小麦α-醇溶蛋白体外克隆表达及脱酰胺改性对面条机械特性的影响  

In Vitro Expression of Cloned α-Gliadin and Effect of Deamidated α-Gliadin on the Mechanic Properties of Noodles

作　　者：廖兰 张风丽 李章发 陈林萍 林维杰 杨彦红 文晓艳 倪莉 LIAO Lan;ZHANG Fengli;LI Zhangfa;CHEN Linping;LIN Weijie;YANG Yanhong;WEN Xiaoyan;NI Li(Institute of Food Science and Technology,College of Biological Science and Engineering,Fuzhou University,Fuzhou 350108,China)

机构地区：[1]福州大学生物科学与工程学院,食品科学技术研究所,福建福州350108

出　　处：《食品科学》2018年第17期8-13,共6页Food Science

基　　金：国家自然科学基金青年科学基金项目(31201287);福建省自然科学基金项目(2015J05067);福建省教育厅项目(2016LSX);福州市科技计划项目(2016-G-54).

摘　　要：本研究以p UC57-α-gliadin重组质粒为对象进行同源性分析,构建表达质粒p ET-22b-α-gliadin,利用大肠杆菌(Escherichia coli)体外诱导表达α-醇溶蛋白,以体积分数70%乙醇溶液提纯,利用柠檬酸对α-醇溶蛋白进行脱酰胺改性,通过傅里叶变换红外光谱、内源性荧光扫描、扫描电子显微镜表征改性后α-醇溶蛋白的结构变化,通过质地剖面分析(texture profile analysis,TPA)实验探究其对面条质地的影响。结果表明:α-醇溶蛋白柠檬酸脱酰胺改性后α-螺旋结构含量减少,β-折叠结构含量增加,α-螺旋/β-折叠由1.00降为0.64,说明α-醇溶蛋白的分子柔韧性增加;α-醇溶蛋白的内源性荧光扫描结果显示λmax发生红移,说明α-醇溶蛋白的内部结构发生伸展,使内部的色氨酸暴露;扫描电子显微镜观察结果表明α-醇溶蛋白表面呈现光滑均匀的块状;TPA实验发现脱酰胺改性的α-醇溶蛋白使面条硬度降低,黏着性提高。The recombinant plasmid pUC57-α-gliadin was subjected to homology analysis in this study.The target gene was inserted into the expression vector pET-22b.The recombinantα-gliadin was successfully expressed and purified with 70%ethanol.Thisα-gliadin was then deamidated with citric acid.The deamidatedα-gliadin was characterized by Fourier transform infrared spectroscopy,endogenous fluorescence spectroscopy and scanning electron microscope(SEM).Meanwhile,its effect on the texture of noodles was investigated with a texture analyzer.Results showed thatα-helix content decreased whileβ-sheet content increased;α-helix/β-sheet ratio decreased from 1.00 to 0.64 after the deamidation ofα-gliadin indicating that the molecular flexibility of the deamidatedα-gliadin increased.The endogenous fluorescence spectrum showed a red shift inλmax,implying that the structure ofα-gliadin was extended,leading to exposure of tryptophan residues.The hardness and adhesiveness of noodles were respectively decreased and increased by adding deamidatedα-gliadin,which had a lump-like structure with a smooth and uniform surface as observed under SEM.

关 键 词：α-醇溶蛋白 体外克隆表达 脱酰胺改性 面条机械特性 

分 类 号：TS201.2[轻工技术与工程—食品科学]