Studies on Extraction Technologies of Tea Polyphenols from Different Types of Tea

Selecting the black tea and green tea leaves as the raw materials,the extraction techniques of tea polyphenols were investigated in the high-grade tea named as Puer.In the study,ethanol was used as the solvent,and the four factors: extraction temperature,ratio of solid-to-liquid,extraction time and the solvent concentration were selected at three levels to investigate the influences on the extraction of tea polyphenols.The results show that the optimum techniques of the black tea were that the extraction temperature was 50 ℃,the extraction time was 30 min,the ratio of solid-to-liquid was 1∶80,the extraction ethanol concentration was 60% and thus the ratio of the extraction was 20.35%.The optimum techniques of the green tea were that the extraction temperature was 50 ℃,the extraction time was 40 min,the extraction ethanol concentration was 50%,the ratio of solid-to-liquid was 1∶80,and thus the ratio of the extraction was 25.44%.