【摘要】 实验采用流变仪、傅里叶变换红外(FTIR)、扫描电子显微镜(SEM)研究不同浓度κ-卡拉胶对面筋蛋白持水性、黏弹性、二级结构及超微结构的影响。结果表明,随着卡拉胶添加量的增加,面筋蛋白的持水性呈上升趋势,当卡拉胶的添加量达到0.9%时,持水性从原样品的103%增加至129%;而同时储能模量(G’)和损耗模量(G’’)都有明显的增加,体系的G’始终大于G’’,具有典型黏弹性流体的特性。添加卡拉胶后面筋蛋白β折叠含量几乎不变,而α螺旋含量下降5%,β转角含量上升4%,说明卡拉胶的添加导致α螺旋向β转角的转化,但随着卡拉胶添加量的增加,面筋蛋白结构几乎不再发生变化。SEM中面筋蛋白呈现网络状结构,孔洞分布和大小都比较均匀,其直径为(10~15)μm,随着卡拉胶浓度的增加,网孔直径下降,有球状分离物醇溶蛋白的出现,且醇溶蛋白直径随着卡拉胶浓度的上升而下降。更多还原

【Abstract】 In this paper, the effect of adding the different concentration of κ-carrageenan on the water binding capacity, rheological properties, secondary structure and microscopic property of gluten were studied by the Rheometer, Fourier Transform Infrared Spectroscopy(FTIR) and Scanning Electron Microscopy(SEM). The results showed that water binding capacity, storage modulus(G’) and loss modulus(G") of the gluten increased with the increasing of κ-carrageenan concentration. The water binding capacity increased from 103% for the control to 129% for the gluten added the κ-carrageenan for 0.9%. The G’ is higher than G" of the gluten added κ-carrageenan leading to the mixed system dominated by elastic, showing the typical "weak gel" properties. After the adding κ-carrageenan(0.3%), for the gluten many changes in the secondary structure could be detected, there is a significant decrease in α-helix content(5%) with simultaneous increase in β-turn content(4%), which means the α-helix was converted into β-turn. However, there was no change in the secondary structure with the increasing of κ-carrageenan concentration. SEM photographs showed that the gluten chain formed network with homogeneous meshes measuring(10~15)μm, while the diameters of the meshes decreased by the adding κ-carrageenan. Some separated prolamin beside the glutenin chains was also observed in the SEM images.更多还原