Journal of Tea Science

Review on Tea Sediment Formation and Its Controlling Methods

XU Yongquan, YIN Junfeng

Journal of Tea Science. 2016, 36(4): 337-346. doi:10.13305/j.cnki.jts.2016.04.001

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Sediment easily forms during the process and storage of tea beverage, instant tea powder and concentrated tea, which not only has an unattractive appearance, but also detracts from the flavor quality of tea products. However, there are no clear forming mechanism and controlling methods of tea sediment because the forming of tea sediment is rather complicated and lacks satisfactory solution. And at present, most of tea beverage producers remove tea sediment or inhibit tea sediment formation by physically removal or chemically de-creaming. These methods not only cause a great loss of active ingredients and decrease healthy functions, but also influence the appearance and inherent quality of the products, and then hinder the development of Chinese tea-beverage industry. Tea cream, the turbid phenomenon produces when tea infusion cools, is the previous process of tea sediment formation. It was reported that tea sediment can be divided into reversible and irreversible sediment. And their chemical constituents, formation mechanism and influencing factors were distinctly different. In order to effectively control the sediment in tea beverage, this paper summarizes the chemical components participating in tea sediment formation, the factors and the mechanism of tea sediment formation, and the controlling methods.

Effects of Catechins on Acute Hyperuricemia in Mice

JIN Hongna, SONG Yewei, CUI Weibo, XIE Hong

Journal of Tea Science. 2016, 36(4): 347-353. doi:10.13305/j.cnki.jts.2016.04.002

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The mouse model of acute hyperuricemia was established by using 300 mg·kg^-1 oxonic acid potassium salt to evaluate the influence of catechins on serum uric acid. The xanthine oxidase (XOD) activity in serum and liver and the inhibitory effect of catechins on XOD in vitro was further studied. Results showed that with dosage of 600 mg·kg^-1, EC, ECG and EGC reduced the serum uric acid level in vivo significantly by 23% (P<0.001), 35% (P<0.001) and 37% (P<0.001), respectively compared with the model group. ECG could reduce XOD activity in serum and liver approximately by 31% (P<0.01) and 32% (P<0.05). In vitro, ECG and EGCG could inhibit XOD activity. Therefore EC, ECG and EGC could reduce the level of uric acid of hyperuricemia mice. The mechanism of uric acid lowering effect of ECG might be associated with its inhibitory effect on XOD.

Effect of Green Tea Infusions on Obesity-associated Gut Microbiota

GUO Hongwen, XU Xiangyu, CHEN Yingjie, NI Li, LIU Zhibin

Journal of Tea Science. 2016, 36(4): 354-362. doi:10.13305/j.cnki.jts.2016.04.003

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In recent years, the effect of tea on intestinal microflora attracted widespread attention. In this study, the green tea infusion with human fecal was mixed, the change of intestinal flora related to obesity in different fermentation time points (0, 6, 12, 24 h) were measured and the role of tea regulated intestinal microflora was evaluated. The results showed that green tea infusion inhibited the reduction of total gut bacteria, Bacteroides and Firmicutes after fermentation for 24 h (P<0.05), improved the relative abundance of Bacteroides and Firmicutes, reduced the F/B ratio, which provides a reference to support the important role of green tea infusion in improving intestinal health, reducing weight and lowering blood lipid.

Inhibition of Theaflavins on Protein Carbonylation and Aggregation in the System of BSA/MDA Carbonyl-ammonia Cross Linking Reaction in vitro

ZHANG Jing, CAI Shuxian, HUANG Jian'an, LI Juan, ZHONG Ni, YANG Heng, LIU Zhonghua

Journal of Tea Science. 2016, 36(4): 363-371. doi:10.13305/j.cnki.jts.2016.04.004

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A model of age pigment generation was builted by carbonyl-ammonia cross linking reaction in vitro, the datas indicate that theaflavins can not only inhibit the generation of age pigment in protein carbonylation, but also supress β-sheet-rich in aggregate protein in this model by thioflavin T-based fluorometric assay, scanning electron microscope, transmission electric microscope, SDS-PAGE and NBT staining, there are postive relationship between protein carbonylation on mechanism of aging and protein aggregation that lead to neurodegenerative disease.

