Journal of Tea Science

Condition Analysis and Numerical Simulation of Tea Plane Circular Sieve

ZHAO Zhangfeng, ZHANG Libin, WANG Xiaohua, ZHANG Xian, GAN Jianren

Journal of Tea Science. 2014, 34(1): 1-8. doi:10.13305/j.cnki.jts.2014.01.001

Abstract ( 427 )

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Tea plane circular sieve is one of the most important machines in tea sieving, it sieves the tea according to the size. The effect of sieving showed a great impact on the quality of the tea and the efficiency of tea processing. Based on the analysis on the motion path and sieve condition and sieving process of tea particles on the sieve surface was simulated by using discrete element analysis software PFC3D. Theoretical analysis and simulation results showed that: (1) the sieve permeation rate is related to tea motion path, relative radius vector of the sieve and the relative velocity, (2) there are different optimal circular speeds for different sieve mesh, (3) the sieve permeation rate can be improved and the motion path length of tea particles could be prolonged by increasing the radius of circle. The theory based on a single grain of tea is consistent with numerical simulation results of tea particles. It illustrated this theoretical analysis was suitable for tea particles sieving. The presented results provide the reference basis for the design and exploitation of tea plane circular sieve.

Effects of Baking Temperature on Quality and Chemical Components of Jiulongpao Oolong Tea

ZHONG Qiusheng, LIN Zhenghe, CHEN Changsong, CHEN Zhihui, YOU Xiaomei, CHEN Rongbing

Journal of Tea Science. 2014, 34(1): 9-12. doi:10.13305/j.cnki.jts.2014.01.002

Abstract ( 646 )

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In order to investigate the optimum baking temperature for granular shaped oolong tea processing, final firing tea was used to bake at 120℃, 100℃and 80℃, respectively. By sensory evaluation, we found that the score of Jiulongpao Oolong teas with 80℃baking temperatures were higer than other Jiulongpao oolong teas. The quality of Jiulongpao Oolong tea baked with 80℃ temperature was the best. Chemical analysis indicated that the contents of the major biochemical components of oolong tea, such as tea polyphenols, the water extract and the amino acid decreased with the increase of baking temperature, but the contents of caffeine, the total catechins and the flavonoid constituents revealed no significant differences. The contents of L-Theanine, Aspartic aicd, Serine, Glutamic acid were decreased while the content of EGC and C were increased with the raise of baking temperature. The aroma constituents of Jiulongpao Oolong tea with different baking temperature treatment were determined by HS-SPME/GC-MS.The content of alcohols, esters, ketones and nitrogenous compounds were decreased but the alkane and the vinyl compounds were increased. Concentration of aromatic constituents with aroma of flowers such as linalool, linalool oxides, nerolidol, hexanoic acid, 3-hexenyl ester, (Z)-butanoic acid, 2-methyl-, hexyl ester, β-phenylethyl butyrate, benzoic acid, hexyl ester, methyl jasmonate, hexanoic acid, hexyl ester, α-Jonone, 5,9-Undecadien-2-one,6,10-dimethyl-, cis-Jasmone, indole decreased. The Hydrocarbon compounds such as β-Myrcene, Limonene, 5-Methylenecycloocta- 1,3-diene, β-sesquiphellandrene, 2,4,6-Trimethyl-1,3,6-heptatriene, dodecane and the nitrogenous compounds such as benzyl nitrile increased distinctively.

Study on Fermentation Technology of Tea Wine with Guava Juice

LIU Mengjia, ZHOU Qiang, CHEN Shudi

Journal of Tea Science. 2014, 34(1): 21-28. doi:10.13305/j.cnki.jts.2014.01.003

Abstract ( 517 )

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Using tea from Minnan district as the main raw material, the optimum processing parameters of fermented tea wine mixed with guava juice were investigated. The optimum fermentation conditions were obtained by means of the single factor analysis, orthogonal experiment method and experimental validation. The optimum processing parameters are as follows: the ratio of tea and water is 1:110, the ratio of tea liquor and guava juice is 2:1, initial soluble solid content is 20°Bx, inoculation quantity is 7%, the tea wine is fermented with Lapsang souchong and fruit yeasts RW. The final product showed shallow light red color, harmonious flavor, mellow taste and unique aroma of tea and guava.

