鱿鱼墨黑色素酶解法提取工艺优化及其紫外、红外光谱特征分析

Optimization of Enzymatic Preparation of Natural Melanin from Squid Ink and Its Spectral Characterization

以鱿鱼墨水解度为指标,分别测定木瓜蛋白酶、中性蛋白酶、酸性蛋白酶、胃蛋白酶和胰蛋白酶对鱿鱼墨水解效果,选用水解能力最强的胃蛋白酶为试验用酶,测定酶解反应pH值、反应时间、反应温度和加酶量对鱿鱼墨水解度的影响。在单因素试验基础上进行L9(34)正交试验优化得到胃蛋白酶水解鱿鱼墨的最佳酶解条件为酶解反应pH1.5、酶解温度37℃、酶解反应时间5h、加酶量1.5%。在最优酶解反应条件下,胃蛋白酶水解鱿鱼墨的水解度大于13.50%。紫外-可见光谱分析显示酶解法制备的鱿鱼墨黑色素在220nm处有特征吸收波长,红外光谱中的3384.54cm-1和1617.35cm-1处出现吲哚环结构归属的强吸收峰。

In this work,the enzymatic hydrolysis of squid ink was investigated to prepare natural melanin.Squid ink was hydrolyzed by papain,neutral protease,acidic protease,pepsin and tyrpsin,respectively,and pepsin was found to have the strongest ability to hydrolyze squid ink.Based on one-factor-at-a-time experiments,an L9（34） orthogonal array design was used to optimize the hydrolysis of squid ink by pepsin.The degree of hydrolysis of squid ink was investigated with respect to pH,hydrolysis time,temperature and enzyme amount.The four conditions were optimized as follows： pH 1.5,temperature 37 ℃,reaction time 5 h and pepsin amount 1.5%.Under the optimized conditions,the degree of hydrolysis of squid ink exceeded 13.50%.Ultraviolet-visible spectral analysis revealed the characteristic absorption of melanin derived from squid ink at 220 nm wavelength.High-intensity absorption peaks at 3384.54 cm-1 and 1617.35 cm-1,assigned to the structure of indole ring were observed in the infrared spectrum.