水热糖基化大米蛋白质的结构以及溶解性研究

以大米蛋白质(RP)与木糖为原料,采用水热糖基化的方法,研究在不同反应时间、pH、木糖与RP质量比条件下,糖基化产物接枝度与溶解度的关系,并对反应条件为:温度120℃,时间为20 min,pH为8,木糖与RP质量比为7:1的RP-木糖糖基化产物的溶解性与结构变化之间的关系进行探讨。得出RP-木糖糖基化产物溶解度由11.35%增加到27.62%,接枝度达到46.5%。氨基酸组成、电泳、荧光光谱、紫外光谱、红外光谱结果表明:RP的谷蛋白聚肽、球蛋白亚基和谷蛋白碱性亚基中精氨酸、赖氨酸可能与木糖发生共价结合生成了可溶性聚集体;二级结构中α-螺旋、β-折叠减少,无规则卷曲增加。因此,水热糖基化反应使RP的溶解性质得到改善。

Structure and Solubility of Rice Protein by Hydrothermal Cooking with Glycosylation

Rice protein(RP) and xylose were used as raw materials by hydrothermal cooking with glycosylation. The relationship between grafting degree and solubility of glycosylated products was studied under different reaction conditions. The structure of RP xylose glycosylated products was characterized under the conditions of reaction temperature 120℃,reaction time 20 min,pH value 8 and mass ratio of xylose to RP 7:1.The relationship between solubility and structure change was discussed. The solubility of RP xylose glycosylated products increased from 11.35% to 27.62%,and the grafting degree was 46.5%.The results of amino acid composition,electrophoresis,fluorescence spectrum,UV spectrum and FTIR showed that the soluble aggregates might be formed by the covalent binding of arginine and lysine in glutelin polypeptide,globulin subunits and basic subunits of glutelin in RP with xylose. And the α-helix and β-fold in the secondary structure reduced,and the irregular curl increased. Therefore,the hydrothermal glycosylation improved the solubility of RP.