Journal of Tea Science

Rewiew on Taste Characteristic of Catechins and Its Sensory Analysis Method

ZHANG Yingna, JI Weibin, XU Yongquan, YIN Junfeng

Journal of Tea Science. 2017, 37(1): 1-9.

Abstract ( 459 )

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Taste is the most important quality characteristics of tea infusion. Green tea taste is formed by the interaction of polyphenols, caffeine, amino acids, carbohydrates and metal ions. Polyphenols are the main taste substances of green tea infusion, with catechins as the major components of polyphenols. Catechins are the main contributors of the bitterness and astringency of green tea infusion. Varied intensities of bitterness and astringency of green tea infusions were caused by the different compositions and interactions of catechins. Sensory analysis by human is still the major method for the taste evaluation of tea infusion, which is irreplaceable nowadays. This paper reviewed the taste characteristics of catechins, interactions of taste substances, sensory-analysis method of taste substances, which aimed to improve the theory system of the taste characteristics of catechins and their interactions, and to lay the foundation for the use of sensory-analysis method in relative studies.

Research Progress of Black Tea on the Physiological Regulation and Disease Prevention in Gastrointestinal Tract

DU Yu, YUAN Haibo, CHEN Xiaoqiang, HU Ting, JIANG Yongwen

Journal of Tea Science. 2017, 37(1): 10-16.

Abstract ( 438 )

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Fresh leaves are processed into black tea by a series of enzymatic oxidation and other reactions. There are some distinctions in the flavor and functional chemicals between black tea and other tea. The black tea is endued with numerous health care functions by its chemical components, which play roles in the physiological regulation and illness prevention in gastrointestinal tract. The functional components in black tea can keep the intestinal flora balance by inhibiting the growth of harmful bacteria and promoting the growth of beneficial bacteria, protect the gastrointestinal mucosa by preventing oxidation of tissues, repairing oxidative damages and interaction with gastric mucus, glutathione and other substances. It can also adjust digestion and absorption by interaction with the enzyme digestion and promoting gastrointestinal peristasis, prevent gastrointestinal disease by interaction with the immune system regulatory factors, related transcription factors and enzymes. This paper reviews the recent advance in physiological regulation and disease prevention by black tea.

L-theanine Attenuates Tissue and Oxidative Damages in Heat Stressed Mice

GUO Chen, LIU Linfeng, XIANG Yi, LUO Li, LIN Ling, XIAO Wenjun

Journal of Tea Science. 2017, 37(1): 17-24.

Abstract ( 274 )

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The effects of different dosages of L-theanine on SPF grade Balb/KM male mice under heat treatment, including feed intake, weight, organs index, histopathological features of jejunum, activities of serum alanine aminotranferease (ALT) and aspartate aminotransferase (AST), contents of tumor necrosis factor (TNF-α), interleukin-6 (IL-6), interferon-γ (IFN-γ) in serum, content of liver homogenate malondialdehyde (MDA), activities of liver homogenate superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and histopathological features of liver tissue were studied. Results showed that pretreatment with different dosages of L-theanine increased the feed intake and body weight of the mice, enhanced the activities of liver homogenate SOD, CAT, GSH-Px, decreased the index of liver and spleen, damages in the jejunum, activities of serum ALT, AST, contents of TNF-α, IL-6 and IFN-γ in serum, content of liver homogenate MDA and attenuated the damages of liver by heat treatment. The best attenuating effect of L-theanine on damages was under middle dosage treatment. It suggests that L-theanine mainly improves the absorptive capacity, reduces the expressions of inflammatory cytokines and oxidative damage in mice, which finally attenuate the tissue and oxidative damages caused by heat stress.

Physicochemical Properties, in vitro Antioxidant Activities and Protective Effects of Liubao Tea Polysaccharides on HUVEC

YING Le, PAN Yue, WANG Yuefei, XU Ping

Journal of Tea Science. 2017, 37(1): 25-37.

Abstract ( 291 )

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Tea Polysaccharides were extracted and purified from Liubao tea. Three fractions of polysaccharides namely LTPS-30, LTPS-50 and LTPS-70 were then obtained from Liubao Tea Polysaccharides (LTPS) by 30%, 50% and 70% ethanol respectively. The main chemical compounds and monosaccharide compositions of these LTPS were investigated. The in vitro antioxidant activities of LTPS were determined by ABTS and FRAP assays. The potentially protective effects of LTPS on human umbilical vascular endothelial cells (HUVEC) were investigated according to the Na₂S₂O₃-induced model. The results showed that there were two main acidic polysaccharides in LTPS-70, LTPS-50 and LTPS-30. The order of molecular weight and total sugar content was LTPS-70<LTPS-50<LTPS-30. While the order of protein, polyphenol contents and antioxidant abilities determined by ABTS and FRAP assays showed the opposite trends. LTPS-70 exhibited the protective effects on HUVEC, indicating it might be applied in medical sciences in the future.

