Preparation and properties of waste tea leaves particleboard

Urea-formaldehyde （UF） adhesive is the main source of formaldehyde emission from UF-bonded boards. The components in waste tea leaves can react with formaldehyde to serve as a raw material in the production of low formaldehyde emission boards. In our study, waste tea leaves and UF adhesive were employed in the preparation of waste tea leaves particleboard （WTLB）. An orthogonal experimental method was applied to investigate the effects of process parameters on formaldehyde emission and mechanical properties of WTLB. The results indicated that： 1） waste tea leaves had the ability to abate formaldehyde emission from boards; and 2） density of the WTLB was a significant factor affecting its modulus of rupture （MOR）, modulus of elasticity （MOE） and internal bonding （IB）.

Synthesis of activated carbon from spent tea leaves for aspirin removal

Adsorption capacity of activated carbon prepared from spent tea leaves （STL-AC） for the removal of aspirin from aqueous solution was investigated in this study. Preliminary studies have shown that treatment with phosphoric acid （H3PO4） increased removal efficiency of STL-AC. Characterizations on STL-AC revealed excellent textural properties （1200 m2.g-1, 51% mesoporosity）, as well as distinctive surface chemistry （1.08 mmol.g-1 and 0.54 mmol.g-1 for acidic and basic oxygenated groups, pHpzc = 2.02）. Maximum removal efficiency of aspirin observed was 94.28% after 60 rain when the initial concentration was 100 mg.L-1, 0.5 g of adsorbent used, pH 3 and at a temperature of 30 ℃. The adsorption data were well fitted to the Freundlich isotherm model and obeyed the pseudo-second order kinetics model. The adsorption of aspirin onto STL-AC was exothermic in nature （△H = - 13.808 kJ.mol-1） and had a negative entropy change, △S （-41.444 J.mol-1）. A negative Gibbs free energy, △G was obtained indicating feasibility and spontaneity of the adsorption process. The adsorp- tion capacity of △C-STL （178.57 mg.g-1） is considerably high compared to most adsorbents synthesized from various sources, due to the well-defined textural properties coupled with surface chemistry of STL-AC which fa- vors aspirin adsorption. The results demonstrate the potential of STL-AC as aspirin adsorbent.

Development and validation of an analytical method for detecting chlorantraniliprole residues in fresh tea leaves

An efficient method using multiwalled carbon nanotubes(MWCNTs)as dispersive solid-phase extraction sorbent was established for determining chlorantraniliprole residues in fresh tea leaves,which are known to be a troublesome matrix containing abundant pigments,via gas chromatography with an electron capture detector.Acetonitrile was used as the extraction solvent,with sodium chloride enhancing the analyte partition in the organic phase.The optimal mixture of MWCNTs and primary secondary amine(PSA)was based on the distribution of the target analyte recovery and on the clean-up efficiency;while matrix-matched calibration was recommended to combat the matrix effect.Mean recoveries of 95.2%–108.8%were obtained with intraday and interday precisions of less than 7.9%and 10.3%,respectively.Good linearity was observed for concentrations of 0.02–1.0 mg/kg with a correlation coefficient of 0.9984.The limits of detection and quantification were 0.005 mg/kg and 0.02 mg/kg,respectively.The method was employed to investigate the dissipation dynamics of chlorantraniliprole in fresh tea leaves with real field samples.Consequently,the dissipation rates of chlorantraniliprole in fresh tea leaves followed pseudo-first-order kinetics with a half-life of 1.9 d,and the average chlorantraniliprole residue content was below 0.02 mg/kg with a harvest withholding period of 14 d.

