Determination of interaction of urea and soybean protein isolate by fourier transform infrared spectroscopy

FTIR spectroscopy was applied to investigate the interaction of urea and soybean protein isoltes (SPI).Amide bandⅢof SPI was analyzed to obtain the change in secondary structure of SPI when different concentrations of urea were added.At 0.1 mol·L~(-1) concentration of urea,the content ofβ-sheet decreased and the content of random coil increased.With the concentration of urea increasing, theβ-sheet increased and the random coil decreased.The contents ofα-helix andβ-turn increased at first and then decreased with the concentration of urea increasing.