Response Surface Methodology-Optimized Pilot-Plant Extraction of Polysaccharides from Mulberry Leaves

Traditional solvents method and response surface methodology (RSM) for the pilot plant extraction of polysaccharides from mulberry leaves were studied. The effects of three extraction factors (temperature, extraction time and sample: solvent ratio) on the yield of polysaccharides were examined. Three factors-three level Box-Behnken response surface design (BBD) coupled with RSM were used to find the optimal experimental conditions by reducing the number of experiments performed. The results indicated that the optimum pilot-plant conditions for the extraction of polysaccharides are a temperature of 76.7 degrees C, an extraction time of 1.87 h (112.2 min) and a sample: solvent (distilled water) ratio of 1: 20.6. The actual measured concentration under these optimized conditions is 105.57 mg/g polysaccharide crude product and is basically consistent with the predicted value of 106.64 mg/g. These show that the BBD coupled with RSM to model the pilot plant process of polysaccharides from mulberry leaves were accurate and reliable. The pilot-plant results are compared with those of the laboratory extraction which lay the foundation for the industrial application.