Determination of Vitamin B₁₂in Chinese Black Tea Leaves

We determined vitamin B12 content of Chinese black tea leaves using a microbiological assay based on Lactobacillus delbrueckii ATCC 7830. Trace levels (0.25 - 0.69 μg/100g dry weight) of vitamin B12 were detected in Pu’er, Fu, and Brick tea leaves. However, vitamin B12 content (0.06 - 1.37 μg/100g dry weight) of Ryubao tea leaves significantly varied. To determine whether Chinese black tea leaves contain vitamin B12 or other corrinoid compounds that are inactive in humans, corrinoid compounds were purified from Ryubao tea by an immunoaffinity column chromatography and vitamin B12 was identified by liquid chromatography-electrospray ionization/tandem mass spectrometry. Vitamin B12 content in the tea drink prepared from Ryubao tea leaves was very low (0.8 ng/100mL). Our results indicate that Chinese black tea is usually not a good source of B12, although Ryubao tea leaves with the highest B12 content may be utilized as a source of this vitamin for vegerarians.

Determination of 18 Kinds of Amino Acids in Fresh Tea Leaves by HPLC Coupled with Pre-column Derivatization

A rapid and accurate quantitative method of high performance liquid chromatography( HPLC) with fluorescence detector has been developed for the analysis of 18 kinds of amino acids in fresh tea leaves. The samples were minced and mixed,and extracted with ultra pure water at 90℃ for 20 min. The 6-aminoquinolyl N-hydroxy-succinimidyl carbamate( AQC) was used as pre-column derivatization reagent. Gradient HPLC separation was performed on a C_(18) column( Symmetry C_(18),3. 9 mm × 15 cm,4 μm). Good linearity between concentrations and peak areas was achieved in the concentration range of 5. 0-250 μmol/L for 18 kinds of amino acids. The method was validated by the analysis of five replicates. The 18 kinds of amino acid standards were spiked in fresh tea leaf samples and the average recovery rate was 86. 25%-109. 05% with relative standard deviations( n = 5) ranging from 6. 03% to 10. 56%. The limit of detection( LOD) for the analytes was0. 05-1. 27 μmol/L. The method was successfully applied to the analysis of the 18 kinds of amino acids in fresh tea leaves from east Dongting and west Dongting mountains in Suzhou. The results indicate that the method is simple,rapid,precise and reliable.

Utilization of Infused Tea Leaves (Camellia sinensis) for the Removal of Pb2+, Fe2+ and Cd2+ Ions from Aqueous Solution: Equilibrium and Kinetic Studies

In this study, infused tea leaves as a low-cost adsorbent have been used in the removal of the Pb2+, Fe2+ and Cd2+ ions from aqueous solution. The adsorption study was carried out in a batch process and the effects of parameters such as initial pH, adsorbent dose, contact time and initial metal ion concentration were investigated. Experimental results showed that the maximum adsorption of metal ions occurred at pH 5 for Pb2+ and Fe2+ and at pH 6 for Cd2+. Adsorption of metal ions increased with increasing adsorbent concentration and contact time. The isothermal data for the adsorption of metal ions by infused tea leaves were found to fit well with the Langmuir equations. Based on the experimental data of the Langmuir isotherm model, the maximum adsorption capacities of the metal ions onto the infused tea leaves were found in the order of Pb2+ > Cd2+ > Fe2+ with the adsorption capacities of 26.32 mg·gǃ, 14.29 mg·gǃ and 12.38 mg·gǃ respectively. The adsorption process followed the pseudo-second order reaction and the corresponding rate constant were found to be 4.30 × 10Dž g·mgǃ·minǃ, 1.75 × 10ǃ g·mgǃ·minǃ and 1.45 × 10DŽ g·mgǃ·minǃ for Pb2+, Fe2+ and Cd2+ ions respectively.

Aluminum Contents in Dry Leaves and Infusions of Commercial Black and Green Tea Leaves: Effects of Sucrose and Ascorbic Acid Added to Infusions

Tea consumption has increased due to its beneficial effects. Results from a lab study on the effect of sucrose (5 g per cup, 150 mL) and/or ascorbic acid (2 mL per cup, 150 mL) on dissolved aluminum compounds during the infusion of two commercial types of dry tea leaves (black, green) with boiling water (5, 15 min infusion time) are presented. Factors influencing the presence of dissolved aluminum in the infusions of both tea leaves were infusion time and sugar contents, as well as the interaction between ascorbic acid and sucrose (p < 0.05). Aluminum contents found after 15 min of infusion were 0.7 mg L–1 for black tea infusions added with sugar, and 0.69 mg L–1 for green tea added with both sugar and ascorbic acid. Both concentrations are higher than the level accepted in Mexico for drinking water (there is no act concerning tea infusions), that is 0.2 mg L–1.

