微波合成大豆蛋白-糖接枝物结构表征

Structural characterization of soy protein-saccharide grafts synthesized by microwave

以大豆分离蛋白(SPI)、乳糖及可溶性淀粉(SS)为主要原料,利用微波辐射的方法合成SPI-糖接枝物,对其分子进行结构表征:傅立叶红外(FTIR)证明了SPI是以共价键的结合形式引入了糖分子。从SPI-乳糖的核磁共振(13C-NMR)图谱可以得出,接枝物中乳糖是以葡萄糖单元C1、C2及C3参与成键。圆二色(CD)分析表明,与SPI相比,SPI-糖接枝物的α-螺旋含量减少;无规则卷曲含量增加。扫描电子显微镜(SEM)研究发现,SPI分子的表面结构与其接枝物有明显不同,尤其是SPI-SS接枝物聚集体分散开来。通过动态激光光散射(DLS)分析表明,接枝物溶液的粒径较SPI小。

The soy protein isolate（SPI）, lactose and soluble starch（SS） were used as the main materials, and SPI-saccharide grafts were synthesized by the microwave radiation in order to study the changes of their structural characterization. According to the analysis of FITR, the SPI molecule was grafted with the saccharide molecule by the covalent bond. And by the 13C-NMR, the C1, C2 and C3 of the glucose in the lactose were take part in the form bonds with SPI. In comparison with SPI, the content of α-helical conformation in the secondary structure of SPI-saccharide graft, which was detected by CD, decreased, but that of random structure increased. Moreover, it was observed with SEM that the surface structure of SPI was different with SPI-saccharide graft, whose aggregates were dispersed, especially for SPI-SS graft. In addition, through dynamic laser scattering, the particle size of the graft solution was less than that of SPI solution.