γ-聚谷氨酸对罗非鱼皮酶促溶性胶原自聚集性的影响

Effects of γ-Polyglutamic Acid on the Self-Assembly of Pepsin-Solubilized Collagen from Tilapia(Oreochromis niloticus) Skin

研究γ-聚谷氨酸对罗非鱼皮酶促溶性胶原自聚集动力学和自聚集水凝胶的微观结构及性能的影响。结果表明,在不同含量γ-聚谷氨酸存在的条件下,胶原自聚集过程仍然包含成核阶段和生长阶段,但是γ-聚谷氨酸能够延长胶原的成核时间,并降低成核阶段的速率常数,而生长阶段的速率常数先增加后降低。胶原自聚集能够形成外观为白色的水凝胶,经扫描电镜观察其为三维纤维网络结构,但是γ-聚谷氨酸能够影响到胶原纤维的致密度,当γ-聚谷氨酸相对胶原的百分比增加到80%时,网络致密度表现增加趋势,当其进一步增加到100%时,致密度显著下降,相对应的凝胶强度也先增强后减弱。然而,γ-聚谷氨酸并未显著提高水凝胶的耐酶性和热稳定性,因此下一步研究将引入交联等技术进一步改善水凝胶的性能。

The effects of γ-polyglutamic acid(γ-PGA) on the kinetic self-assembly of pepsin-solubilized collagen(PSC)from tilapia(Oreochromis niloticus) skin and the microstructure and properties of the resulting hydrogel were investigated.It was found that the self-assembly process of PSC consistently involved the nucleation and growth phases in the presence of various concentrations of γ-PGA, but it prolonged the nucleation time, and decreased the rate constant of the nucleation phase, whereas it firstly rose and then reduced that of the growth phase. After the self-assembly, PSC was formed into a white hydrogel, which showed a three-dimensional fibril network as observed by scanning electron microscopy, but γ-PGA could affect the density of collagen fibrils. The network density displayed an increasing trend with increasing γ-PGA/PSC ratio up to 80%, but significantly decreased as the ratio further increased to 100%. Correspondingly, the gel strength was firstly enhanced and then weakened. Nevertheless, neither the enzymatic resistance nor thermal stability of the collagen hydrogel was improved evidently by γ-PGA, suggesting that further studies are necessary to enhance the gel properties by cross-linking.