Investigation of the Aroma Profile of Green Tea Leaves Using Organic Synthesis and Conventional Analytical Techniques

Although many aroma components have been identified in green tea leaves, the aroma compounds contributing to green tea＇s characteristic odor have not yet been reported. The authors recently reported that aroma components with a matcha-like odor are present in both green tea and black tea prepared from the Sayamakaori tea cuttivar. This matcha-like odor is similar to the odor of commercial available matcha （high-quality powdered green tea）, and is a specific odor feature of green tea leaves. At present, the green-tea odor is thought to arise from the combination of a large number of constituents. Recent reports indicate that a complex interaction between olfactory receptors and odorants is important for the evaluation of the odors. Taking into consideration these findings, the authors investigated the aroma profile of green tea, focusing on the characteristic molecular structures of the constituents that give matcha-like odor. Using a combination of organic synthesis and gas chromatography-mass spectrometry plus gas chromatography-olfactometry, the authors identified aroma components with matcha-like odors in five other tea cultivars. This investigation also revealed that several compounds with a formyl group were important constituents of the aroma of green tea leaves, although the odor of each constituent was not individually similar to the tea＇s overall aroma. The authors found for the first time a group of key components that have the matcha-like odor.

Degradation of Dye Wastewater by Pulsed High-Voltage Discharge Combined with Spent Tea Leaves

Degradation of methylene blue （MB） was performed using the pulsed discharge process （PDP） combined with spent tea leaves （STLs）. The effects of STL dosage, concentration of initial solution, and pH were analyzed in the combined treatment. Results showed that the combined treatment was effective for dye wastewater degradation; when the dosage of STLs was 3.2 g/L, the degradation efficiency reached 90% after 15 rain treatment, and STLs showed a good repeatability. The degradation rate decreased with increasing initial MB concentration but not related to the solution pH in the combined treatment. Fourier-transform infrared spectra and N2 adsorption suggested that the number of acidic and basic groups in the STL surface increased after the treatment, but the surface area and pore volume remained unchanged.

Elemental Analysis of Tea Leaves (Camellia Sinensis) and Their Own Soils at Eastern Black Sea Region in Turkey

People consume tea brewed from the leaves of the Camellia sinensis plant for about 50 centuries. Health benefits of the tea have been investigated for about three decades. Especially green tea shows antitoxic and lots of properties with its determined ingredients. Turkey is not only the one of the best consumer and but also good producer of the tea as being 5 th producer all over the world. It grows eastern region of the Turkey and high quality tea is imported and exported. To have quality tea, grooving soils are also crucial. In the current research, Tea leaves and their own grown soils were collected from 20 stations where the most tea producer cities as Trabzon, Rize and Artvin tea fields of the eastern of Black Sea Region in Turkey. The cultivated tea and their own grown soil samples were analysed by using EDXRF Spectrometry. In the soil samples, the elements Mg, Al, Si, P, S, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Sr, Ba, Pb on percent level and the elements Mg, Al, Si, P, Cl, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn and Sr in the tea leaves were detected by using SKRAY 3600-EDXRF.and also the obtained data were evaluated with the Kriging interpolation of geostatistical method. Element content were investigated in the soil and tea samples according to the geological situations and also the relation of elemental difference between the tea and the own grown soil. Pb/Zn ratio was also anaysed in the samples.