Effect of Raw Tea Processing with Different Rolling Technology on the Quality of Green Tea Beverage

YUAN Haibo, YIN Junfeng, DENG Yuliang, XU Yongquan, WANG Fang, CHEN Gensheng

Journal of Tea Science. 2014, 34(1): 29-35. doi:10.13305/j.cnki.jts.2014.01.004

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Different raw teas made from tea var. Fuding Dabai with different rolling technology were adapted to process green tea beverage and the leaching characteristics and quality stability were studied. Results showed that, the treatment of rolling with hot air of 50℃ indicated good leaching characteristics, extraction of 10 min tea polyphenols leaching amount is about 92.9% at 60 min. Storage at 37℃ and 4℃ for 7 days, the treatment of rolling with hot air of 50℃ and rolling with fixation leaf while hot had a high value of total amino acids, the color value (L, –a/b) and sensory quality scoring in 4 kinds of rolling processing treatments, and showed good quality stability. Total content of ester catechins include EGCG, GCG, ECG, CG was relatively low after sterilization with the treatment of rolling with hot air of 50℃ and rolling with fixation leaf while hot. Comprehensive analysis, the processing technology of special ingredients of tea beverage should adopt heat-rolling technology for example roll with hot air of 50℃.

Cloning and Functional Verification of Two MYB Transcription Factors in Tea Plant [Camellia sinensis (L.) ]

GONG Niandi, GUO Lili, WANG Hongxue, ZHAO Lei, WANG Jie, WANG Wenzhao, LIU Yajun, WANG Yunsheng, GAO Liping, XIA Tao

Journal of Tea Science. 2014, 34(1): 36-44. doi:10.13305/j.cnki.jts.2014.01.005

Abstract ( 532 )

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R2R3-MYB in Sg4 subgroup probably participated in the regulation of lignin biosynthesis, which possibly play an important physiological role in plant growth and development. Two MYB transcription factors CsMYB4-5 and CsMYB4-6 in Sg4 subgroup were cloned by RACE technology. Investigation showed that the amino acid sequence of CsMYB4-5 showed 48.45% identity to AmMYB330 from Antirrhinum majus and 44.79% to AtMYB3 from Arabidopsis thaliana, while CsMYB4-6 showed 69.80% identity to AmMYB308 from Antirrhinum majus and 62.41% to AtMYB4 from Arabidopsis thaliana by bioinformatics analysis. The result of real-time fluorescent quantitative PCR showed that these two genes had all high expression levels in root while low expression levels in stem. The analysis of prokaryotic expression revealed that the recombinant CsMYB4-5 and CsMYB4-6 were expressed with a molecular weight of about 32 kD and 27 kD respectively. Compared with wild tobacco, transgenic tobacco with CsMYB4-6 gene appeared following symptoms: the veins of leaf tighten, lamina surface between veins with sags and crests, with white freckles in old leaf, but in transgenic tobacco with CsMYB4-5 gene the elder leaves turned yellow.

Analysis on Characteristic Flavor Components of Aged Pu-erh Tea

CHEN Meichun, CHEN Zheng, SHI Huai, LIU Bo, PAN Zhizhen, ZHU Yujing

Journal of Tea Science. 2014, 34(1): 45-54. doi:10.13305/j.cnki.jts.2014.01.006

Abstract ( 568 )

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Volatile compounds of aged Pu-erh tea were analyzed by solid-phase micro-extraction (SPME) combined with gas chromatography-mass spectrometry (GC-MS). Alkanes were the most abundant volatile components in aged Pu-erh tea, however, it contributes scarcely to the aroma of tea. Aromatic hydrocarbons and their derivatives and terpenes were two major aromatic groups characterized, then the esters and their derivatives. Aromatic hydrocarbons and their derivatives are mainly consisted of 1,1'-Biphenyl, 2,2',5,5'-tetramethyl- and Naphthalene, 1,2,3-trimethyl- 4-propenyl-, (E)-, terpene compound are mainly consisted of α-cedrene and longifolene, and the relative content of α-cedrene was selected as the index for analyzing aged Pu-erh tea. The content of the key constituents of age-aroma, 1,2,3-Trimethoxybenzene was increased with the raise of temperature, and the highest relative abundance of 1,2,3-Trimethoxybenzene is about 1.73%. The contents of polyphenols, total flavonoids, total soluble saccharide and free amino acid were 50.87, 11.7, 5.09 and 1.69 mg·g^-1, respectively, which were measured by colorimetric method.

