Shan Shengyue, Chen Da, Federici Enrico, Jones Owen G, Campanella Osvaldo H
Department of Food Science and Technology, The Ohio State University, Columbus, OH, United States.
Department of Animal, Veterinary and Food Sciences, University of Idaho, Moscow, ID, United States.
Front Nutr. 2022 Jul 29;9:909877. doi: 10.3389/fnut.2022.909877. eCollection 2022.
The increasing awareness of the celiac disease, an autoimmune disorder caused by the consumption of products containing gluten, has led to a growing interest in the development of gluten-free bakery products. In this study, whey protein fibrils (WPFs) were incorporated to mimic the fibrous network of gluten. The rheological properties and microstructure of the developed gluten-free doughs were evaluated and compared with gluten doughs. Protein fibrils were prepared by heating a whey protein isolate (WPI) solution at 80°C in an acidic environment with low salt concentration, and then the fibril lengths were adjusted by leveling up the solution pH to 3.5 and 7. The dimensions of the fibrils were measured by atomic force microscopy (AFM). Rice and potato starches were mixed with fibrils, WPI, gluten, or without protein, to form different doughs for further investigation. Shear tests, including stress sweep, frequency sweep, and creep recovery, were performed to study the viscoelastic properties of doughs under small or large deformation. The strain-hardening properties of doughs under biaxial extension were studied by the lubricated squeezing flow method. The microstructure of the doughs was characterized by cryo-scanning electron microscopy (cryo-SEM). Compared with doughs prepared with WPI and no proteins, doughs incorporating fibrils showed comparable linear viscoelasticity to gluten dough tested with stress sweep, frequency sweep, and creep recovery in the linear viscoelastic region. More differences between the protein fibril doughs were revealed in the rheological properties in the non-linear region. Creep recovery parameters, such as compliance, elastic moduli during the creep, and recovery stages of gluten dough, were like those of WPF pH7 dough, but significantly different from those of the WPF pH3.5 dough. Strain-hardening properties were found in the WPF pH7 dough, although not in WPF pH3.5 dough. Microstructural characterization showed that both fibrils prepared with the different conditions formed a continuous protein phase for the improvement of dough cohesiveness, but the structure of the phase was different between the two fibrils. To summarize, whey protein fibril at pH 7 seemed to have the potential of being used as an ingredient with similar functions to gluten in gluten-free bakery products.
乳糜泻是一种因食用含麸质产品引发的自身免疫性疾病，随着人们对其认识的不断提高，无麸质烘焙产品的开发越来越受到关注。在本研究中，加入乳清蛋白原纤维（WPFs）以模拟麸质的纤维网络。对所制备的无麸质面团的流变学特性和微观结构进行了评估，并与含麸质面团进行了比较。通过在低盐浓度的酸性环境中将乳清蛋白分离物（WPI）溶液加热至80°C来制备蛋白原纤维，然后将溶液pH值调至3.5和7来调整原纤维长度。通过原子力显微镜（AFM）测量原纤维的尺寸。将大米淀粉和马铃薯淀粉与原纤维、WPI、麸质或不添加蛋白质混合，形成不同的面团用于进一步研究。进行了剪切试验，包括应力扫描、频率扫描和蠕变恢复试验，以研究面团在小变形或大变形下的粘弹性特性。通过润滑挤压流动法研究了面团在双轴拉伸下的应变硬化特性。通过低温扫描电子显微镜（cryo-SEM）对面团的微观结构进行了表征。与用WPI和不添加蛋白质制备的面团相比，加入原纤维的面团在应力扫描、频率扫描和线性粘弹性区域的蠕变恢复试验中显示出与含麸质面团相当的线性粘弹性。在非线性区域的流变学特性方面，蛋白原纤维面团之间的差异更为明显。蠕变恢复参数，如柔量、蠕变过程中的弹性模量以及含麸质面团的恢复阶段，与WPF pH7面团相似，但与WPF pH3.5面团有显著差异。在WPF pH7面团中发现了应变硬化特性，而WPF pH3.5面团中没有。微观结构表征表明，在不同条件下制备的两种原纤维均形成了连续的蛋白相，以改善面团的内聚性，但两种原纤维的相结构不同。总之，pH 7的乳清蛋白原纤维似乎有潜力在无麸质烘焙产品中用作具有与麸质类似功能的成分。
