Abstract:The effects of solid-liquid ratio，extraction solvent pH，microwave time，and microwave power on pectin polysaccharide yield from broccoli stalks were investigated using the microwave-assisted acid method.In addition，the extraction conditions were optimized by performing single factor experiments and response surface analysis（RSM）based on Box-Behnken design.The results showed that the four factors had significant effects on pectin polysaccharide yield，with the extraction solvent pH and microwave power being the most significant factors.The order of factors influencing pectin polysaccharide yield was extraction solvent pH＞microwave power＞solid-liquid ratio＞microwave time.The RSM was reliable，and the optimal extraction conditions were as follows:solid-liquid ratio of 1∶21（g/mL），extraction solvent pH of 1.7，microwave time of 7.0 min，and microwave power of 900W.Pectin polysaccharide yield was（4.88 ± 0.00）% under the optimal extraction conditions，with a relative error of 0.03% when compared with the predicted value.The present study provided an experimental basis for the comprehensive utilization of broccoli by products and the exploitation of high-quality pectin sources in China.