Optimization of microwave-assisted extraction of insoluble dietary fiber (IDF) from Rosa roxburghii by response surface method

Insoluble dietary fiber( IDF) was extracted from Rosa roxburghii by microwave- assisted extraction method.Based on the results of single factor experiments,the extraction procedure was optimized using response surface methodology( RSM) and Design- Expert V8.0.6 software.The order of influencing factors of IDF yield was:extraction temperature > the power of microwave > liquid- to- solid ratio > microwave- assisted extraction time. The optimum extraction conditions were as follows: the microwave power of 345 W/ g; extraction temperature of 63 ℃;microwave- assisted extraction time of 12 min; and liquid- to- solid ratio of 20 m L / g. Under the above optimum extraction conditions,the actual yield of IDF from Rosa roxburghii was 80.02%. The relative standard deviation between theoretical and practical yields was 0.22% and the results demonstrated a good reproducibility,indicating the effectiveness and reliability of RSM model.