Changes in Polyphenols and Antioxidant Activities of Yingshan Yunwu Tea during Digestion in Vitro

[Objectives]To explore the change rule of polyphenol content and antioxidant activity of coarse old leaves of Yingshan Yunwu Tea in the process of human digestion.[Methods]The coarse and old leaves of Yunwu tea in Yingshan,Huanggang,Hubei Province were selected as the research object,and their digestion in vitro was simulated.The total polyphenol content was determined by Folin-phenol reagent colorimetric method,and the DPPH radical scavenging activity and total antioxidant activity were determined.[Results]After simulated gastrointestinal digestion in vitro,the polyphenol content and antioxidant activity of coarse old leaf tea soup showed a downward trend.After gastrointestinal digestion,the polyphenol content in tea infusion separately decreased by 31.8%and 8.5%;the scavenging rate of DPPH free radical was 97%before digestion,decreased to 92%after gastric digestion and 65%after intestinal digestion,which decreased by 5%and 27%,respectively;after gastrointestinal digestion,the total antioxidant capacity of tea soup decreased by 4.7%and 3.1%,respectively.[Conclusions]This study provided a reference for the development and application of coarse old leaves of Yingshan Yunwu tea,and provided a reference for the nutritional value evaluation and comprehensive utilization of coarse old leaves,so as to make the best use of coarse tea leaves and reduce the waste of resources.

Study on Dishes with Longjing Tea Leaves as Spice

As one of the top ten Chinese teas, Longjing Green Tea is famous for its green tea leaves, sweet taste, pleasant aroma and beautiful shape. Besides of using as drinks, Longjing tea leaves can be applied as spice in Chinese cuisine for its particular taste and function. Under the background of pursuing healthy cuisine, the development of organic Longjing tea and advocate of Chinese tea culture have great economic and culture significance.

Adsorptive Removal of Heavy Metals from Aqueous Solution with Environmental Friendly Material—Exhausted Tea Leaves

In this study adsorptive removal of Pb(II) and Cu(II) from aqueous solution by using environmental friendly natural polymers present in exhausted tea leaves has been studied. The biosorbent was modified with dimethylamine to introduce N-functional groups on the surface of adsorbent. The modified adsorbent was characterized by elemental analysis, zeta potential analysis, SEM, DRFTIR, XRD and TG/DTA analysis to conform the modification. Adsorption capacity of the adsorbent was determined as the function of pH of the solution, initial concentration of the solution and contact time. The adsorption experiments were performed using batch experiments. The maximum adsorption capacities of the adsorbent were found to be 91.68 and 71.20 mg/g for Pb(II) and Cu(II), respectively. To minimize the process cost, regeneration of the biosorbent and recovery of metal ions was explored by desorption study. The results indicate that the adsorbent holds great potential for the sequestration of Pb(II) and Cu(II) from their aqueous solution. Hence the modified exhausted tea leaves (MTL) have been investigated as a new cost effective and efficient biosorbent for removal of Pb(II) and Cu(II) from their aqueous solution.

Selenium-enriched oolong tea(Camellia sinensis)extract exerts anti-inflammatory potential via targeting NF-κB and MAPK pathways in macrophages

Both tea polyphenols and selenium(Se)have been suggested to exert the health benefits via the regulatory capacities of chronic inflammation,which make Se-enriched oolong tea a promising beverage as an anti-inflammatory diet.The aim of this study is to investigate the anti-inflammatory effects of Se-enriched oolong tea extract(Se-TE)and underlying mechanism in lipopolysaccharide(LPS)-induced RAW264.7 cells.Se-TE treatments(50 and 150μg/m L)significantly suppressed the over-production of nitric oxide(NO)and prostaglandin E2(PGE2)in LPS-stimulated macrophages via downregulating the expression of nitric oxide synthase(i NOS)and cyclooxygenase-2(COX-2).Moreover,Se-TEs also effectively inhibited the productions of inflammatory cytokines,such as tumor necrosis factor-α(TNF-α),interleukin-6(IL-6),and interleukin-1β(IL-1β).Furthermore,Se-TE could block mitogen-activated protein kinase(MAPK)and nuclear factor-kappa B(NF-κB)signaling pathways through the inhibition of the phosphorylation of key proteins(IκB-α,p65,p38,ERK,and JNK)and the translocation of the p65 subunit into the nucleus.Collectively,our results indicated that Se-TE may have the potential to be used as a novel food ingredient for the development of various anti-inflammatory foods and the treatment and prevention of chronic inflammation-related diseases.

