米糠谷蛋白与β-环状糊精热聚集对乳化性质和结构特性的影响

Effects of Thermal Aggregation Behavior of Rice Bran Gluten andβ-cyclodextrin on Emulsifying Properties and Structural Properties

为提高米糠谷蛋白功能性质,本研究对米糠谷蛋白与β-环状糊精进行复合热处理(温度60、70、80、90、99℃,时间40、80、120、160、200 min),分析复合聚集体的浊度、接枝度、乳化性质及结构特性等,探究米糠谷蛋白与β-环状糊精复合热聚集行为。结果表明,米糠谷蛋白与β-环状糊精在90℃条件下加热复合160 min时,复合聚集体乳化活性指数达到最大,与天然米糠谷蛋白相比提高了2.39倍;在80℃条件下加热复合200 min时,复合聚集体乳化稳定性指数最大,与天然米糠谷蛋白相比提高了2.39倍。复合物在80℃条件下受热后,米糠谷蛋白与β-环状糊精结合生成较大颗粒的聚集体;复合物中米糠谷蛋白肽链结构打开,游离巯基含量增加,二硫键断开,疏水基团暴露,β-折叠向α-螺旋和β-转角转化,以共价键的形式形成分子间氢键,使得复合聚集体分子更好地结合到油水的界面,复合聚集体乳化活性和稳定性显著提高(P<0.05)。本研究结果为后续米糠蛋白质功能性质的改善及米糠蛋白质的深加工提供了理论依据。

In order to improve the functional properties of rice bran glutenin,rice bran glutenin andβ-Cyclodextrin were heated to combined at 60,70,80,90,99℃for 40,80,120,160,200 min.The turbidity,grafting degree,emulsifying properties and structural properties of the composite aggregate were analyzed to explore the thermal aggregation behavior of rice bran glutenin andβ-cyclodextrin.The results showed that when the complex reaction of rice bran gluten andβ-cyclodextrin was heated at 80℃for 160 min,the emulsification of the complex aggregates reached the maximum,which was 2.39 times higher than that of natural rice bran gluten.When heated at 80℃for 200 min,the emulsion stability of the composite aggregates reached the maximum,which was 2.39 times higher than that of natural rice bran gluten.The rice bran glutenin combined withβ-cyclodextrin formed large particles aggregates under this temperature.In the complex,the structure of the rice bran gluten peptide chain was opened,the content of free sulfhydryl groups increased,the disulfide bonds were broken,and the hydrophobic groups exposed.β-sheets of rice bran glutenin transformed intoα-helices andβ-turns to form intermolecular hydrogen bonds in the form of covalent bonds.This would make the complex aggregate molecules easier adsorpted to the oil-water interface,and the emulsifying activity and emulsifying stability of the complex aggregate were significantly improved(P<0.05).These results provided theoretical basis for the subsequent improvement of the functional properties of rice bran protein and the deep processing of rice bran protein.