大豆球蛋白自组装聚集及凝胶特性

Research of Soybean Proteins Self-assembly Fibrils and Their Gelation Properties

研究了在低pH值、低离子强度下,分别加热诱导不同浓度11S(大豆球蛋白)和7S(大豆伴球蛋白)自组装纤维化聚集体的形成。通过平均粒径和Thioflavin T(硫磺素T)荧光光谱,对自组装纤维化聚集体的性质进行表征,并对其热致凝胶的流变学,硬度和微结构特性进行考察。结果表明:在低pH值、低离子强度的诱导条件下,蛋白浓度对自组装聚集的形成起着关键作用,随着诱导浓度的增大,蛋白的纤维化聚集越明显,7S比11S更容易形成纤维化聚集。在酸性环境下,大豆球蛋白的纤维化聚集程度越高,越有利于热致凝胶网络结构的形成。在相同的预处理条件下,11S自组装凝胶硬度强于7S。扫描电镜结果显示7S自组装凝胶的网络结构较11S致密,但有序性较11S低。

The self-assembly fibrillar aggregations of soy glycinin and β-conglycinin at pH 2.0, 85 ℃ with vari-ous protein concentrations were investigated using dynamic light scattering （DLS） and Thioflavin T fluorescence tech-niques. The heat-induced gelation properties including rheology, hardness and network structure of different fibrillar aggregations were characterized simultaneously. The results showed that protein concentration played an important role in the self-assembly aggregate formation at low pH and low ionic strength. The data suggested fibrillar aggregation pro-gressively increased with the increasing of protein concentration. β-Conglycinin exhibited a higher ability to form ther-mally fibrillar aggregates than glycinin. The increasing degree of fibrillar aggregate was favorable for enhancing the network structure of heat-set gels. The hardness of glycinin fibril gel was stronger than that of β-conglycinin. Scanning electron microscopy observation indicated that the network of β-conglycinin fibril gel was more compact than glycinin, while the latter one was more in order.