Optimization of Microwave-Assisted Extraction of Water-Soluble Dietary Fiber from Zingiber striolatum Diels Fruits by Response Surface Methodology

The microwave-assisted extraction of water-soluble dietary fiber(SDF) from Zingiber striolatum Diels fruits was optimized by response surface methodology. An experimental design was carried out involving four variables at three levels each. An extraction time of 151.4 s with a microwave power of 264 W using sulphuric acid solution at pH 3.65 as the extraction solvent with a solid-to-solvent ratio of 1:33(g/mL) was found to be optimal. Experiments carried out under the optimized conditions resulted in an extraction yield of 5.52%, agreeing with the predicted value(5.75%). The extraction procedure presented in this study is characterized by time saving, low energy consumption and high extraction efficiency.