大麦β-葡聚糖微凝胶热诱导融渗影响面筋蛋白交联反应的机理研究

Barley, the fourth highest yielding grain, is rich in beta glucan and in extremely wide application prospect. Barley beta glucan (BBG) is viscous in water system and easy to form thermal-reversible gel induced by lowering the temperature. Thus BBG reduced the viscoelasticity of dough and damaged the quality of gluten, which limited the application of BBG. So how BBG influence the gluten crosslinking become stringent to be realized. As reported in previous studies, most researchers focused on the crosslinking level of gluten, while the characters of products were also depends on the crosslinking progress. Based on the previous studies, effect of barley beta glucan micro gel’s thermal inducted infiltrating on gluten protein cross-linking reaction and mechanism were summarized based on the study about gluten crosslinking progress. By the method of dynamic mechanical and dynamic microcalorimetric analysis, the structural, functional and thermal-chemical transforming regulation were studied during the BBG-gluten complexed 3-D net formation and BBG thermal inducted infiltrating progress. The changes in spatial structure of gluten during crosslinking process were determined by Raman spectroscopy and infrared spectroscopy. With 2-dimensional electrophoresis-mass spectrometry analysis and mass spectrometry-proteomics analysis, the specific protein subunits sensitive to BBG and key crosslinked active group in gluten were identified. The molecular mechanism of how BBG affect the crosslinking of gluten were summarized, and the critical control points in the progress of gluten crosslinking reaction were pointed out. The aim of this project is to provide theoretical references for the application of BBG in food industry.

大麦产量在谷物中占第四位并富含大麦β-葡聚糖(BBG)，极具应用前景。BBG具有高黏性，易形成冷致热可逆凝胶，使得添加BBG的面团黏弹性不足、面筋质量弱化，限制了其应用，因此BBG影响面筋蛋白交联的机理成为亟待解决的科学问题。现有研究多关注面筋蛋白交联聚合度，而面筋蛋白交联进程决定了交联产物的结构及功能。本项目基于前期研究，拟通过面筋蛋白交联反应进程来研究BBG微凝胶热诱导融渗影响面筋蛋白交联的机理。采用动态热机械、动态微量热等方法研究BBG热融渗及面筋蛋白复合网络形成过程中结构、功能变化规律和热化学变化规律；通过拉曼光谱、红外光谱研究交联过程中面筋蛋白空间结构的变化，并借助二维电泳和质谱联用、质谱和蛋白质组学联用等技术分析鉴定BBG影响的关键蛋白亚基及参与交联的活性基团，明确BBG影响面筋蛋白交联的分子机制和交联反应进程的关键控制点，为BBG在食品工业中的应用提供理依据。

大麦的全球产量在谷物中占第四位，并富含功能性β-葡聚糖，已经被美国FDA和欧盟批准了关于其降低血浆胆固醇、餐后血糖以及促进肠道健康等功效的健康声称。然而，BBG会弱化面筋网络结构，造成面制品质构变硬、口感粘腻、体积减小、色泽变暗等，BBG造成面制品感官品质的劣变是其在食品中应用的主要限制因素。因此，探讨BBG与面筋蛋白相互作用的机理，对BBG及面筋蛋白的开发利用具有重要意义。.项目组首先建立了高速离心涡旋破壁（HSCV）法对BBG进行提取，提高浸提效率并缩短浸提时间。随后研究了BBG对小麦粉糊化特性、面团流变性质以及面团在加热过程中热化学反应进程的影响，分析BBG对面筋蛋白质构弱化的机理。结果表明，BBG添加量在1%-5%时具有抑制淀粉糊化的作用，提高了小麦粉的糊化温度，降低了其峰值黏度、最低黏度、终值黏度。差示扫描量热（DSC）分析结果表明，添加BBG迟滞了面团中热化学反应，使其反应峰向高温区移动；高效液相凝胶色谱（SE-HPLC）分析结果显示添加BBG主要影响了麦谷蛋白和麦醇溶蛋白SDS可萃取性，对清蛋白和球蛋白影响较小。采用十二烷基磺酸钠-聚丙烯酰氨凝胶电泳（SDS-PAGE）分析面筋蛋白的亚基变化情况，发现BBG对不同相对分子质量面筋蛋白亚基的影响具有一定的选择性。通过分析加热过程中面团的荧光显微结构，发现BBG在面团中于低温下形成微凝胶，在加热过程中BBG微凝胶融化穿插到面筋网络结构中，阻碍了面团中的热化学反应进程，使淀粉糊化、蛋白变性交联等迟滞到更高的反应温度。最后，在明确了BBG影响面筋蛋白交联反应的机理的基础上，制备了BBG和面筋蛋白脂肪模拟物，有针对性的探究了三种热处理（热流化，微波和烘烤）对BBG理化特性、超微结构和抗氧化等营养特性的影响。.本项目在实施过程中，在国内外期刊上发表相关学术论文8篇，其中SCI收录7篇（5篇为top期刊）；培养博士研究生3名，硕士研究生3名；申请发明专利2项，授权1项。