椰子蛋白化学结构和热稳定性研究

Chemical structure and thermal stability of Cocos nucifera L. protein

中文关键词:  关键词：椰子蛋白  氨基酸  二级结构  热重分析  粒径

英文关键词:Cocos nucifera L. protein  amino acids  secondary structure  thermogravimetric analysis  particle size

中文摘要:

      目的 研究椰子全粉中蛋白质的结构和热稳定性, 为深度开发椰子蛋白资源提供理论基础。方法 采用碱提酸沉法提取椰子全粉中蛋白质, 酸水解法结合氨基酸自动分析仪测定氨基酸组成, 利用傅里叶变换红外光谱法分析蛋白二级结构, 热重分析仪分析蛋白热降解曲线, 纳米粒度分析仪研究溶液中蛋白颗粒的Zeta电位和粒径大小。结果 椰子蛋白含有18种氨基酸, 富含精氨酸和谷氨酸, 8种必需氨基酸含量丰富、比例合理, 是营养良好的蛋白质来源。椰子蛋白的二级结构以稳定态的β-折叠为主, 含量达44.18%, 椰子蛋白降解起始温度273.12℃, 峰值温度332.91℃, 至最终实验设定温度790℃时仍有25.9%残余未热降解完全, 60℃时椰子蛋白溶液Zeta电位和粒径与25℃无显著变化。结论 椰子蛋白具有良好的营养价值和热稳定性, 可为椰子蛋白资源的深度开发和广泛利用提供理论参考。

英文摘要:

      Objective To study the the structure and thermal stability of Cocos nucifera L. protein, and provide theoretical basis for further development of Cocos nucifera L. protein resources. Methods The alkali extraction and acid precipitation method was used to extract the protein from Cocos nucifera L. powder. The amino acid composition of Cocos nucifera L. protein was determined using acid hydrolysis method combined with an automatic amino acid analyzer. The secondary structure of Cocos nucifera L. protein was analyzed using Fourier transform infrared spectroscopy. The thermal degradation curve of Cocos nucifera L. protein was analyzed using a thermogravimetric analyzer. The Zeta potential and particle size of the Cocos nucifera L. protein particles in the solution were studied using a nanoparticle size analyzer. Results Cocos nucifera L. protein contained 18 kinds of amino acids with a reasonable proportion and high content of essential amino acids, rich in arginine and glutamic acid, making it a good nutritious source of protein. Stable β-folding with a content of 44.18%, was the main secondary structure of Cocos nucifera L. protein. The initial temperature of Cocos nucifera L. protein degradation was 273.12℃, and the peak temperature was 332.91℃. At the final temperature of 790℃, there was 25.9% of the residue was not completely thermally degraded. The Zeta potential and particle size of Cocos nucifera L. protein solution showed no significant changes at 60℃ compared to 25℃. Conclusion Cocos nucifera L. protein has good nutritional value and good thermal stability, which can provide theoretical reference for the deep development and wide utilization of Cocos nucifera L. protein resources.