People’s interest in green tea powder is increasing currently. The addition of green tea powder to food products could increase antioxidant activity and other health benefits. GMB 7 and GMB 9 are local tea clones of the Assam variety widely planted in Indonesia’s tea plantation. This study aimed to determine green tea powder’s total polyphenols and antioxidant activity from local tea clones (GMB 7 and GMB 9). Total polyphenol and antioxidant activity were determined by Folin-Ciocalteau and free radical of DPPH methods, respectively. Our results showed that the total polyphenols of green tea powder were 27.61% and 27.31% for the GMB 7 and GMB 9 clones, respectively. Furthermore, the antioxidant activity of green tea powder with IC50 was 15.41 mg/L and 17.32 mg/L for clones GMB 7 and GMB 9, respectively. The results indicate the potential for the development and utilization of local clones to fulfill domestic green tea powder production. Further research is needed to determine the health benefits of green tea powder from clones of The Assam varieties.
White tea is produced from the bud of Camellia sinensis, which is processed with minimum processing. Withering is an important step in processing white tea. Withering in white tea processing utilizes sunlight to obtain moisture content properly. This study aims to determine the chemical changes of tea buds during the processing of white tea. Observations were carried out on the withering of 4, 21, 45, 69 and 93 hours. The parameters observed included total polyphenols, theaflavin, and thearubigin. The results showed that during the process of withering changes in total polyphenols, from 33% at 4 hours of withering, to 28% at 93 hours of withering. Theaflavin content decreases from 0.05% to 0.036% at 4 hours to 96 hours withering, respectively. This shows that enzymatic oxidation reactions still occur during the processing of white tea. Results suggest that withering for 96 hours on the processing of white tea is optimum. The present study also provides guidelines on application processing to produce a high quality of white tea.
European markets have implemented the Commission Regulation (EU) Number 1146/2014 of 23 October 2014 of the MRL for Anthraquinone (9,10-AQ) is 0.02 ppm. After this implementation for 9,10-AQ for tea in the European market, there has been a decreased by 33.6% in Indonesian tea exports. This paper will explain the preliminary study results of 9,10-AQ in Indonesian tea that consist of (1) the results of 9.10- AQ content of Indonesian tea samples, (2) 9,10-AQ content on fresh tea shoot and in each stage of tea processing, (3) the content of 9.10-AQ in tea liquor, and (4) results of antioxidant activity analysis of Indonesian tea in free radical scavenging by DPPH analysis (1,1-diphenyl-2-picrylhidrazyl). Samples selection selected from West Java and East Java as center of tea producing province in Indonesia with incidence of high 9,10-AQ levels in tea. The results show that the 9,10-AQ content depend on drying system technologies. The data conclude that 9,10-AQ level increase due to withering process by 0.004 ppm and in drying process it increase higher (0.007 ppm). The data of 9,10-AQ level of tea liquor are all below the MRL, therefore brewed tea is safe for health. Antioxidant activity of Indonesian tea with 9,10-AQ level above the MRL (0.043 ppm) is very strong that very potential to reduce the negative effects of tea contaminants by free radicals scavenging.
Keywords: Antraquinone, Maximum Residue Level (MRL), Preliminary Study Results, Indonesian Tea, European Market
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