关键词: 大分子拥挤, 大豆分离蛋白, 葡聚糖, 共价键, Maillard 反应

Abstract:

In order to explore the covalent modification of proteins by polysaccharide chains,soy protein isolate ( SPI) -dextran conjugate ( SDC) was prepared via the Maillard reaction in macromolecular crowding conditions. Then,the functions and conformation of the product were analyzed by means of the sodium dodecyl sulfate-polyacrylamide gel electrophoresis,the fluorescence spectroscopy,the gel permeation chromatography and the circular dichroism spectroscopy. The results show that ( 1) there occurs a covalent binding of dextran to SPI after the Maillard reaction best being carried out with a SPI-to-dextran mass ratio of 1: 1 at 60℃ for 30 h; ( 2) as compared with the SPI-dextran mixture without the Maillard reaction,SDC possesses less hydrophobic groups on its surface and stronger emulsifying activity in macromolecular crowding conditions; ( 3) SDC is more thermally stable than SPI; and ( 4) the covalent binding of polysaccharides changes the structure of SPI and improves the structural flexibility,which benefits the function display of SPI.

Key words: macromolecular crowding, soybean protein isolate, dextran, covalent bonds, Maillard reaction