Optimization and contrast of traditional and microwave brewing processes for tartary buckwheat tea by response surface methodology

Traditional and microwave brewing processes for tartary buckwheat tea were optimized by Response surface methodology(RSM)in this paper. The single and interactive effects of solid-liquid ratio,brewing temperature and time on the total flavonoid yield were researched in the traditional brewing process,the single and interactive effects of solid-liquid ratio,microwave time and microwave power on the total flavonoid yield were investigated in the microwave brewing process. By using the total flavonoid yield as the response value,the multiple response model was obtained by fitting the experimental results. In traditional brewing process:the maximum total flavonoid yield of 0.0350%±0.003% was obtained under the tea weater ratio was 2.00:100 (g:mL),brewing temperature was 100℃ and brewing time was 45 min,the absolut error between experimenal and theoretical values of 0.0357% was-0.0007%. In microwave brewing process:the maximum total flavonoid yield of 0.387%±0.003% was measured under the tea weater ratio was 2.00:100 (g:mL),microwave time was 170 s and microwave power was 400 W,the absolut error between experimenal and theoretical values of 0.393% was -0.006%. The experimental total flavonoids yields was both consistent well with the theoretical fitting values based on the multiple response models,the total flavonoid yield was increased by nearly ten times in microwave brewing process.