The dark colour of soybean oligosaccharides extract from sweet slurry, a byproduct of soybean sheet production
limits its full utilisation in the food industry. Adsorption resins were performed to remove the
coloured impurity. The effects of operation parameters on decolourisation efficiency and adsorption isotherm
were investigated. The experimental results revealed that more than 70% of the coloured impurity
was removed in final products by macroporous resin DM-130 after 24 h contact. Temperature had significant
influence on adsorption. The adsorption process and the thermodynamic data indicated that the
process was possibly exothermic and spontaneous. The optimum ratio of resin mass/oligosaccharides
solution was approximately 0.13 g/ml. The adsorption isotherm agreed with Freundlich model, indicating
that the adsorption process was monolayer and heterogeneous. Adsorption kinetics fitted the pseudosecond-order
kinetic model. The second step of intra-particle diffusion would be the rate-controlling step