The preparation and physical characterisation of modified soybean polysaccharides

A novel and facile method for modification of soybean polysaccharides was applied. This involved a swelling water‐solvent exchange technique. A series of stearoylated soybean polysaccharides was prepared under homogeneous reaction conditions in an N,N‐dimethylformamide/lithium chloride system by reaction with stearoyl chloride using 4‐dimethylaminopyridine as catalyst and triethylamine as acid acceptor. At a reaction temperature of 80 °C and time of 30 min, approximately 1 mol of the soybean polysaccharides, when reacted with 3 mol of reagent, resulted in an 85% yield. The products were characterised by Fourier transform infrared spectroscopy (FT‐IR), elemental analysis and thermogravimetric analysis. It was found that the modified soybean polysaccharides had improved thermal stability and enhanced solubility in organic solvents compared with their unmodified counterparts. © 2002 Society of Chemical Industry