Effects of Different Fixatives on Fidelity and Slow-release of Huangjingui Tea Essential Oil Aroma

LIU Wanqiong1, ZHANG Yingbin2, GONG Shuying1*, CHEN Ping1, FAN Fangyuan1, YANG Mengxuan1, GU Zhaoqi1

Journal of Tea Science. 2016, 36(4): 372-378. doi:10.13305/j.cnki.jts.2016.04.005

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An optimized and improved SDE method was carried out to get tea essential oil of high fidelity and the optimum condition was 2 h extraction of 25 g tea by continuous hot flowing steam. The effects of fixatives (diethyl phthalate, benzyl benzoate and vanillin) on this tea essential oil and their roles on the performance of aroma slow-release in tea essential oil were also studied by GC/MS and olfactory evaluation. The results showed that the persistence of fragrance was improved by all 3 fixatives. Among these, tea essential oil with diethyl phthalate showed highest fidelity of original odor type, indicating diethyl phthalate could be applied to manufacture tea aroma standard reference. Vanillin showed the best performance for aroma slow-release but the lowest fidelity. Benzyl benzoate had excellent coordinate ability and showed good performance for both fidelity and persistence which can be applied to develop tea fragrances. This study provided new ideas for fidelity and slow-release of tea essential oil. Meanwhile, the theoretical and practical foundation was established for hypostatization of tea olfactory term and innovation of tea fragrance and other field of tea industry.

Identification of Spring Sun-dried Tea from Jingmai Area by HPLC Fingerprint

MA Cunqiang, ZHOU Binxing, YANG Chao, WANG Hongzhen, XU Zhengwen

Journal of Tea Science. 2016, 36(4): 379-388. doi:10.13305/j.cnki.jts.2016.04.006

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Using 80 spring sun-dried tea samples from Jingmai and Mangjing and different years as materials, standard chromatograms of Jingmai and Mangjing spring tea were constructed by HPLC fingerprint. There were 22 and 24 characteristic peaks in Jingmai and Mangjing standard chromatograms respectively, with 18 shared peaks. Jingmai and Mangjing spring sun-dried tea showed large differences in EGCG and ECG contents. Because of the uncertainty in pu-erh tea storage and the high similarity between Jingmai and Mangjing spring sun-dried tea, there might be some errors in cluster analysis of different years. For example, one of 20 tea samples can not be clustered successfully. Cluster analysis could successfully distinguish spring sun-dried teas from Jingmai area (including Jingmai spring tea and Mangjing spring tea) from other areas. Similarity analysis showed that the similarities between the standard chromatogram and tea samples from Jingmai and Mangjing were 98.9% and 99.2%, which were lower than 95% for tea samples from other areas. In conclusion, HPLC fingerprint was able to identify the sun-dried tea production areas in Jingmai of the same year, which provided a more scientific and complete method for the identification of sun-dried tea from different areas.

Ecological Effects of Intercropping Tea with Aromatic Plant Basil and Perill in Young Tea Plantation

ZHANG Zhengqun, TIAN Yueyue, GAO Shuwen, XU Yongyu, HUANG Xiaoqin, ZHANG Lixia

Journal of Tea Science. 2016, 36(4): 389-395. doi:10.13305/j.cnki.jts.2016.04.007

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To evaluate integrated ecological effects of intercropping young tea plants with aromatic plants, we investigated the populations of pests and natural enemies, soil nutrient status, growth of tea plants and tea ingredients in the intercropping plots. Aromatic plants intercropped with young tea plants reduced the numbers of Empoasca onukii Matsuda and Apolygus lucorum Meyer-Dür, and increased the numbers of natural enemies, such as coccinellids, lacewings, parasitoids and spiders in the tea plantations. The contents of ammonium nitrogen, available phosphate and available potassium in the soils in the plots intercropped with aromatic plants were relatively higher than those in the plots intercropped with white clover and the control. Intercropping facilitated tea growth, enhanced tree crown formation and increased vigor of young leaves, which are necessary for high yield of tea. Intercropping tea with aromatic plants decreased the contents of TP and caffeine, and increased the contents of soluble sugar and catechins in tea leaves, and finally improved the quality of tea. The results demonstrated that intercropping tea with aromatic plants is an effective cultivation method with great ecological economic benefits, and can promote the development of ecological tea plantation.

