Optimization of Dietary Fiber Extraction from Sweet Potato Residue from Ethanol Fermentation Using Response Surface Methodology

Response surface methodology was used to optimize the enzymatic extraction of dietary fiber from sweet potato residue after ethanol fermentation by using alkali protease. The results showed that the optimal extraction conditions were obtained as follows: enzyme dosage,0.45%(m/m),extraction time,3 hours and ratio of water to material,9.5:1; pH,8.0 and temperature,55℃. Under these conditions,the yield of dietary fiber was 31.38% and the removal efficiency of protein was 85.92%. The proximate composition of dietary fiber showed that the content of total dietary fiber was 58.74%. The total dietary fiber was mainly composed of insoluble dietary fiber.