早青与晚青乌龙茶的挥发性成分差异

为探明鲜叶不同采摘时段对乌龙茶香气化学特征的影响,本研究将铁观音早青与晚青按传统工艺加工成乌龙茶,运用气相色谱-质谱法分析鲜叶和乌龙茶的挥发性成分,比较早青茶与晚青茶中挥发性成分的差异。结果表明,晚青茶所含挥发性组分总量比早青茶少28.3%,醇类化合物的含量及占比均处优势,尤其是异植醇和反-橙花叔醇。挥发性成分在鲜叶与乌龙茶中的组成特征差异较大,醇类和酸类化合物在鲜叶中的占比相近,但在乌龙茶中二者差异较大;早青与晚青包含56种共有挥发性成分,比其乌龙茶的共有成分多4种,但在鲜叶与乌龙茶共有42种成分中十六烷酸、二氢猕猴桃内酯、反-橙花叔醇、异植醇等受加工工艺的影响明显,且变化幅度较大。可见晚青与早青中挥发性成分的分布特征相异,晚青茶优于早青茶且清香突出。

肉桂茶纯露挥发性成分分析

分析肉桂茶纯露和茶叶之间挥发性成分差异,为肉桂茶纯露的开发利用提供科学依据。采用顶空-气质联用法检测肉桂茶茶叶和水蒸气蒸馏提取的肉桂茶纯露中挥发性成分。结果表明:从肉桂茶纯露和茶叶中分别鉴定出55种、12种挥发性成分,含醇类、醛类、萜烯类、酯类、生物碱类、酮类等10类成分,其中肉桂茶纯露以醇类成分的数量最多,达10种,醛类成分的相对含量最高,达38.92%,相对含量较高的挥发性成分有2-甲酰组胺、2,4a,5,6,7,8,9,9a-八氢-3,5,5-三甲基-9-亚甲基-1H-苯并环庚烯、S-甲基-半胱氨酸、异丁醛、2-甲基丁醛、异戊醛、正己醛,相对含量分别为17.91%、15.20%、14.51%、14.37%、11.93%、7.91%、3.41%。肉桂茶纯露能很好的还原茶叶的香气,且香气成分数量和种类更多,香气层次更丰富,具有花香、果香等多种香韵。

40个福建茶树品种叶片元素生态化学计量特征

【目的】探索同一生境条件下不同茶树品种对大量元素的同化利用特征。【方法】对40个福建茶树品种的叶片C、N、P与K元素含量及其化学计量比进行分析,并采用主成分与聚类分析对元素计量等10种特征指标进行综合评价。【结果】茶树叶片有机C、全N、全P和全K含量及其化学计量比等10种指标,除P、C/K、N/K与P/K为非正态分布外,其余C、N、K、C/N、C/P及N/P均呈正态分布。有10个品种N/P值<14,为N限制;有25个品种N/P值>16,呈P限制。以欧氏距离17为临界值,通过聚类分析可将40个品种分为3大类群,其中第Ⅲ类群N/P值<14,呈N限制;而占总数的75%的品种归在第Ⅰ、Ⅱ类群,其N/P值均>16,呈P限制。通过主成分分析,可将10种元素特征参数提取成3个主成分,占解释总方差91.88%。主成分综合评价排名前6位的茶树品种依次为:金牡丹、大叶乌龙、朝阳、金观音、铁观音、大红袍;与叶片高N、P含量的品种高度一致。【结论】N、P元素及其比值可作为元素生态化学计量主成分评价的重要影响因素。本研究可为高N、P同化潜力的种质资源评价、茶树新品种选育及亲本选择提供参考。

