摘要
为了研究挤压和糖接枝改性的方法对大米蛋白功能性及结构的变化的影响,本文研究了不同挤压条件下挤压的大米蛋白与葡聚糖的糖接枝反应,分析了不同挤压改性的大米蛋白对糖接枝反应接枝度的影响,根据单因素试验优化反应条件,在挤压温度90℃、大米蛋白水分含量35%,螺杆转速200 r/min的条件下挤压的大米蛋白与葡聚糖接枝得到的复合物,接枝度最大为(17.6±0.3)%,试验测定接枝度为(17.6±0.3)%共聚物的溶解性和乳化性及表面疏水性。结果表明,与天然大米蛋白相比,挤压的大米蛋白与葡聚糖接枝复合物的溶解性在较宽的范围内显著增加,增加了8.4%~76.6%,乳化性和乳化稳定性分别增加了62.2%和73.9%,表面疏水性降低了69.5%。同时,试验通过傅里叶红外光谱、SDS-PAGE电泳、扫描电镜等方法和手段分析了大米蛋白亚基结构及表面结构特征。结果表明,挤压糖接枝反应显著改变了蛋白亚基结构,α-螺旋、β-转角和无规卷曲结构含量分别增加了24.4%、26.0%和19.9%,而β-折叠结构含量减少了15.0%,SDS电泳分析结果显示挤压后大米蛋白与葡聚糖接枝反应物的条带51.0 ku和80 ku^82 ku亚基带变得模糊,并且在分离胶和浓缩胶分理处出现大分子量分子,说明有共价连接大分量聚集物生成,扫描电镜分析了表观结构变化,表明挤压和糖接枝对蛋白结构改变显著。
In order to prepare a high solubilizing and emulsibity rice protein, the method wet-heating grafting reaction of extruded rice protein and dextran was uhilized to study the influence of barrel temperature, the material moisture content and screw speed on the degree of substitution. The optimal process conditions were determined through single factor experiment analysis： barrel temperature 90℃, 35 % moisture content of material, screw speed 200 r/min, Under this condition, the degree of substitution reached at （ 17.6±0.3 ） %. The solubility and emulsification, surface hydrophobicity of extruded rice protein-dextran conjugates on the degree of substitution of （ 17.6±0.3 ） % was investigated, the results showed that compared with the native rice protein, the sol- ubility of extruded rice protein and dextran conjugates increased significantly in a wide range, increased by 8.4 %-76.6 %, the emulsification activity and emulsification stability increased by 62.2 % and 73.9 %, respectively, the surface hydrophobicity decreased by 69.5 %. Meanwile, experiment analyzed subunit structure and molecular weight changes and apparent characterization of rice protein by the methods and means of Fourier infrared spectrum and SDS-PAEG electrophoresis and SEM, the results analysis showed that extrusion and grafting reaction changed the structure of protein subunits significantly, the content of a-helix and 13-turn and random coil increase by 24.4 %, 26.0 % and 19.9 % ,respectively, and 13-sheet structure content decreased by 15.0 %, significantly, SDS electrophoresis analysis results showed that the extruded rice protein and dextran conjugates the line of 51.0 ku and 80 ku-82 ku become blurred, a high molecular weight appeared in the region between acrylamide separating gel with acrylamide stacking gel, indicated molecular weight have happened a big weight aggregates of covalent connection, the SEM analysis of the apparent structure, indicated the graft reaction and s extrusion modified protein structure significantly.
出处
《食品研究与开发》
CAS
北大核心
2016年第15期122-129,共8页
Food Research and Development
基金
国家星火重点项目(2015GA650007)
辽宁省高等学校优秀科技人才支持计划(第一层次)资助专项(LR2015062)
辽宁省组织部"百千万人才工程"百层次人选资助专项(2013B028)
关键词
大米蛋白
葡聚糖
糖接枝反应
挤压
功能性质
结构表征
rice protein
dextran
graftingreaction
extrusion
functional properties
structuralcharaeterization
