness formation in grass carp, thereby affecting crispness formation.