Optimization of decolorization technology of okra polysaccharides by response surface methodology

The decolorization condition of polysaccharides from okra was optimized using macroporous resin HP-20 by response surface methodology. The effects of sample concentration, pH, decolorization temperature and decoloration condition on decolorization rate and retention rate was studied by single test.Based on the results, a mathematical model was built by means of Box- Behnken design to analyze the relationship between the influencing factors and decolorization rate, retention rate of the polysaccharide respctively.The optimum conditions of macroporous resin HP-20 for static decolorization were as follows: sample concentration was 9.8mg /mL, pH was6.0, decolorization temperature was 20℃ and decolorization time was 7h. Under the optimal conditions, a decolorization rate of 91.07% and polysaccharide retention rate of 85.52% were obtained, of which the relative errors were 0.53% and 0.54% respectively. Decolorization made okra polysaccharides with better color, while protein was removed without changing polysaccharide solubility. And the predictability of the mathematic model was good, which could be used for practical guidance.