草鱼和乌鳢鱼皮胶原体外自组装过程中的凝胶化行为比较研究

以草鱼和乌鳢鱼皮胶原为研究对象，分别采用浊度实验和流变学实验方法研究两种胶原的体外自组装行为和凝胶化行为。结果表明：两种胶原的组装浊度曲线和流变黏弹曲线均表现为典型的3 阶段模式，即成核段、组装段和平衡段。浊度实验测定的胶原组装成核时间为13.5 min（草鱼PSC）和3.5 min（乌鳢PSC），平衡时间为72.6 min（草鱼PSC）和10.0 min（乌鳢PSC）；而流变学实验测定的胶原组装成核时间为6.7 min（草鱼PSC）和1.9 min（乌鳢PSC），平衡时间为105 min（草鱼PSC）和58.0 min（乌鳢PSC）。流变学实验测定的成核段时间明显缩短而组装段时间显著延长。扫描电镜纤维直径分析结果表明：胶原纤维直径在浊度实验平衡时间之后仍在继续增长直至流变学测定的平衡时间，说明流变黏弹实验能更灵敏、更完整地反映胶原的体外自组装行为。与草鱼皮胶原相比，乌鳢胶原组装速率更快、形成的胶原凝胶强度更大，说明不同种类胶原体外自组装行为存在明显的差异性。

Comparison of Gelling Behavior of Skin Collagen from Grass Carp and Snakehead during Self-Assembling in vitro

In this study, the self-assembling behavior of collagen from grass carp and snakehead skin was investigated by
applying turbidity and rheology methods. The results indicated that both turbidity curve and rheology curve of the two
collagens showed a three-stage pattern including nucleation phase, assembling phase and equilibrium phase. In turbidity
tests, the time of nucleation phase was 13.5 and 3.5 min, and the time of assembling phase was 72.6 and 10.0 min for pepsinsolubilized
collagen (PSC) from grass carp and snakehead skins, respectively. In rheology tests, the time of nucleation
phase were 6.7 and 1.9 min, and the time of assembling phase was 105 and 58 min for skin PSC from grass carp and
snakehead, respectively. Compared with the results of turbidity tests, the time of nucleation phase was shorter and the time
of assembling phase was longer according to the results of rheology tests. The collagen fiber diameter was further increased
after the equilibrium phase from turbidity tests until the equilibrium phase from rheology tests was reached, and then
remained stable, suggesting that the self-assembling behavior of collagen could be more sensitively and integrally observed
by rheology method when compared with turbidity tests. Based on the results of rheology tests, the assembling rate of
snakehead collagen was faster and the assembling collagen gel was harder than that of grass carp collagen, indicating that
self-assembling behavior among different collagens is different.