Research on Adsorption Characteristics of Tea Polysaccharides to Fluorine

GAO Huimin, ZHU Xiaojing, LI Panpan, NI Dejiang, CHEN Yuqiong

Journal of Tea Science. 2016, 36(4): 396-404. doi:10.13305/j.cnki.jts.2016.04.008

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The adsorption characteristics of tea polysaccharides (TPS) to fluorine under different temperatures and dose of fluoride was studied. The adsorption models were established and the structure and composition of TPS were analyzed. The results showed that the temperature was an important factor influencing fluorine adsorption of TPS. Loose surface structure was observed in TPS under 40℃ by SEM, which showed the strongest adsorption ability to fluorine. With the increase of temperature, the surface structure of TPS gradually became dense, while the adsorption ability to fluorine descended. However, the adsorption ability to fluorine increased after 70℃. The amount of fluorine absorption by TPS increased with the increasing of exposure amount of fluoride with its peak at 1.8 times of polysaccharide under 40℃. The adsorption behavior was in accordance with Langmuir model with the distribution factors (R_L) between 0 and 1 and belonged to a favorable adsorption. As proteins and pigments were removed,, structure and composition of crude polysaccharides changed greatly, with sharp decrease of F^-, Al³⁺, Fe³⁺ and Mn²⁺ contents and fluorine adsorption capacity. The results suggest that the characteristics of fluorine absorption is related to the composition and structure of polysaccharides. Proteins, Mn²⁺, Al³⁺ and Fe³⁺might also play important roles in it.

Cloning and Expression Analysis of Alanine Aminotransferase Gene in Camellia sinensis

BAI Peixian, WANG Liyuan, WEI Kang, RUAN Li, CHENG Hao, ZHANG Fen, ZHANG Chengcai

Journal of Tea Science. 2016, 36(4): 405-413. doi:10.13305/j.cnki.jts.2016.04.009

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Alanine Aminotransferase (AlaAT) is a critical enzyme involved in carbohydrate and nitrogen metabolisms. In this study, a cDNA (1 747 bp) with a complete ORF (1 626 bp) of AlaAT1 was isolated from tea plant (Camellia sinensis). The cDNA encodes a protein with 541 amino acids, which has a molecular mass of 59.4 kD and a theoretical isoelectric point (pI) of 5.82. The deduced sequence of protein CsAlaAT1 shared 84% similarity with AlaAT1 in Arabidopsis thaliana, which contains a highly-conserved pyridoxal 5′-phosphate binding site. Secondary structure prediction showed that the CsAlaAT1 was comprised of alpha helix (40.67%), random coil (29.57%), beta turn (13.68%) and extended strand (16.08%), localized in mitochondrion and had no signal peptide or transmembrane structure. The expression levels of CsAlaAT1 in various tissues and its responses to different N concentration were investigated by real-time fluorescent quantitative RT-PCR. The results of RT-PCR showed that CsAlaAT1 expressed in all tissues of tea plant and the highest transcript level was observed in roots. The transcript abundance of CsAlaAT1 was up-regulated by N in both shoots and mature leaves, especially under high N condition. Interestingly, the expression of CsAlaAT1 in roots was highly induced high N condition, but showed an opposite trend under low N treatment for 24 h.

