琥珀酰化处理对芸豆蛋白乳化性和体外消化性的影响

Effects of Succinylation on Emulsifying Properties and in vitro Trypsin Digestibility of Red Kidney Bean (Phaseolus vulgaris L.) Protein Isolate

本文研究了琥珀酰化对芸豆分离蛋白（KPI）乳化性和体外消化性的影响。KPI酰化包括两个主要的阶段，酸酐-蛋白比为0-0.2．2，为ε-氨基（Lys）酰化阶段（N-酰化）；再增加酸酐与蛋白比，ε-氨基酰化基本完成，反应进入羟基（Thr,Ser）酰化阶段（O-酰化）。在低离子强度下，蛋白的EAI和ESI随N-酰化度增加急剧增加，而O-酰化基本不影响蛋白的EAI和ESI；对照和酰化KPI的EAI和ESI均随溶剂体系离子强度增加而降低。酰化改善KPI的体外消化性能。

The effects of suecinylation on emulsifying property and the in vitro trypsin digestibility of kidney bean protein isolate （KPI） were investigated. The succinylation of KPI included two stages： one is the succinylation of ε-amino groups （N- succinylation） and the other is the succinylation of hydroxyl groups （O-succinylation）. The degree of the N-suecinylation sharply increased to about 93-94% with the anhydride levels increasing from 0 to 0.2. The O-acylation （Thr, Set） distinctly occurred only when the N-acylation was nearly complete. The O-acylation occurred only after extensive blocks of ε-amino groups. At low ionized strength, the EAI and EAS increased as the degree of N-succinylation, while the EAI and EAS of succinylated KPI were nearly unaffected in N-succinylation. The EAI and ESI of untreated or succinylated KPI decreased as the ionized strength of the tested solution increased. Additionally, the in vitro trypsin digestibility was improved by the succinylafion in a dose-dependent manner. The present data indicated that the succinylation could be used to modulate the emulsifying and in vitro digestibility of kidney bean protein isolate （KPI）.