超声复合碱处理对Oleosin蛋白结构及功能特性的影响  

Functional Characteristics of Oleosin Affected by Ultrasound-Assisted Alkali Treatment

作　　者：孙禹凡 齐宝坤[1,2,3] 钟明明 刘曌 杨树昌 李杨 SUN Yufan;QI Baokun;ZHONG Mingming;LIU Zhao;YANG Shuchang;LI Yang(School of Food Science,Northeast Agricultural University,Harbin 150030,China;Harbin Food Industry Research Institute,Harbin 150000,China;National Research Center of Soybean Engineering and Technology,Harbin 150000,China)

机构地区：[1]东北农业大学食品学院,黑龙江哈尔滨150030 [2]哈尔滨市食品产业研究院,黑龙江哈尔滨150000 [3]国家大豆工程技术研究中心,黑龙江哈尔滨150000

出　　处：《食品科学》2020年第7期79-85,共7页Food Science

基　　金：国家自然科学基金青年科学基金项目(31801579);中国博士后科学基金面上项目(2018M631902)。

摘　　要：为了改善蛋白质的功能特性,分析碱处理、超声处理、超声复合碱处理3种处理方式对Oleosin蛋白的结构及溶解性和乳化特性的影响,并深入探讨不同处理条件下蛋白聚集体的结构变化机理。采用原子力显微镜、动态激光散射、荧光光谱和圆二色光谱研究不同处理条件改性Oleosin蛋白的微观结构、流体动力学半径、内部结构特性和改性Oleosin蛋白空间结构的变化。结果表明:超声作用可以明显促进Oleosin蛋白的不溶性聚集体向可溶性聚集体转变,单独超声及超声复合碱处理使Oleosin蛋白溶解度相对于对照分别增加了124%和162%(P<0.05);圆二色光谱和荧光光谱结果表明,超声和碱作用均有助于蛋白质结构展开,从而促进更多的酪氨酸、色氨酸等疏水性基团暴露,与对照组相比,超声复合碱处理使Oleosin蛋白的α-螺旋相对含量增加17.7%,β-折叠相对含量减少9.2%;同时超声复合碱处理可降低Oleosin蛋白的颗粒粒径(286.0 nm)、提高乳化性(乳化稳定性指数575.0 g/m^2、乳化活性指数605.4 min)。本研究可为后期形成不同功能的改性Oleosin蛋白提供参考。In order to improve the functional properties of oleosin, the effects of alkali and ultrasonic treatments alone and in combination on the structure, solubility and emulsifying properties of oleosin were studied. The mechanism of structural changes of protein aggregates under different treatment conditions was also discussed. The microstructure, hydrodynamic radius, internal structure and spatial structure of modified oleosin were studied by atomic force microscopy, dynamic laser scattering, fluorescence spectroscopy and circular dichroism microscopy. The results showed that ultrasonic treatment could promote the transformation of oleosin from insoluble aggregates to soluble ones, and the solubility of oleosin subjected to ultrasonic treatment alone or in combined with alkali treatment increased by 124% and 162% compared to the control, respectively(P < 0.05). Circular dichroism and fluorescence spectroscopy showed that both ultrasonic and alkali treatments could promote the unfolding of protein structure, thus promoting the exposure of more hydrophobic groups such as tyrosine and tryptophan. Compared with the control group, the α-helix content of oleosin increased by 17.7% and the β-folding content decreased by 9.2% after the combined treatment. At the same time, the particle size decreased(286.0 nm) and the emulsifying properties improved(emulsion stability index of 575.0 g/m2, and emulsifying activity index of 605.4 min). This study provides a reference for improved functions of oleosin.

关 键 词：OLEOSIN 功能特性 超声 蛋白结构 

分 类 号：TS214.2[轻工技术与工程—粮食、油脂及植物蛋白工程]