海蜇伞部酶促溶性胶原蛋白的热变性动力学

为阐明海蜇伞部酶促溶性胶原蛋白(pepsin-solubilized collagen,PSC)的热变性反应机理,以保持完整三螺旋结构的PSC为研究对象,通过微量热仪测定不同升温速率条件下PSC的变性温度,以及采用34、35、36、37、38、39℃加热不同时间后的PSC残存率,并进行热变性动力学分析。结果表明,海蜇伞部PSC对热变化敏感,随着加热温度升高,单位时间内提高的热量增加,使海蜇伞部PSC变性速率加快,完成变性时间缩短;随着升温速率的减慢,吸热峰逐渐向低温区移动,即变性温度随升温速率的减慢而降低,但升温速率的变化对反应热并无显著影响。反应级数为0.9的回归方程能够较好地描述PSC热变性过程,在恒温34、35、36、37、38℃及39℃的条件下,PSC变性的D90值(90%蛋白变性所需时间)分别为53.76、26.11、15.75、4.89、4.26、2.55 min,Z90值(D值降低90%的温度变化)为3.69℃,表观活化能为481.90 k J/mol。研究结果可为海蜇胶原蛋白的进一步开发利用提供理论参考。

Thermal Denaturation of Pepsin-Solubilized Collagen from Rhopilema esculentum Umbrella

In order to elucidate the thermal denaturation mechanism of pepsin-solubilized collagen (PSC), intact PSC was extracted from jellyfish umbrella. The denaturation temperature of PSC under different heating rates, and the rates of residual PSC after heating at different temperatures for different times were investigated by a microcalorimeter. The thermal denaturation kinetics of PSC was analyzed as well. The results showed that the endothermic peak gradually moved towards lower temperature area with the decrease in heating rate, suggesting that the denaturation temperature of PSC declined with the decrease in heating rate. However, the change in heating rate did not show any significant impact on the heat of reaction. As the temperature rose, the increase of energy per unit time, namely the quantity of heat, could increase the degeneration rate of PSC, thereby shortening the degeneration time of PSC. The thermal denaturation process of PSC could be described by a regression equation with a reaction order of 0.9. At 34, 35, 36, 37, 38 and 39 ℃, the D90 values (time required for 90% denaturation) were 53.76, 26.11, 15.75, 4.89, 4.26 and 2.55 min, respectively. The Z90 value (temperature change for 90% reduction of D value) was 3.69 ℃. The apparent activation energy was 481.90 kJ/mol. This research can provide a theoretical guideline for further development and utilization of jellyfish collagen.