Investigation on the Contrast Analysis on the Sensory Quality of Common Green Tea from Different Producing Areas

WEI Mingxiang, ZHANG Yingbin, TANG Desong, GONG Shuying, SHI Mengnang, YANG Jie, GU Zhilei

Journal of Tea Science. 2014, 34(1): 55-62. doi:10.13305/j.cnki.jts.2014.01.007

Abstract ( 426 )

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Green tea is produced almost all the tea-producing regions in China. A survey was performed to compare the sensory quality of common green tea from different tea-producing areas. A total of 287 green tea samples were collected and their sensory characteristics were evaluated by panels. Results indicated that a certain degree of positive correlation existed between green tea price and sensory quality. Sensory quality of green teas was significant different between different producing areas. The results provided the support for the improving the overall quality of common green tea in China.

Discriminant Analysis of Tea Category Based on Fourier Infrared Spectra

WU Quanjin, DONG Qinghua, SUN Weijiang

Journal of Tea Science. 2014, 34(1): 63-70. doi:10.13305/j.cnki.jts.2014.01.008

Abstract ( 509 )

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The discrimination of tea category based on FTIR and stepwise discriminant analysis was studied, using the synchronous modeling and specific tea modeling with Oolong tea, green tea, black tea and white tea as the samples. The results showed that the recognition accuracy of the resubstitution and external validation of tea category using synchronous modeling based on absorption values at 1 000~1 800 cm^-1 band, the absorption ratio in the main peak, the extracted modeling factors of the former two were 84.8% and 85.0%, 81.9% and 80.0%, 89.0% and 88.5% respectively. The recognition accuracy of the resubstitution and external validation of tea category using specific tea modeling based on the three methods were 94.2% and 95.0%, 89.2% and 90.0%, 93.0% and 95.0% respectively, and 4 discriminant functions of synchronous analysis and specific tea analysis which can discriminate these four kinds of tea effectively were established respectively. The results also indicated that the effect of tea-specific modeling was better than synchronous modeling.

Study on Fingerprint on Volatile Constituents of Pu-erh Tea

LV Haipeng, ZHONG Qiusheng, SHI Jiang, ZHANG Yue, LIN Zhi

Journal of Tea Science. 2014, 34(1): 71-78. doi:10.13305/j.cnki.jts.2014.01.009

Abstract ( 453 )

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The fingerprint on volatile constituents of Pu-erh tea was investigated using HS-SPME/GC-MS. Results showed that the volatile constituents of Pu-erh tea can be well separated using HS-SPME/GC-MS. Based on the analysis of GC chromatogram of 17 tea samples collected from Yunnan province, it was confirmed that 26 peaks in chromatograms can be selected as the fingerprint of peaks of volatile constituents, and it was established as the fingerprint chromatogram for Pu-erh tea. Moreover, the GC fingerprints were analyzed by similarity analysis. The method is of high degree of reproducibility and the resolving of each component is satisfactory, thus the established fingerprints could be used as one of the aroma quality control index for identification and quality assessment of Pu-erh tea.

Tannase Production from Tea Stalks under Non-heat-treated Solid State Fermentation

WU Changzheng, CAI Huinong, NI Hui, ZHU Yanbing, YANG Yuanfan, XIAO Anfeng

Journal of Tea Science. 2014, 34(1): 79-86. doi:10.13305/j.cnki.jts.2014.01.010

Abstract ( 555 )

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The tannase production from Aspergillus niger by non-heat-treated solid state fermentation were investigated using tea stalks as substrate. The results showed that non-heat-treated solid state fermentation stimulated the production of tannase by 3.2-fold, when compared to that of heat-treated group. Supplementation with tannic acid was confirmed to have no influence on tannase production. Meanwhile, additional inorganic salts, carbon and nitrogen sources showed synergistic effect on tannase formation. Sucrose supplementation obtained maximum tannase yield, but the enzyme productivity in the initial stage of fermentation was decreased. Additional ammonium chloride played an important role in tannase synthesis process. It not only increased tannase production, but also shortened the fermentation period observably. Moreover, being supplemented with 7% sucrose and ammonium chloride obtained highest tannase production (23.6 U·g^-1). These results demonstrated that using tea stalks as substrate to produce tannase by non-heat-treated solid state fermentation is a good choice, which can provide the theory basis for further study of tannase production. Meanwhile, it will help to promote the large-scale exploitation of tea stalks and to increase the economic value of this agro-residue.