Research of Quality Features and Aroma Components in Hunan Fu Brick Tea

SHEN Chengwen, DENG Yuezhao, ZHOU Yuebin, QI Dongqing, HE Qun, TIAN Shuanghong, LIN Juan

Journal of Tea Science. 2017, 37(1): 38-48.

Abstract ( 452 )

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The variations of quality characteristics and aroma components in 15 typical Hunan Fu brick teas were studied by combined simultaneous distillation and extraction (SDE) and GC-MS techniques, sensory evaluation and chemical analysis. Results of sensory evaluation indicated that the main feature of Fu brick tea was fungus fragrance. Some Fu brick teas had a slight taste of retting and smoke, and were not pure enough. GC-MS analysis showed that the alcohol content was the highest (23.01%), followed by acids (18.8%) Ketones (11.10%), aldehydes (9.20%), esters (4.28%), hydrocarbons (3.78%), other categories (2.67%), phenols (0.07) and heterocyclic oxygen compounds (1.06%). Moreover, the main chemical components of Fu brick tea included polyphenols (averagely 10.88%), amino acids (0.66%), caffeine (3.83%), soluble sugar (7.27%) and water extract (31.19%).

Effects of Different Potassium Levels on Main Biochemical Components of Fresh Leaves of Tea Seedlings

ZHONG Qiusheng, LIN Zhenghe, ZHANG Hui, CHEN Zhihui, YOU Xiaomei, SHAN Ruiyang, CHEN Changsong

Journal of Tea Science. 2017, 37(1): 49-59.

Abstract ( 393 )

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Vegetatively propagated 10-month-old tea [Camellia sinensis (L.) O. Kuntze cv. Ruixiang] seedlings grown in pots were fertilized three times weekly for 26 weeks with nutrient solution containing 0, 100, 400, 800 or 2β000βμmol·L^-1 potassium. The effects of different potassium concentrations on the nutritional elements (N, P, K), biochemical and aroma components of tea seedlings were studied. The results showed that the tea plants exhibited potassium deficiency when the potassium concentration was 0 or 100βμmol·L^-1. The potassium contents in the mature leaves of the tea plants were 5.26βmg·g^-1 and 5.91βmg·g^-1, correspondingly. The K-deficiency decreased the root and shoot biomasses, but increased the the ratio of root to shoot. Leaf K content was positively correlated with N and P levels (Y_N=1.045X+11.9065, R²=0.8167. Y_P=0.3075X–0.5706, R² =0.9146 ). Results also showed that K-deficiency decreased the contents of amino acid, caffeine, water extract and EGCG, but increased the contents of tea polyphenol, catechins, EGC, EC and the ratio of tea polyphenol to anmin acid. The contents of arginine, theanine and glutamic acid were significantly decreased in the K-deficient leaves as compared with leaves under normal potassium supply (2 000 μmol·L^-1), which decreased by 86.96%, 72.46% and 40.43% respectively. Aroma component analysis showed that the K-deficient leaves had lower alcohols, aldehydes and esters. Potassium deficiency had a negative effect on the aroma quality of tea leaves.

Effect of Biochar Addition on Ammonia Volatilization in Acid Tea Garden

WANG Feng, CHEN Yuzhen, WU Zhidan, JIANG Fuying, ZHANG Wenjin, WENG Boqi, YOU Zhiming

Journal of Tea Science. 2017, 37(1): 60-70.

