Optimization of ultrasonic-composite enzyme extraction of rubusoside from Rubus suabissimus by orthogonal design

Orthogonal design was used to optimize the extraction process of rubusoside from Rubus suabissimus S.Lee. On the basis of single-factor test, the factors ( solid-liquid ratio, ethanol concentration, ultrasonic power, p H) and levels were selected.According to the orthogonal design principle and analysis method, the optimum conditions were 2.6% of complex enzyme ( cellulase∶ pectinase and∶ papain = 1∶ 1∶ 1) concentration, 4.0 of p H value, 1∶ 20 of solid-liquid ratio, 40% of concentration of ethanol, 50 W of ultrasonic power, 40 of mesh sieves, 30 min of enzyme hydrolysis, 45 ℃ of extract temperature, 30 min of ultrasonic extraction time, 2 times of repeated extraction.Under the optimal extraction conditions, the rate of rubusoside was66.4% ± 0.9% and the content was 110.7 mg/g.