Dissertation > Industrial Technology > Light industry,handicrafts > Food Industry > Beverage cold manufacturing industry > Tea > Product standards and testing

Development of Detection Methods of Effective Biological Components from Tea by High Performance Liquid Chromatography and Their Applications in the Analysis of Fenghuang Oolong Tea

Author WangLin
Tutor ZengXiaoXiong
School Nanjing Agricultural College
Course Of Food Science
Keywords HPLC methylated-catechins Toyopearl HW-40S SPE Fenghuang Oolong Tea
CLC TS272.7
Type Master's thesis
Year 2010
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For thousands of years, tea is one of the most popular drinks in the world. There are various components which have benefits for people’s health in the tea, such as polyphenols, amino acids, and purine alkaloids. A lot of biological functions, such as anti-oxidation, anti-cancer and anti-allergy, have been attributed to the presence of the effective biological components from tea. Therefore, the development of these components’ determination, which are fast, high-effective and accurate, has been studied a lot.Recently, Fenghuang Oolong Tea, which is only produced in Fenghuang Tawn, Chao An Country, Guang Dong Province, China, has gained several domestic researchers’ interest, for whose aroma is similar to the aroma of natural flowers and taste is very special. Now, the study of Fenghuang Oolong Tea are focusing on the formation of the special aroma、the function of anti-oxidation and the management of the produce, however, the systemic determination of the major effective biological components in Fenghuang Oolong Tea has not been reported yet.Therefore, in this study, a high performance liquid chromatography(HPLC) method which could detect ten different kinds of catechins, gallic acid, theobromine, caffeine and theophylline in 15mins, had been developed; and a HPLC method of detecting 17 different kinds of free amino acids in the tea had also been built. At the meantime, the two developed methods had been used in the determinations of Fenghuang Oolong Tea. Major research results were followed: 1. On the basis of purchased catechins standars and Japanese Benifuji Tea which with high content of methylated-catechins, the catechins extraction from Benifuji Tea which was concentrated by HP-20 resin, was separated by medium-pressure Toyopearl HW-40S column which was eluted by 80% ethanol. Then, the different fractions were collected and separated by the same conditions, respectively. Two kinds of methylated-catechins EGCG3"Me and ECG3’Me with the concentrations of 98.4% and 95.3%, whose structures have been identified by the results of the analysis of 1H NMR、ESI-TOF-MS and the data in the references, have been gained, as well as catechins EC, EGC, ECG and EGCG, whose purity were all above 97%.2. Epimers of EC, EGC, EGCG and ECG with higher concentration which were prepared before, were heat-isomerizated and separated by a semi-preparative HPLC column Zorbax SB-C18 and an AKTA purifier, respectively. Epimers of C、GC、GCG and CG whose purity were all 98% were gained, and their structures have all been identified by the data of the results of 1H NMR. ESI-TOF-MS.3. By using precolumn derivatization with o-phthaladehyde combined with HPLC, the methods of determination and quantitation of 17 kinds of free amino acids have been developed;with the treatment of SPE(solid-phase extraction) of the tea infusions, the phenolic compounds in tea infusion have been absorbed and the influences of the separation and determination of free amino acids were removed;the experiments have been designed to demonstrated the feasibility and effectivity of the treatment of SPE.4. Using the HPLC methods which have been developed,11 kinds of Fenghuang Oolong Tea were detected and the contents of ten different kinds of catechins, gallic acid, theobromine, caffeine and theophylline have been quantitated. The data showed that the content of gallic acid, theobromine and theophylline were pretty low when caffeine was much higher, which was related to the growing environment of Fenghuang Oolong Tea; the content of ester-catechins in Fenghuang Oolong Tea was very high, which showed the forming conditions of the excellent quality of this kind of tea; after the treatment of SPE,17 kinds of free amino acids in the tea infusion were determined and quantitated by using precolumn derivatization with o-phthaladehyde combined with HPLC. The results illustrated that the total contents of the amino acids in the tea infusions, the concentrations and kinds of amino acids in different infusions were various, but Asp, Glu, Ser and Thea were the major amino acids in all infusions.

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