Abstract ( 323 )

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Ammonia (NH₃) volatilization is a major reason for nitrogen loss in tea garden soils. Field experiment was carried out to study the effects of biochar on soil physiochemical properties and ammonia volatilization in acid tea gardens, which would provide scientific support for the appropriate application of biochar. Four treatments were included in the experiment, namely no N fertilizer (CK), N fertilizer (B0N1, 225βkg·hm^-2), N fertilizer with 8 t·hm^-2 biochar (B1N1) and N fertilizer with 16 t·hm^-2 biochar (B2N1). The nitrogen was applied three times, namely top dressing in spring, top dressing in autumn and basal dressing in winter in the ratio of 3︰3︰4. Compared with the B0N1 (N-applying only), biochar treatments (B1N1 and B2N1) significantly increased soil pH and organic carbon content (P<0.05), while decreased soil bulk density (P<0.05). Moreover, the average soil NH₄⁺-N and NO₃^--N concentrations in biochar treated soils were 5.34%-12.59% lower and 11.02%-36.54% higher than B0N1, indicating the nitrification was promoted. The total NH₃-N volatilization losses in acid tea garden varied from 13.01βkg·hm^-2 to 40.95βkg·hm^-2 and the percentages of the losses relative to total amount of N-application ranged from 7.29 to 12.42%. NH₃-N volatilization losses also varied significantly among applying stages, with the highest NH₃-N volatilization loss in winter basal dressing. The NH₃-N volatilization increased significantly with N application (P<0.05), but NH₃-N volatilization in B1N1 and B2N1 were significantly decreased by 26.25% and 28.21% (P<0.05), respectively. In summary, the soil NH₄⁺-N concentrations had a direct correlation with NH₃ emission and the reduction of NH₃-N volatilization in biochar treatments might be attributed to the decrease of NH₄^--N concentrations in soils.

Analysis of the Cold Resistance of Baiye 1

ZHANG Lan, LI Xin, WEI Jipeng, LI Zhixin, SHEN Chen, YAN Peng, ZHANG Liping, HAN Wenyan

Journal of Tea Science. 2017, 37(1): 71-77.

Abstract ( 278 )

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The cold resistance was compared in two cultivars, the albino Baiye 1 (Camellia sinensis cv. Baiye 1) during albinism period and Longjing 43 (Camellia sinensis cv. Longjing 43) in Zhejiang province. The results showed that the net photosynthesis rate (Pn) and maximum carboxylation rate of Rubisco (Vc_max) in Baiye 1 during the albinism period were only 70%-80% of those in Longjing 43, but the activities of antioxidant enzymes APX and POD were both 30% higher than those in Longjing 43 under normal temperature. However, when they were treated under 2℃ condition for 24βh, various parameters related to photosynthesis were higher in Baiye 1 than Longjing 43. The activities of APX, POD and SOD were also 38.9%, 33.3% and 23.3% higher in Baiye 1. All the results indicated that the albinism phenomenon of Baiye 1 may lead to the improvement of antioxidant system, which would effectively reduce the H₂O₂accumulation in tea leaves and alleviate oxidative damage and photosynthetic inhibition during cold stress. Therefore, Baiye 1 during albinism period may have a better cold resistance than Longjing 43.

SRAP Marker Analysis of Genetic Diversity and Relationship in Wuyi Rock Tea Germplasm Resources

XIA Fagang, ZHONG Xingwang, WU Feng, JI Biaojun

Journal of Tea Science. 2017, 37(1): 78-85.

Abstract ( 385 )

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The genetic diversity and relationship of 30 Wuyi rock tea germplasms were analyzed by Sequence-related amplified polymorphism (SRAP) markers. Forty three pairs of primers selected from 88 pairs of candidate SRAP primers produced 385 amplified fragments. Among them, 236 were polymorphic, accounting for 61.30% of the total fragments. The results showed that there was distinct genetic diversity within Wuyi rock tea germplasms. The genetic distance ranged from 0.31 to 0.98 with an average of 0.63. Thirty Wuyi rock tea germplasms were classified as three categories basing on the UPGMA cluster analysis. This study was of great significance for genetic research, breeding and resource protection of Wuyi rock tea.

Cloning and Expression Analysis of Geranylgeranyl Diphosphate Synthase Gene CsGGDPS in Tea Plant (Camellia sinensis)

YAO Xueqian, YUE Chuan, YANG Guoyi, CHEN Dan, ZHANG Dongtao, CHEN Guixin, YE Naixing

Journal of Tea Science. 2017, 37(1): 86-96.

