Retraction Note: Extraction of flavonoids and kinetics of purification by macroporous resins from quinoa

This paper systematically studied the extraction process of total flavonoids from quinoa and the kinetics of macroporous resin purification. On the basis of single-factor experiments, the optimum extraction and purification process of total flavonoids from quinoa was studied by orthogonal experiments. The results showed that the optimum extraction conditions were as follows: ultrasonic time 25 min, temperature 200 °F, solid-liquid ratio 1:10 (g/mL), reflux time 2 h, and ethanol concentration 90%. Under this condition, the total flavonoids extracted from quinoa was 3.859 mg/g. Fifteen percent NaCl was added to salt out protein from flavonoid solution. The best macroporous resin purification process was as follows: pH 2, flow rate 2 BV/h, 0.3 mg/mL flavonoid solution loading, 8 BV water wash with acetone elution. Under this condition, the adsorption rate of purified flavonoids was 80.89%. The purity can be increased from 7.09% of the initial extract to 28.48%.