温度对乌鳢鱼皮胶原蛋白肽聚集体结构及理化特性的影响

研究乌鳢鱼皮胶原蛋白肽在20～52 ℃低温诱导下自组装体的结构稳定性与理化性质，比较分析聚集体变化过程中圆二色谱、自组装动力学、微观结构、凝胶强度、粒径、黏度、变性温度和红外光谱的变化。结果表明：在20～30 ℃温度范围内，升温对乌鳢鱼皮胶原蛋白肽自组装速率及聚集体稳定性具有促进作用，组装成核时间缩短13.5 min，形成的三维网络致密性增强，平均粒径增大，凝胶强度从50.23 g/cm2升高至212.55 g/cm2（P＜0.05），最大剪切黏度增加549.34%，β-折叠相对含量增加45.42%，胶原蛋白肽结构稳定性显著增强；在30～52 ℃温度范围内，升温促使纤维网络结构发生溶解和絮集，凝胶强度降低97.87%（P＜0.05），粒径降低46.16%，最大剪切黏度和β-折叠相对含量降低；差示量热扫描测定结果表明，聚集体自组装程度越高，其热稳定性越强。因此，适宜的温度可有效改善乌鳢鱼皮胶原蛋白肽纤维网络的结构稳定性及理化性质。

Effect of Temperature on Aggregation Structure and Physicochemical Properties of Collagen Peptide from Snakehead Fish (Channa argus) Skin

This study was designed in order to investigate the structure and physicochemical properties of self-assembled collagen peptide (CP) from snakehead fish skin induced by low temperatures 20–52 ℃ and to compare changes in circular dichroism (CD) spectra, self-assembly kinetics, microstructure, gel strength, particle size, viscosity, denaturation temperature and infrared spectra during the aggregation process. The results indicated that the increase of temperature in the range of 20–30 ℃ could promote the self-assembly rate and aggregate stability of CP, reduce the assembly nucleation time by 13.5 min, lead to the formation of a more compact three-dimensional network, increase the average aggregate size, raise the gel strength significantly from 50.23 to 212.55 g/cm2 (P < 0.05), increase the maximum shear viscosity by 549.34% and β-sheet content by 45.42%, and significantly enhance the structural stability of CP. However, the increase of temperature in the range of 30–52 ℃ could facilitate the dissolution and flocculation of the fibrous network structure, decrease the gel strength by 97.87% (P < 0.05) and the average particle size of aggregates by 46.16% (P < 0.05), and reduce the maximum shear viscosity and β-sheet content. Differential scanning calorimetric (DSC) results showed that the higher the degree of self-assembly, the stronger the thermal stability. In conclusion, the fibrous network structure stability and physicochemical properties of CP could be effectively improved at a suitable temperature.