Abstract ( 278 )

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A full-length cDNA sequence encoding geranylgeranyl diphosphate synthase (GGDPS) was isolated from transcriptome database of tea plant, cloned from C. sinensis cv. Tieguanyin and named as CsGGDPS. The cDNA length of CsGGDPS was 1β661βbp, with an open reading frame (ORF) of 1β137βbp and deduced protein of 378 amino acids. The protein was deduced to contain 5 conserved domains with 2 functional domains of Isoprenoid-Biosyn-C1 superfamily. The sequence analysis showed that CsGGDPS was highly conserved and had the closest genetic relationship with Panax notoginseng. CsGGDPS was an instability and hydrophilic protein, which was predicted to be located in chloroplast but with no transmembrane structure and signal peptide. There were 20 phosphorylation sites within the polypeptide chain. Alpha helix was predicted to be the major secondary structure of CsGGDPS. The three-dimension structure of CsGGDPS was highly similar to GGPPS11 from Arabidopsis thaliana. The quantitative real-time PCR showed that CsGGDPS expression was increased during the developmental process and increased with the age of tea leaves. Meanwhile, its expression was also enhanced during the Zuoqing procedure. CsGGDPS was ubiquitously expressed in the C. sinensis cv. Huangdan, cv. Tieguanyin and their first filial generation cv. Jinguanyin, but with different expression levels.

Digital Gene Expression Analysis of Tea Flowers without Pistil at Three Development Stages

LI Mei, CHEN Linbo, TIAN Yiping, XIA Lifei, SONG Weixi, LIANG Mingzhi, JIANG Changjun

Journal of Tea Science. 2017, 37(1): 97-107.

Abstract ( 279 )

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The expression patterns of important genes in tea flowers without pistil at the flower bud, alabastrum and florescence stages was studied by the transcriptome and digital gene expression profiling technology. The results found that genes associating with biosynthesis and metabolic activities were highly expressed in tea flowers during the flowering process. Six genes involved in auxin signal transduction and the A、C and E genes of ABCDE model might be closely correlated with the stamen development and response to pistil deletion, which were under complex regulation. The down- regulation of WUS2 and WUS8 in WUS family might also regulate the C and E genes, and result in the deletion of pistil. In the KNOX gene family, none homologous gene of KNOXⅡ was detected. The down-regulation of 3 homologous genes of the KNOX I might weaken the initiation of carpels and the growth of marginal tissues. According to the digital gene expression analysis, a preliminary understanding of the network associating with the pistil deletion and stamen development in tea flower was obtained, which provides a theoretical basis for further research on pistil deletion, stamen development, molecular mechanism of sterility and sex determination in tea plant.

Cloning and Expression Analysis of the Gene Encoding Flavonoid 3′-Hydroxylase in Tea Plant (Camellia sinensis)

WANG Wenli, WU Zhijun, LIU Zhiwei, WANG Yongxin, LI Hui, CUI Xin, ZHUANG Jing

Journal of Tea Science. 2017, 37(1): 108-118.

Abstract ( 380 )

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Flavonoid 3′-hydroxylase (F3′H) belongs to the family of cytochrome P450 monooxygenases (CYP450) and plays important roles in plant secondary metabolism and stress reponses. In this study, a gene encoding F3’H-like protein was cloned by RT-PCR method using a cDNA template from tea (Camellia sinensis) cultivar ‘Longjing43’. This gene is named as CsF3′H1. Sequence analysis showed that the open reading frame of CsF3’H1 was 1,530 bp length, encoding 509 amino acids. CsF3′H1 protein contains the conserved binding domain of P450 enzyme. Analysis of phylogenetic tree showed that CsF3'H1 protein has high similarity with CsF3'H3 protein and has low similarity with CsF3'H2 protein. Multiple alignments showed that CsF3'H1 protein has high similarity with the F3′H homologs from Sorghum bicolor, Actinidia chinensis, Populus trichocarpa, Arabidopsis thaliana, and Vitis vinifera (66.48% identity). CsF3'H1 protein contains the characterized motifs of F3'H-type protein. Analysis of amino acid composition, physical and chemical properties, hydrophilicity/hydrophobicity, and disordered residues of CsF3′H1 protein showed that the disordered residues of CsF3′H1 protein are not obvious and most amino acids of CsF3′H1 protein are hydrophilic. The expression profiles of CsF3′H1 gene in different tissues of tea plant or under hormonal treatments were detected using quantitative real-time PCR analysis. Results showed that: CsF3'H1 gene has the highest expression level in the first leaf. The tissue expression profiles showed that the successive order of CsF3'H1 gene expression levels was the first leaf > the second leaf > the third leaf > the fourth leaf > stem > roo > old leaf. The expression level of CsF3'H1 gene was highest under SA treatment, which was 2.24 times high than the control. CsF3'H1 gene had the lowest expression level under MeJA treatment.

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