谷朊粉糖基化改性对其结构及溶解性的影响

Structure and Solubility of Gluten-Polysaccharide Conjugates

本试验使用葡聚糖对谷朊粉进行干法糖基化改性。研究了反应温度、时间以及糖与谷朊粉的配比对反应接枝物溶解度的影响,优化了制备最佳溶解度接枝物的工艺条件。同时研究了接枝物在不同p H以及温度条件下的稳定性。并通过傅里叶红外光谱(FTIR)和电子显微镜(SEM)扫描方法证实了糖基化的发生及糖蛋白结构的变化。结果表明,在反应温度59℃,葡聚糖/谷朊粉(m/m)280%,反应时间12 d(288 h)的条件下接枝物的溶解度最高,为1.923 mg/m L。在p H较高或较低以及谷朊粉等电点等情况下,接枝物的功能特性均处于较高水平,且具有良好的稳定性。通过红外扫描分析可知,改性后蛋白质的二级结构发生了很明显的改变,其β折叠有所减少,α螺旋、转角结构的含量得到一定程度的增加,而糖基化改性对无规则卷曲结构的影响不大,通过电镜扫描分析可知,糖基化改性后蛋白质的分子体积增大。

In this experiment, the modification of gluten via dry - heated Maillard reaction with dextran was studied. The effects of reaction temperature, time and the ratio of sugar to gluten on the solubility of the protein - pol- ysaccharide conjugates were studied, and the process conditions for the preparation of glycoprotein with optimum solu- bility were optimized. The stability of the protein - polysaccharide conjugates at different pH and temperature was also studied. The glycosylation actions and the structure changes of the protein - polysaccharide conjugates were confirmed by infrared spectroscopy （FFIR） and scanning electron microscopy （SEM）. The results showed that the solubility of the protein - polysaccharide conjugates was highest of 1. 923 mg/mL under the reaction condition of the temperature 59℃, time 12 d（288 h） and dextran/gluten（m/m）280%. The functional properties of the modified protein were in a high level, and had good stability in the case of pH higher or lower, as well as the isoelectrie point of gluten. The infrared spectroscopy showed the structure of the modified protein had a very obvious change, including the decrease of β- fold, the increase of α - helix and β- turn structure at a certain degree. But the glycosylation had little effect on the Irregular coiled structure. The scanning electron microscopy showed that the volume of modified protein was increased.