响应面法优化罗非鱼鳞钙结合肽酶解工艺及其特性表征

为研究罗非鱼鳞钙结合肽酶解制备最佳工艺条件及其螯合特性，从而为促钙吸收活性物质的研究提供基础，本研究以脱钙罗非鱼鳞为原料，钙螯合活性为指标，选用木瓜蛋白酶对罗非鱼鳞酶解工艺进行优化，获得罗非鱼鳞钙结合肽，并通过氨基酸分析、紫外光谱和红外光谱表征肽钙螯合特性。结果表明，罗非鱼鳞钙结合肽的最优酶解条件为底物浓度8%、时间2 h、酶底比0.3%、pH7、温度60 ℃，在此条件下酶解物钙螯合活性为(38.31±0.4) μg/mL。表征结果表明，螯合钙离子后，肽钙螯合物中天冬氨酸、谷氨酸、甘氨酸、赖氨酸、丝氨酸、半胱氨酸及组氨酸的含量分别增加了0.88%、1.48%、0.34%、0.53%、0.04%、0.38%、0.46%。钙结合肽中的羧基氧和氨基氮等基团参与了与钙离子的结合，形成了罗非鱼鳞肽钙螯合物。罗非鱼鳞钙结合肽具有较高的钙螯合活性，这为补钙剂的生产应用奠定了基础。

Optimization of Enzymatic Hydrolysis of Tilapia Scale Calcium Binding Peptides by Response Surface Methodology and Its Structural Characterization

In order to obtain the optimum enzyme hydrolysis conditions and chelating properties of tilapia scale calcium binding peptides, and provide basis for study of promoting calcium absorption of active material, in this study, the decalcified tilapia scales as raw material and calcium chelation activity as an index, papain was selected to optimize enzyme hydrolysis of the tilapia scales to obtain tilapia scale calcium binding peptides. The properties of the tilapia scale calcium binding peptides were characterized by amino acid analysis, ultraviolet-visible spectroscopy and fourier transform infrared spectroscopy. The optimal enzymatic hydrolysis conditions were as follows: the concentration of substrate 8%, time 2 h, enzyme to substrate ratio 0.3%, pH7 and temperature 60 ℃. Under these conditions, the calcium chelation activity of the enzymatic hydrolysate was (38.31±0.4) μg/mL. The results of characterization showed that, after chelating calcium, the contents of aspartic acid, glutamic acid, glycine, lysine, serine, cysteine and histidine in peptide-calcium chelate increased by 0.88%, 1.48%, 0.34%, 0.53%, 0.04%, 0.38% and 0.46%, respectively. The carboxyl oxygen and amino nitrogen groups in the calcium binding peptides participated in binding with calcium ions to form the tilapia scale peptide-calcium chelate. Tilapia scale calcium binding peptides has high calcium chelation activity, which lays a foundation for the production and application of calcium supplements.