Response surface optimization of ultrasonic-assisted extraction of yellow pigment from Buddleja officinalis Maxim

The ultrasonic-assisted extraction technology of yellow pigment from Buddleja officinalis Maxim. was optimized by using response surface methodology (RSM). The single factors tests and Box-Behnken experimental design were conducted and the optimal extraction conditions were determined as follows: ethanol concentration 68%, liquid/material ratio (mL/g) 50:1, ultrasonic power 499 W, extraction temperature 74°C, and extraction time 35 min. Under this optimal conditions, the theoretical absorbency of yellow pigment from Buddleja officinalis Maxim. can reach 0.540, while the experimental value is 0.538, with a relative stand error 0.37% to the theoretical value.