Abstract: The high content of pigment makes it difficult to crystallize raffinose from its ethanol solution obtained from defatted wheat germ. In the present study, activated charcoal (AC) was used to develop a method for decolorizing raffinose solution, and the decolorization conditions AC dose, temperature, pH and operation time were optimized by single factor experiments, where the effects of the four conditions on decolorization rate were preliminarily, in combination with a response surface design involving 3 factors (AC dose, temperature and pH) at 3 levels. The optimum decolorization conditions were determined as follows: AC dose, 4 g/100 mL; temperature, 50 ℃; pH, 5.0; and adsorption time, 2 h. Under these conditions, the decolorization rate was up to 94.6%, and a very small amount of raffinose was lost. Therefore, active carbon is applicable to decolorization of raffinose.

Key words: defatted wheat germ, raffinose, activated charcoal, decolorization, response surface analysis (RSA)