本文研究了乌鳢短肽螯合铁的制备工艺及其结构特性。利用胰蛋白酶水解乌鳢蛋白，通过单因素和响应面实验优化制备得到螯合率较高的乌鳢短肽螯合铁，并通过氨基酸分析、光谱扫描、电镜扫描对其结构进行了解析。在加酶量35000 U/g，pH 6.0、短肽与氯化亚铁质量比3:1、螯合温度25 ℃、螯合时间30 min的条件下得到螯合率为84.46%的乌鳢短肽螯合铁。螯合前后氨基酸分析显示螯合后短肽中天冬氨酸和谷氨酸的含量显著增加，说明酸性氨基酸对亚铁离子有较强的螯合作用。乌鳢螯合铁形成前后紫外、红外吸收光谱发生明显偏振，肽-铁之间的螯合连接形成，表明短肽的氨基和羧基参与螯合反应。通过电子显微镜表征乌鳢短肽螯合前后的微观结构差异，表征了螯合铁的特征结构与形成规律，说明短肽与亚铁离子之间存在吸附作用，结构紧密。研究结果将为乌鳢的高值化利用提供一些理论依据。

In this study, the preparation process and structural characteristics of the short peptides chelated ferrous ions from channa argus were investigated. The short peptides were obtained from channa argus protein by trypsin hydrolysis. Single factor and response surface analyses were applied to optimize the preparation of higher chelating rate short peptides chelated ferrous ions from channa argus. Its structure was analyzed by means of amino acid analysis, spectral scanning and electron microscopy. The optimal chelating conditions were listed as follow: enzyme dosage of 35000 U/g, pH of 6.0, peptides/iron chloride of 3:1 (m/m), chelating temperature of 25 ℃, chelating time of 30 mins. The value of the highest chelating rate was 84.46 % at this condition. The amino composition analysis of the short peptides showed that the content of aspartic acid and glutamic acid had significantly increased after chelating reaction, suggesting that acid amino acid had stronger chelating effect on ferrous ions. Ultraviolet-visible (UV-VIS) spectrum, fourier transform-infrared (FT-IR) spectra were obviously polarized and the chelating connection of peptide-iron was formed before and after chelating reaction, suggesting that the amino and carboxyl of the short-peptide were involved in chelating reaction. The microstructure of the short peptides chelated ferrous ions was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), suggesting that there was an adsorption effect between the short peptide and the ferrous ion, and the structure was close. This study provides some theoretical basis for the high value utilization of the channa argus.

国家863子课题（2013AA102201-3）；广东省科技项目（2016A050502031、2017A040405038、2016A040403080）；广州市科技项目（2016201604030060、201704020081）；广东农业需求项目（2016LM2151、2016LM3167）