Study on the Optimization of Extraction Process ofDietary Fiber from Sandouyin Soybean Dregs

【Objective】Sandouyin bean dregs was used as raw material to prepare dietary fiber. An single factor test and response surface method were used to optimize the extraction process. 【Method】 Based on single factor of acid extraction test, by using acid extraction water/solid ratio, acid extraction time, acid extraction temperature and acid extraction pH as response factors，and the extraction content of dietary fiber from bean dregs as response value, response surface method was used to obtain the optimal acid extraction process of dietary fiber. Under the optimum conditions of acid extraction, based on single factor of alkali extraction test, by using alkali extraction water/solid ratio, alkali extraction time, alkali extraction temperature and alkali extraction pH as response factors, and the extraction content of dietary fiber frombean dregs as response value, response surface method was used to obtain the optimal alkali extraction process of dietary fiber from bean dregs.【Result】The optimal acid extraction conditions of dietary fiber from Sandouyin soybean dregs were: the water/solid ratio of 1∶25, acid extraction time of 2.8 h, acid extraction temperature of 87℃ and acid extraction pH of 4.6. After acid extraction, the content of dietary fiber was 59%，which increased by 14.4% compared with that of raw bean dregs. The optimal alkali extraction conditions of dietary fiber from Sandouyin soybean dregs were: the water/solid ratio of 1∶35, alkali extraction time of 4h, alkali extraction temperature of 56℃ and alkali extraction pH of 11.8. After alkali extraction, the content of dietary fiber was 75.7%, which increased by 30.1% compared with that of raw bean dregs.【Conclusion】In verification process of three batches, the measured values of dietary fiber contents in bean dregs were basically similar with the predicted values, the process in this experiment was stable and feasible, which was of great significance to the recycling of Sandouyin soybean dregs.