Optimization of Extraction Process of Tea Polyphenols by Internal Boiling Method and Comparison with Water Extraction Method

The extraction of tea polyphenols by inner ebullition was applied.To study the effect on extraction yield of tea polyphenols,the six factors of concentration of desorption agent(ethyl alaohol),the time of desorption,solid-liquid ratio of desorbent,the dosage of the extract(hot water),extraction time and extraction temperature were assayed.Based on single factor experiment,orthogonal test was designed to optimize extraction conditions of tea polyphenols. Compared with water extraction method,the effects of two processes on catechin components and antioxidant activities were investigated. A maximum extraction yield of tea polyphenols of 22.45%±0.11% was obtained under the optimized conditions:Concentration of desorption agent 50% ethanol solution;the time of desorption at room temperature 10 min;solid-liquid ratio of desorbent 1:6 g/mL;the dosage of the extract 1:110 g/mL;extraction time 10 min;the extraction temperature 100℃.Compared with water bath extraction,the extraction yield of tea polyphenols was increased by 11.53%,the high temperature extraction time was reduced by nearly 80%,the destruction of high temperature on the activity of tea polyphenols was avoided,more epicatechins were remained and antioxidant activities of tea polyphenols were strengthened significantly(P<0.05). Inner ebullition is an economical,rapid and effective method,which shows a very promising prospect for industrial applications in the extraction of tea polyphenols.