Extraction of polyphenol from burdocks of color protecting and extraction conditions optimization

Color protecting processing in the pretreatment of burdock was studied to enhance polyphenols extraction. Extraction technological parameters including extraction time,ethanol concentration,extraction temperature,and solid-liquid ratio were optimized with orthogonal experiment.The results showed that VCwas the suitable color protection agent.At the concentration of 0.75%,the pretreatment of VCcould improve the extraction rate of burdock polyphenol.The result also showed that the optimal extraction condition were as following: solid-liquid ratio of 1∶ 9,extraction temperature of 75 ℃,extraction time of 65 min,ethanol solvent concentration of 65%.Under the optimal conditions,the extraction rate of polyphenols reached 7.12%.