Abstract: The removal of the heavy metal cadmium in dried Lentinus edodes using citric acid content was optimized using a combination of one-factor-at-a-time method and response surface methodology. The removal efficiency of cadmium was investigated as a function of three independent variables: citric acid concentration, pH and rotation speed. It turned out that the maximum removal rate of cadmium of 57.0% was obtained under the following optimized conditions: citric acid concentration 0.32 mol/L, pH 5.0, and rotation speed 70 r/min. After the treatment, the maximum residual cadmium content was 0.41 mg/kg, lower than the national limit of 0.5 mg/kg. Meanwhile, low losses of polysacccharides and proteins were observed suggesting good retention of nutrients in L. edodes. The proposed method could have a high application potential for reducing residual cadmium in L. edodes.

Key words: Lentinus edodes, cadmium, citric acid, response surface methodology