Optimization of ultrasonic-assisted extraction and spray drying of anthocyanins from purple corn cob

Response surface methodology was used to optimize the ultrasonic assisted extraction conditions of anthocyanin from purple corn cob and improve the extraction rate.Anthocyanin freeze-dried powder mixed with maltodextrin was processed into powder by spray drying method. The results showed that the optimum conditions were as follows: the solid-liquid ratio, extraction temperature, extraction time and ultrasonic time were 1 ∶ 13 ( g/m L) , 41 ℃, 31 min and 20 min, respectively. The anthocyanin content and the extraction yield were ( 4.623 ± 0.021) mg/g and 94.8% at this condition. The anthocuanin powder had low moisture 4.8% and embedding rate 86.7% when the inlet air temperature, the mass ratio ( anthocyanin∶ maltodextrin) and the solid concentration during spray-drying were 150 ℃, 1 ∶ 1 and 15%, respectively. The conditions of anthocyanin extraction from purple corn cob and anthocyanin powder preparation were optimized by the single factor experiment and the response surface methodology, and the results provided a reference for the development of purple corn cob.