Effects of Exogenous Spermidine on Growth of Tea Plant under Lead Stress

SHEN Lu, XIAO Bin, ZHOU Xuan, ZHAO Jiuzhou, JIN Yuan

Journal of Tea Science. 2014, 34(1): 87-94. doi:10.13305/j.cnki.jts.2014.01.011

Abstract ( 420 )

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By adopting the pot experiment and using Longjing 43 cultivar as test material, the effects of 1.0 mmol·L^-1 exogenous spermidine on the growth of tea plant, and the physiological indexes in leaves such as the activity of leaf antioxidant enzymes, osmotic adjustment substances content, MDA content, cell membrane permeability and chlorophyll content were investigated under different concentration lead stress. The results showed that: low concentration of lead stress could promote the growth of tea plant, while high concentration of lead stress influence the growth of tea plant. Applying exogenous spermidine could effectively mitigate the damage of tea plant caused by increase of lead stress, promote the growth of tea plant, improve the activity of antioxidative enzyme, soluble protein content, chlorophyll content, and reduced the proline content, MDA content and the relative conductivity, so to promote the growth of tea plant. It suggested that 1.0 mmol·L^-1 exogenous spermidine has a positive role in promoting the growth of tea plant under lead stress.

Identification and Phylogenetic Analysis of Anthracnose Pathogen Colletotrichum fructicola Isolated from Camellia sinensis

LIU Wei, YE Naixing, CHEN Yusen, LIAN Lingli, LIU Wei, JIN Shan, LAI Jiandong, XIE Yunhai

Journal of Tea Science. 2014, 34(1): 95-104. doi:10.13305/j.cnki.jts.2014.01.012

Abstract ( 675 )

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Eight strains of anthracnose pathogen, ZHG, WSX, ZTG, WHG, FTG, AHD, WRG and SLH were isolated from different tea cultivars in Fujian Province. These strains were identified by using morphological method and rDNA-ITS sequence analysis. The results showed that SLH strain was identified as Colletotrichum gloeosporioides, while the other seven strains were Colletotrichum fructicola, which has never been discovered on tea plant. The ITS sequences of C. fructicola and those of nine strains of anthracnose pathogen from tea-oil tree, jasmine plant and papaya (psidium guajave), were got for a clustering analysis. The results showed that base mutations or deletions were existed in the seven strains from tea plant, and the seven strains of C. fructicola were geneticly close to the pathogen C. gloeosporioides, isolated from tea plant, oil-tea plant and jasmine plant.

Reclusion: Cultural Identity of Tea Dringking in the Tang Dynasty

GUAN Jianping

Journal of Tea Science. 2014, 34(1): 105-110. doi:10.13305/j.cnki.jts.2014.01.013

Abstract ( 567 )

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Cultural identity refers to the essential character of an ethnic group’s culture, which never stop creating and changing. Since tea has been widely accepted by different classes of society from various ethnic around the world, tea culture is abundant with diversity. As history tells us, the development of tea culture has been in maturity since the Tang Dynasty, which defined a time period, as well as an identity of major ethnic in China. This paper takes the Tea Saint Lu Yu, the founder of Chinese classic tea study, as a symbol for time division. By reviewing literature from the Tang Dynasty, it explains the reclusion as a cultural identity of drinking tea lifestyle in that period. That not only delivers a qualitative analysis for tea culture particularly in Tang Dynasty, but also lays a basic foundation for the study on relationship between Lu Yu and the tea. With this application of cultural identity theory, it involves the study on tea into the context of cultural research, thus to promote the study on tea culture in a more academic and professional way.

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