Extraction of total dietary fiber from Sauropus androgynus L. Merr by ultrasonic-assisted enzymatic-gravimetric method

ObjectiveThe extraction process of total dietary fiber from Sauropus androgynus L. Merr by ultrasonic-as-sisted enzymetic-gravimetric method was optimized, in order to provide a theoretical reference for researching dietary fiber of wild vegetable. MethodUsing S. androgynus L. Merr as materials, the effects of protease types, enzyme amount, so-lution pH, ultrasonic time and ultrasonic temperature on extraction rate of total dietary fiber from S. androgynus L. Merr were investigated by single-factor test. Meanwhile, based on the results of single-factor test, the extraction technology was optimized using orthogonal experiment. ResultEffects of protease types on extraction efficiency were ranked as follows:papain>neutral protease>alkaline protease>trypsin. The optimal technological parameters for ultrasound-assisted enzyma-tic-gravimetric extraction of S. androgynus L. Merr total dietary fiber were as follows: papain amount 0.60% , solution pH 5.0, ultrasonic time 50 min and ultrasonic temperature 65 ℃. Extraction efficiency was effected by papain>ultrasonic time>ultrasonic temperature>solution pH. Under the above optimum conditions, the extraction rate of total dietary fiber from S. androgynus L. Merr reached up to 45.0%, which was close to the value(44.8%) of GB 5009.88-2014 Measure-ment of Dietary Fiber in Food. The coefficient of variation was less than 5.00%. ConclusionThe optimized extraction process by ultrasonic-assisted enzymetic-gravimetric method shortens enzymolysis time, and is easy to operate, hence it can be applied in scale extraction of total dietary fiber from samples.