Abstract: Objects: To research the optimization of reduction of toxicity by fermentation of rapeseed meals. Methods: A central composite rotatable design with two star points according to the principles of response surface methodology was adopted. The influences of pH, time, temperature, seed content and the ration of water to material and their interactions on the reduction of toxicity were valuated and the optimum variable combination for the highest reduction ratio was determined with the assistance of statistical software and the contour plots. Results: A good quadratic polynomial model was obtained. According to the ANOVA, the model was significant (p<0.0001) and there was no lack of fit. By analyzing the contour p lots generated by the model, the optimal levels for each variable were as follow: pH 5.1, time 47 h, temperature 29 ℃, seed content 6.2% and the ratio of water to material 2:1. On these conditions, the response value was up to 97%. Conclusion: the above results demonstrated that, otimization of reduction of toxicity by fermentation of rapeseed meals using RSM was reasonable and efficient. The obtained model was workable in present tested range.

Key words: rapeseed meals, reduce toxicity, solid fermentation, central composite rotatable design