Optimization of ultrasonic-assisted extraction of red pigment from jujube peel by response surface methodology

The Ultrasonic-assisted extraction condition of red pigment from jujube peel was optimized by using response surface method. Based on single factor experiments, a four-factor-three-level experiment design were developed by box-benhnken central composite design method with the causal factors of ultrasonic time, ultrasonic power, concentration of NaOH, ratio of raw material to liquid and the extract absorbance value for the response, and the response surface methodology ( RSM) was applied to optimize the ultrasonic-assisted extraction. The optimum ultrasonic-assisted extraction conditions were as follow:ultrasonic time was 30min, ultrasonic power was 80W, concentration of NaOH was 0.5mol/L and the ratio of raw material to liquid was1∶10g/mL (w/v) . Under the optimum extraction technology condition, the absorbance value predicted of the model was 1.445 and the experimented value was 1.427. The model had a good degree of fitting, so it could be used to describe the test result preferably.