小麦A、B淀粉颗粒理化性能差异的精细分子结构机制研究

There are significant differences in the physicochemical and functional properties between A- and B- wheat starch granules. Until now, the elaborate and systemic mechanisms of their difference in starch fine structure haven't been elucidated. In this project, A- and B- starch granules isolated from normal wheat, partial waxy wheat and waxy wheat varieties will be used to characterize and elucidate the influences of granule-associated proteins and lipid on their physicochemical, rheological and structural properties. The starch surface-associated proteins would be extracted from those three A- and B- starch granules wheat starch varieties, fractionated and identified by one-dimensional (1-D) SDS-PAGE, 2-DPAGE and ESI-Q-TOF MS/MS.Distinct locations of starch granule-associated proteins will be revealed using a protein-specific dye (3-(4-carboxybenzoyl) quinoline-2-carboxaldehyde) with confocal laser scanning microscopy (CLSM). The supramolecular structure of the A- and B-type granules of wheat starch will be revealed with the aid of confocal laser scanning microscopy (CLSM), small-angle x-ray scattering (SAXS) and transmission electron microscope (TEM), and atomic force microscope (AFM). A thorough working of this would lead to an appropriate knowledge of macromolecular structures difference between A- and B-type granules, and optimized to select a starch for specific applications.

小麦A、B型淀粉颗粒的理化性和功能性存在较大差异，但目前缺乏全面、系统的精细结构机制方面的研究。本项目拟选用普通小麦、部分糯小麦和糯小麦的A、B型淀粉颗粒作为研究材料，系统地研究淀粉颗粒结合蛋白与脂类物质分别对A、B型淀粉颗粒的理化性质、流变学性质和结构特征的影响。同时利用单向及双向SDS-PAGGE电泳技术、MALDI-TOF-MS分离技术等蛋白组学研究技术分别对A、B型淀粉颗粒蛋白进行定性研究，利用荧光生成试剂3?(4?羰基苯甲酰基)?喹啉?2?羰醛对颗粒结合蛋白染色后，结合激光共聚焦荧光显微镜（LSCM）技术，对其在淀粉颗粒中的分布状况进行分析。同时，结合激光共聚焦荧光显微镜、小角度X-衍射、透射电子显微镜和原子力显微镜等技术观察分析小麦A、B淀粉颗粒在超微结构方面的差异，揭示小麦A、B淀粉颗粒结构与性质的精细结构差异及其调节机制，也为小麦A、B淀粉的合理开发利用提供理论依据。

项目以硬质小麦、软质小麦和糯小麦A、B淀粉为研究材料，采用快速黏度分析仪、差示扫描量热仪和X-射线衍射仪，以及普光学显微镜、扫描电镜、偏光显微镜、激光共聚焦显微镜、原子力显微镜等显微技术系统分析比较了三类小麦A、B淀粉的理化性质和结构特征，研究表明小麦A、B淀粉间结构和理化性质方面存在较大差异，糯小麦和普通小麦之间理化性质换个结构也存在较为明显的差异。为探究淀粉颗粒结合蛋白与脂类对A、B淀粉的结构与理化性质方面的影响，对A、B淀粉进行了脱脂处理、脱蛋白处理和脱脂脱蛋白处理，并系统分析和比较了处理前后的小麦A、B淀粉的化学组成、形态结构和理化特性，探讨了脂类和蛋白质对小麦A、B淀粉颗粒理化特性及结构特性的影响，结果表明淀粉颗粒表面颗粒结合蛋白和脂类的存在对淀粉的结构和理化性质存在显著的影响。本项目的研究结果与结论对于增强小麦的加工品质和改进淀粉质食品的食用品质提供了理论依据，也是对已有淀粉科学研究方法的进一步实践探索和对淀粉科学与技术理论的深化与补充，同时也为进一步阐明小麦A、B 淀粉形态结构与性质差异的精细结构基础及其调节机制提供了数据支持。