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Zhao Y.,Yunnan University | Ye M.,Yunnan Agricultural University | Fan L.M.,Yunnan Agricultural University | Zha Y.G.,Yunnan Agricultural University | Gao X.Y.,Puer Tea Research Institute
Advanced Materials Research | Year: 2013

Some chemical compounds in low polar fractions of Mikania micrantha H.B.K. extracts can strongly influence seeds germination and seedling growth of Raphanus sativus. In this study, we provide evidence that the chemical compounds in a low polar fraction chromatographed on normal phase silica gel columns from petroleum ether extract of M. micrantha have strong activity to inhibit the seeds germination and seedling growth of Raphanus sativus. Two main chemical constituents, α-Bisabolol and Eudesma-5,11(13)-dien-8,12-olide, in the active fraction were confirmed by GC-MS analysis. © (2013) Trans Tech Publications, Switzerland. Source


Chen H.,Beijing University of Chemical Technology | Li H.,Beijing University of Chemical Technology | Lu J.,Beijing University of Chemical Technology | Sheng J.,Puer Tea Research Institute | Sheng J.,Yunnan Agricultural University
Beijing Huagong Daxue Xuebao (Ziran Kexueban)/Journal of Beijing University of Chemical Technology (Natural Science Edition) | Year: 2013

High performance liquid chromatography (HPLC) has been employed for the determination of epigallocatechin gallate, epicatechin, theanine, quercetin, xanthine and hypoxanthine during the pile-fermentation of Pu'er tea. It was found that during the fermentation process, the content of epigallocatechin gallate, epicatechin, theanine and quercetin decreased continuously, whilst the content of xanthine and hypoxanthine increased. Correlation analysis has been established for the six compositions. A significant positive correlation was found between polyphenols and amino acids. Source


Li C.,Beijing University of Chemical Technology | Lv J.,Beijing University of Chemical Technology | Yang R.,Puer Tea Research Institute | Yan L.,Puer Tea Research Institute | And 5 more authors.
Beijing Huagong Daxue Xuebao (Ziran Kexueban)/Journal of Beijing University of Chemical Technology (Natural Science Edition) | Year: 2012

pH values of Pu'er tea samples were measured during the pile-fermentation process. The study found that during the fermentation, pH decreased to 4.5 at the beginning, stabilized in the mid-term and finally increased. According to the characteristics of high temperature and acidity, combining culture-independent with molecular biology methods allowed bacteria to be isolated and identified from all the tea samples at high temperatures. The results showed the presence of a large number of thermophilic bacteria including Bacillus coagulans, Bacillus subtilis, Bacillus licheniformis, Bacillus thermoamylovorans, Bacillus shackletonii, Geobacillus thermoleovorans, Pediococcus acidilactici and Lactobacillus plantarum. These thermophilic bacteria and thermophilic fungi play a key role in the fermentation of Pu'er tea. Source


Lu W.,Beijing University of Chemical Technology | Lu J.,Beijing University of Chemical Technology | Yan L.,Puer Tea Research Institute | Li H.,Beijing University of Chemical Technology | And 4 more authors.
Beijing Huagong Daxue Xuebao (Ziran Kexueban)/Journal of Beijing University of Chemical Technology (Natural Science Edition) | Year: 2013

The sources of the microorganisms involved in the fermentation of Pu'er tea and the presence, as well as the role, of these airborne microorganisms have been investigated. Airborne microorganisms in three tea gardens in the Tea Seed Manipulation Farm of Pu'er in Yunnan province were collected by an Anderson sampler and identified by molecular biology methods after being cultured. Sampling was carried out three times over three months. Microorganisms in the air were collected and cultured and isolated at two temperatures in order to identify them. The species of airborne microorganisms and their relative proportions in the Pu'er tea growing environment were obtained. The results lay the foundations of an understanding of the source of some of the microorganisms involved in the fermentation of Pu'er tea. Source

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