Development of a CRISPR/Cas9 Constructed for Genome Editing of Caffeine Synthase in Camellia sinensis

TANG Yuwei, LIU Liping, WANG Ruoxian, CHEN Yuhong, LIU Zhonghua, LIU Shuoqian

Journal of Tea Science. 2016, 36(4): 414-426. doi:10.13305/j.cnki.jts.2016.04.010

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CRISPR/Cas9 technology (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) is a novel and powerful approach for targeted genome editing, such as targeted gene knock out or site-directed mutagenesis in a simple and easy way. Since its establishment, the CRISPR/Cas9 technique has been successfully applied in many eukaryotic organisms, including more than 10 plant species. However, it has not been available for genome editing of tea plant [Camellia sinensis (L.) O. Kuntze] due to the difficulty in constructing CRISPR/Cas9 expression vector. The present work developed an efficient method to construct a CRISPR/Cas9 expression vector for genome editing a tea caffeine synthase (TCS) by using general PCR, overlapping PCR and golden gate cloning technology. The present work would promote the application of CRISPR/Cas9 technology in genomic modification in tea plants.

First Discovery of Whitefly, Aleurocanthus inceratus Silvestri (Hemiptera: Aleyrodidae) on Tea Plants in China

WANG Jirui, MU Lixia, DU Yuzhou, XU Zhihong

Journal of Tea Science. 2016, 36(4): 427-431. doi:10.13305/j.cnki.jts.2016.04.011

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Aleurocanthus inceratus Silvestri, a newly recorded species of whitefly infesting tea plants, was morphologically described and illustrated. It has 11 pairs of spines along submarginal area, among which 5 pairs are on cephalothorax. Moreover, there are 9 pairs of spines on cephalothorax of the median dorsum, 14 pairs of spines on the median of venter, with 3 rows. Vasiform orifice and operculum are rounded.and cordate respectively., While caudal furrow is indistinct. Nine species of whitefly infesting tea plants in China were counted, namely, Aleurotrachelus camelliae (Kuwana), Parabamisia myricae (Kuwana), Aleurocanthus spiniferus (Quaintance), Aleuroclava guyavae (Takahashi), Aleurolobus rhododendri Takahashi, Dialeurodes citri (Ashmead), Aleurocanthus inceratus Silvestri. An identification key to identify these species based on the puparial characters was provided.

QTL Analysis for Anthracnose Resistance in Tea Plant (Camellia sinensis)

XU Liyi, TAN Liqiang, WANG Liyuan, QI Guinian, CHENG Hao, WEI Kang

Journal of Tea Science. 2016, 36(4): 432-439. doi:10.13305/j.cnki.jts.2016.04.012

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In order to provide a basis for breeding tea plants with anthracnose resistance, 170 F1 plants, derived from LJ43♀×BHZ♂, were used to constructed a linkage map by SSR markers. Field observation and indoor test were carried out in 2014. The data of phenotypic characters were used for QTL mapping and analysis by the method of MQM mapping. A pathogen was isolated from a diseased leaf of the F1 plants, and its gene sequence of ITS had 99% similarity with Colletotrichum sp. based on NCBI BLAST. The plants grown in open field were more easy to be infected by the pathogen than those grown in rooms. Eight QTLs were detected in six different linkage groups by QTL analysis. The LOD and PVE of individual QTLs ranged from 2.53 to 6.80 and 5.6% to 13.8%, respectively. A main QTL with LOD 6.80 and PVE 13.8% was detected in LG10.

Optimization Design of Tea Carding Machine Parameters Based on Genetic Algorithms

WANG Xiaoyong, LI Bing, ZENG Chen, LI Shangqing

Journal of Tea Science. 2016, 36(4): 440-444. doi:10.13305/j.cnki.jts.2016.04.013

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To reduce noise and vibration in working process, improve transmission performance of the machine and tea processing quality, genetic algorithms and Matlab toolbox were used to establish an optimal mathematical model of the planetary gear mechanism of the tea carding machine. The objective function and constraints were firstly set, the optimal parameters were calculated by matlab genetic algorithm toolbox and then verified by validation tests. The optimization results showed that the minimum transmission angle , working stroke , Polar angle were 71.1°, 122 mm and 3.6°, respectively. When tea carding machine was performed under optimal parameters, the noise decreased by 2 dB and the stripping tea rate increased by 2%. The study has significant importance for improving performance of tea carding machine and extending machine life.

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