基于气流分级诱导的组分重组提升发芽小麦粉面筋蛋白品质的机理研究

Sprouting has a deteriorating effect on the processing and edible quality of wheat. Previous studies have found that air classification could improve the gluten quality of sprouted wheat flour, but the mechanism of this phenomenon is still unclear. Therefore, this project takes the sprouted wheat flour classified by air classification as the research object, through the comprehensive evaluation of the gluten protein quality, the effects of component recombination induced by air classification on gluten protein quality will be investigated. By investigating the effects of component recombination on gluten composition (protein/subunit type, molecular weight distribution, content and proportion) of sprouted wheat flour, the intrinsic correlation between gluten composition and its main quality indexes will be established, and the key protein/subunit components causing the deterioration of gluten quality of germinated wheat flour will be analyzed. By Fourier Transform Infrared Spectroscopy (FTIR), Circular Dichroism (CD) and Raman Spectra (RS), the structure of key protein/subunit components will be nvestigated, then the intrinsic reason of air classification on the quality of gluten protein in sprouted wheat flour will be clarified from the molecular level. By High Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS), Fluorescence Probe Method, Periodic acid-Schiff staining, Nuclear Magnetic Resonance (NMR), Scanning Electron Microscope (SEM) and Confocal Laser Scanning Microscope (CLSM), the crosslinking behavior of protein in gluten system and the microphysical state of gluten will be studied. And then the mechanism of improving gluten quality of germinated wheat flour based on air classification-induced component recombination will be further revealed, which could provide a theoretical basis for improving gluten quality of sprouted wheat flour and value utilization of sprouted wheat flour.

发芽对小麦的加工品质和食用品质具有劣化影响，前期研究发现气流分级可提升发芽小麦粉的面筋品质，但该现象产生的机理尚不清楚。因此，本项目以气流分级后发芽小麦粉为研究对象，通过对其面筋蛋白的品质进行综合评价，明确基于气流分级诱导的组分重组对面筋蛋白品质的影响规律；探讨组分重组对发芽小麦粉面筋组成（蛋白/亚基种类、分子量分布、含量和比例）的影响，建立面筋蛋白的组成及其主要品质指标的内在相关性，解析导致发芽小麦粉面筋蛋白品质劣变的关键蛋白/亚基组分；借助FTIR、CD、RS等手段分析关键蛋白/亚基组分的结构，从分子层面阐明发芽小麦粉面筋蛋白品质改变的内在原因；采用HPLC-MS、荧光探针法、PAS染色法、NMR深入研究面筋体系中蛋白的交联行为，结合面筋微观结构的分析，进一步揭示基于气流分级诱导的组分重组提升发芽小麦粉面筋蛋白品质的机理，为发芽小麦粉面筋品质的提升和发芽小麦粉的高值化利用提供理论依据。

发芽对小麦的加工品质和食用品质具有劣化作用，造成了巨大的经济损失。本项目以发芽小麦粉（SWF）为研究对象，通过气流分级将其分为三种粉，F1（>45 μm）、F2（20–45 μm）和F3（<20 μm），并对其面筋蛋白的品质进行综合评价。首先，明确了基于气流分级诱导的组分重组对面筋蛋白品质的影响规律；其次，探讨了组分重组对发芽小麦粉面筋组成和结构的影响，建立了面筋蛋白的组成和结构及其主要品质指标的内在相关性，解析了导致发芽小麦粉面筋蛋白品质劣变的关键蛋白/亚基组分；然后，通过分析面筋蛋白的化学作用力、与水的相互作用、热力学特性，从分子层面阐明了发芽小麦粉面筋蛋白品质改变的内在原因；最后，深入研究了面筋体系中蛋白的交联行为，结合面筋微观结构的分析，进一步揭示基于气流分级诱导的组分重组提升发芽小麦粉面筋蛋白品质的机理。主要研究结果如下，1、相比SWF，基于气流分级诱导的组分重组提高了F1的面筋蛋白品质，及其流变学特性、发酵特性、烘焙特性和蒸煮特性，而F3具有相反的表现。2、气流分级诱导的组分重组使F1富集了更多优质蛋白，其HMW-GS、大粒径GMP、二硫键、β-转角含量以及α-螺旋/β-折叠的比值较高，内部交联聚合紧密度和二级结构稳定性也较高。3、相关性分析和因子分析结果表明，蛋白质的组成是流变学特性的主要影响因素，而蛋白质的二级结构对发酵特性影响较大。4、F1氢键含量较高，离子键含量和疏水相互作用较低，因此面筋结构稳定性、强度和弹性升高。5、F1表面疏水性、变性转变温度和变性焓较高，说明其变性程度下降，有序性提高。6、F1自由水含量下降，结合水含量高，说明其交联增加，流动性减少，面筋网络结构得到了改善。7、相比F2和F3，糖类与F1交联更少，避免了面筋网络结构的弱化。7、面筋蛋白微观特征分析证实，F1重组粉面团网络结构连续性和致密性得到了明显改善。本项目为发芽小麦粉面筋品质的提升和发芽小麦粉的高值化利用提供了理论依据。