响应面法优化微波辅助酶解合浦珠母贝蛋白工艺

研究微波对酶解合浦珠母贝蛋白的影响,以水游离氨态氮含量和抗氧化活性为指标,选择较好的作用酶,通过单因素试验确定料液比、加酶量(E/S)、微波温度、微波功率及时间和后续水浴时间等因素水平,以水解度和DPPH自由基清除率为响应值,响应面法优化酶解合浦珠母贝蛋白工艺条件。结果表明,微波辅助蛋白酶酶解合浦珠母贝蛋白工艺条件为微波温度58℃、微波功率300 W、微波时间17 min、加酶量5 000 U/g,后续在58℃条件下再水浴1.5 h。预测响应值为0.224 4,水解度达到26.15%,验证实验证明与响应优化模型预测值误差不大,二次多元拟合度较好。

三种物理法辅助蛋白酶水解合浦珠母贝蛋白的效果评价

目的:研究了微波法(W)、超声法(U)与传统水浴法(H)3种模式辅助7种常用酶(Alcalase 2.4L蛋白酶、菠萝蛋白酶、木瓜蛋白酶、胰蛋白酶、风味蛋白酶、胃蛋白酶和枯草蛋白酶)酶解合浦珠母贝蛋白的效果。方法:通过RPHPLC法与Tricine-SDS-PAGE电泳实验,结合水解度、DPPH·清除率、·OH自由基清除率等评价指标。结果:物理辅助酶解能有效促进水解,微波结合木瓜蛋白酶、胰蛋白酶和枯草蛋白酶处理,其作用效果优于超声波法和传统水浴法;Alcalase 2.4L蛋白酶与复合风味蛋白酶在三种辅助模式下相似。结论:综合各指标结果得出,微波助解合浦珠母贝蛋白最佳的酶为Alcalase 2.4L蛋白酶与复合风味蛋白酶。

Effect of Temperature on Gene Expression in the Pearl Oyster Pinctada fucata

In this study, we examined the effect of elevated temperature on the expression patterns of genes, i.e., nacrein, irr, n16, n19, and hsp70 in the pearl oyster Pinctada fucata. The experiment was carried out at 4 temperatures, i.e., 20℃(ambient, control), 24, 28℃, and 32℃. The expression levels of target genes in P. fucata were assayed at 0, 6, 24, 48, and 96 h via real-time polymerase chain reaction. Results showed that the expression levels of nacrein and irr had no significant variations among different time points below 28℃, but significantly increased over time at 32℃. The expression levels of n16 and n19 did not change markedly at 20℃. The former increased significantly at 6 h and 24 h while the latter substantially decreased during 6–96 h at 24, 28 and 32℃. Among different temperatures, the level of n16 was significantly lower at 20℃ than at other temperatures during 6–96 h, and the level of n19 significantly varied among different temperatures at 48 h and 96 h. The expression level of hsp70 was significantly higher at 32℃ than at 20, 24 and 28℃ at 24 h. These results demonstrated that elevated temperature impacted the physiological processes of P. fucata and potentially influenced its adaptability to thermal stress.