琥珀酰化改性对鹰嘴豆分离蛋白结构和功能特性的影响

Effect of succinylation modification on structure and functional properties of chickpea protein isolate

鹰嘴豆蛋白具有氨基酸比例均衡、低致敏性等优点,但溶解度低、功能特性无法满足现代食品工业的需求。通过添加琥珀酸酐对鹰嘴豆分离蛋白(chickpea protein isolate,CPI)进行酰化改性处理,研究不同琥珀酸酐添加量(0~0.3 g/g pro)对CPI理化结构和功能特性的影响。结果表明,CPI酰化度随琥珀酸酐添加量的增加而升高,琥珀酸酐添加量达到0.2 g/g pro后酰化度基本达到平衡(92.48%)。红外光谱结果证实了CPI琥珀酰化改性的发生,带负电荷的琥珀酰基基团结合在CPI表面,此时改性CPI的电负性升高,平均粒径减小。改性后蛋白表面疏水性降低,分子柔性提高,蛋白分子结构由有序变得无序,电荷密度的增加使内部基团暴露,三级结构伸展,形成疏松的片层结构。当琥珀酸酐添加量为0.2 g/g pro时,CPI的功能性质改善效果最佳,溶解度达到86.52%,乳化活性为61.696 m^(2)/g,持水性和持油性分别提高了3.79、1.73倍。当前研究证实琥珀酰化有利于改善CPI的结构和功能性质,对鹰嘴豆加工及其CPI产品的品质提升具有重要意义。

Chickpea protein has the advantages of a balanced amino acid ratio and low allergenicity,but its low solubility and functional characteristics cannot meet the needs of the modern food industry.Chickpea protein isolate(CPI)was acylated by using succinic anhydride,and the effects of different succinic anhydride additions(0-0.3 g/g pro)on the physicochemical structure and functional properties of CPI were investigated.Results showed that the acylation degree of CPI increased with the addition of succinic anhydride,and the acylation degree basically reached equilibrium after the addition of succinic anhydride reached 0.2 g/g pro(92.48%).The Fourier Transform infrared spectroscopy results confirmed the occurrence of CPI succinylation,and the negatively charged succinyl group was bound to the surface of CPI,thus the electronegativity of the modified CPI increased and the average particle size decreased.After modification,the surface hydrophobicity of the protein decreased,the molecular flexibility increased,the protein molecular structure changed from an ordered structure to a disorder,the increase of charge density resulted in the exposure of the internal groups and the tertiary structure was stretched to form a loose lamellar structure.When the amount of succinic anhydride was 0.2 g/g pro,the functional nature of CPI had the best improvement effect,in which the solubility was 86.52%,the emulsifying activity was 61.696 m 2/g,and the water holding capacity and oil holding capacity increased by 3.79 times and 1.73 times,respectively.The current study confirms that succinylation can improve the structure and functional properties of CPI,which is of great significance for chickpea processing and the quality improvement of CPI products.