三种消解方法比较原子荧光光谱法检测富硒米和茶中硒含量

以原子荧光光谱法测定富硒米和茶中硒的含量,适当的消解方法可以节约样品处理效率,提高检测结果的准确性。分别采用微波消解法、电热板消解法和石墨管消解法对富硒米和茶进行消解处理,比较不同消解方法对富硒米和茶中硒含量的检测影响。结果表明:微波消解法更适合富硒米和茶的消解处理,其加标回收率为95.0%~100.5%,精密度小于3.0%,加标回收率及精密度优于电热板消解法和石墨管消解法;相比电热板消解法和石墨管消解法,微波消解法试剂使用量少、操作方便快捷、稳定性好。可以为富硒农产品相关检测从业者提供参考。

基于感官评价和代谢组学分析叶用枸杞茶

以26个品种(系)叶用枸杞芽叶干样及鲜叶为材料,采用感官评价和代谢组学技术并结合多元统计分析对其感官品质和代谢物进行分析。感官评价结果表明,叶用枸杞芽叶干样滋味醇厚、鲜爽、有甜味;液相色谱-质谱联用结果显示,叶用枸杞芽叶中共鉴定出879种代谢物,包括氨基酸及其衍生物、黄酮类、酚酸类、糖类、核苷酸及其衍生物、木脂素和香豆素、生物碱、萜类、有机酸、脂质10类。根据偏最小二乘判别分析模型及单因素方差分析筛选出211种差异代谢物,主要富集在亚油酸代谢、类黄酮生物合成、黄酮和黄酮醇生物合成、苯丙醇生物合成、半乳糖代谢等代谢通路,此外还发现,氨基酸及其衍生物、黄酮、糖类和脂类是区分不同品种(系)叶用枸杞芽代谢物的重要组分。偏最小二乘回归(partial least squares regression,PLSR)分析表明,表儿茶素、异槲皮素、芦丁等26种代谢物共同影响叶用枸杞茶醇、厚、鲜、甜和苦等滋味。感官评价结合PLSR分析结果表明,‘宁杞菜1号’‘宁杞9号’、Z90、Z68、Q3、Q6-13和Z487种叶用枸杞具有感官品质较好且滋味物质丰富的特点。

盈江大理茶种与凤庆大叶种芽茶香气差异分析

为探究云南盈江大理茶种与凤庆大叶种芽茶香气的组成和差异,本研究通过感官审评、顶空-固相微萃取与气相色谱质谱联用(Headspace solid-phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GCMS)的方法,对盈江大理茶种芽茶(通常称为芽孢茶,记为芽孢红茶YBH,芽孢白茶YBB)及凤庆大叶种芽茶(记为凤庆红茶FQH,凤庆白茶FQB)的挥发性成分进行鉴定和分析。HS-SPME-GC-MS检测结果表明:4个茶样共检测出16类共616种挥发性代谢物;主成分分析(Principal component analysis,PCA)和正交偏最小二乘法判别模型(Orthogonal partial least squares-discriminant analysis,OPLS-DA)分析表明:两个品种的红茶对比中,YBH检测到8种特有差异代谢物,FQH检测到7种;两个品种的白茶的对比中,YBB检测到3种特有差异代谢物,FQB中检测到4种;主要特征差异挥发性代谢物的气味活度值(Odor activity value,OAV)评估表明:(Z)-癸-2-烯醛和香叶醇是区分盈江大理茶种芽孢茶和凤庆大叶种的潜在特征香气,(Z)-癸-2-烯醛(OAV>100)是盈江大理茶种芽孢茶的重要香气成分,推测大马士酮(OAV>1)是YBH产生浓郁花果香的关键物质,己酸和乙酸芳樟酯可能是YBB呈自然清花香的主要物质;β-紫罗兰酮(OAV>10)是凤庆大叶种的重要香气成分,推测苯乙醛(OAV>1)是FQH呈花香的主要物质,(Z)-癸-2-烯醛和己酸是FQB呈花香和毫香的主要物质。综上所述,盈江大理茶种芽孢茶的香气成分较对照品种丰富且YBH香气更馥郁。