Determination of the domain structure of the 7S and 11S globulins from soy proteins by XRD and FTIR

BACKGROUND The 7S and 11S fractions from soybean proteins have interesting high nutritional and excellent functional properties. The aim of this research was to improve the functional properties of soy proteins by studying the effect of bis(2-ethylhexyl) sodium sulfosuccinate (AOT) reverse micelles on the conformation of the 7S and 11S globulins using Fourier transform infrared and X-ray diffraction spectroscopy. RESULTS Fourier transform infrared revealed that the intensity of the 7S and 11S globulin bands from AOT reverse micelle extraction at 16001700, 14801575, 12201300, 3330, 1448 and 1395cm1 was higher than from aqueous buffer. X-ray diffraction data showed that the intensities of 7S globulin using two extraction methods at 2 about 10 degrees were significantly different (P < 0.05), about 22 degrees slightly increased. The intensities of 11S globulin at 2 about 10 degrees and 22 degrees were similar. The average distance between particles (dhkl) for 7S globulin with aqueous buffer extraction at 2 about 10 degrees was greater than AOT reverse micelle extraction. CONCLUSION This study showed the potential of reverse micelles as a protocol for extracting the 7S and 11S globulins for analytical purposes. The results represent a new avenue for determining the structures of the 7S and 11S globulins. (c) 2012 Society of Chemical Industry