氢氧化钠预处理对罗非鱼皮胶原蛋白自组装性的影响

Effect of Pretreatment with Sodium Hydroxide on Self-Assembly Properties of Collagen from Tilapia Skin

摘要: 罗非鱼皮存在大量色素，严重影响了胶原蛋白的品质，NaOH溶液预处理可有效去除杂质，同时会影响胶原的自组装性。因此，本研究分别以0.5、1.0和1.5 mol/L NaOH溶液对罗非鱼皮进行预处理，采用胃蛋白酶法提取酶促溶性胶原，测定其得率及纯度；通过衰减全反射傅里叶变换红外光谱、ANS荧光探针表征PSC结构与疏水性，监测400 nm吸光度分析自组装动力学并计算自组装比率；借助扫描电子显微镜表征PSC自组装体的微观结构。结果表明，碱液预处理能够有效去除鱼皮中的色素并提升PSC的纯度，但得率下降，1.0 mol/L NaOH处理至脱色时，PSC的得率、疏水性及自组装性最优；预处理时间延长会延缓PSC自组装，使PSC自组装体的纤维更细、网络更致密。本研究结果表明，1.0 mol/L NaOH预处理的罗非鱼皮胶原蛋白在食品和生物材料领域具有广阔的应用前景。

Abstract: The abundant pigments present in tilapia skin severely affect the quality of collagen. Pigments can be effectively removed by NaOH solution pretreatment, though the self-assembly property of collagen is simultaneously affected. Therefore, tilapia skin was pretreated with 0.5, 1.0, and 1.5 mol/L NaOH solutions, respectively. Pepsin-solubilized collagen (PSC) was extracted by pepsin hydrolysis and purified by salting-out, and its yield and purity were determined. The structure and hydrophobicity of PSC were characterized by attenuated total reflection Fourier transform infrared spectroscopy and ANS fluorescent probe. The self-assembly kinetics was analyzed by monitoring absorbance at 400 nm, and the self-assembly ratio was calculated. The microstructure of PSC self-assemblies was observed by scanning electron microscopy. The results showed that pigments were effectively removed from fish skin by alkaline pretreatment, and the purity of PSC was increased, although the yield was decreased. When skin was pretreated with 1.0 mol/L NaOH until decolorization, the yield, hydrophobicity, and self-assembly performance of PSC were optimal. Prolonged pretreatment time delayed PSC self-assembly, resulting in finer fibers and a denser network. These findings indicate that tilapia skin collagen pretreated with 1.0 mol/L NaOH holds broad application prospects in the food and biomaterial fields.