超声辅助提取鲵皮胶原蛋白工艺优化及结构特征分析

Optimization of Ultrasound-assisted Extraction and Structural Characteristics Analysis of Collagen from Chinese Giant Salamander(Andrias davidianus)Skin

人工养殖大鲵皮中含有大量的胶原蛋白,常规提取方法从鲵皮中获得胶原蛋白提取率较低,为提高鲵皮胶原蛋白提取率,本研究采用超声辅助技术处理鲵皮,应用Box-Behnken设计对超声辅助酶法提取鲵皮中的胶原蛋白工艺进行优化,考察超声功率、超声时间和液固比三个自变量对胶原蛋白提取率的影响;并通过扫描电镜、十二烷基硫酸钠聚丙烯酰胺凝胶电泳、傅里叶变换红外和氨基酸分析等技术对鲵皮胶原蛋白进行结构特征分析。结果表明,超声辅助提取最佳工艺条件为:超声功率201 W,超声时间26 min,液固比21:1 mL/g,在此条件下,鲵皮胶原蛋白的提取率为37.36%±2.61%(n=3),接近模型的预测值(37.76%),明显高于未用超声处理鲵皮胶原蛋白的提取率(17.56%±1.77%)。超声辅助处理增大了鲵皮表面结构的孔隙度,有助于胶原蛋白溶出;从鲵皮中提取的胶原蛋白为I型;超声处理使鲵皮胶原蛋白的二级结构单元α-螺旋和β-转角含量降低,β-折叠、无规则卷曲和β-反平行折叠含量升高,微观结构更加密集,氨基酸组成则无明显变化。本研究为鲵皮胶原蛋白工业化生产提供了一种有效方法,为人工养殖大鲵资源的后续开发利用提供参考。

Artificial-breeding salamander skin contains a lot of collagen.The yield of collagen extracted from the skin of salamander by conventional extraction method was low.In order to improve the collagen yield from the skin of salamander,the ultrasonic-assisted technology was used to treat the skin of salamander.The Box-Behnken design was used to optimize the process of ultrasonic-assisted enzymatic extraction of collagen from the skin of salamander.The effects of ultrasonic power,ultrasonic time and liquid-solid ratio on the collagen yield were investigated.Scanning electron microscopy(SEM),sodium dodecyl sulfate polyacrylamide gel electrophoresis,Fourier transform infrared(FT-IR)and amino acid analysis were used to characterize the collagen of salamander skin.The results showed that the optimal conditions of ultrasonic assisted extraction were as follows:ultrasonic power 201 W,ultrasonic time 26 min,liquid-solid ratio 21:1 mL/g.Under these conditions,the collagen yield of salamander skin was 37.36%±2.61(n=3),close to the predicted value of the model(37.76%),significantly higher than that of salamander skin collagen without ultrasonic treatment(17.56%±1.77%).Ultrasound assisted treatment increased the surface porosity of salamander skin,which was helpful for collagen dissolution.Collagen extracted from the skin of salamander was type I.Ultrasound treatment reduced the content ofα-helix andβ-turning angles,increased the content ofβ-folding,irregular coiling andβ-anti-parallel folding in the secondary structural units of salamander skin collagen,and made the microstructure more dense,while the amino acid composition did not change significantly.This study would provide an effective method for industrial production of skin collagen of salamander,and would provide a reference for the subsequent development and utilization of artificial-breeding salamander resources.