Effects of High-intensity Pulsed Electric Field on Amino Acid Content in Large-leaf Pu'er Tea Variety

[Objective] This study aimed to test the effects of high-intensity pulsed electric field on the amino acid content in Pu’er tea leaves. [Method] The amino acid contents of fermented and unfermented the leaves of large-leaf Pu’er tea variety produced in Yunnan Mengku, were measured before and after the treatment with high-intensity pulsed electric field （HPEF）. [Result] The difference of amino acid contents was notable between fermented and unfermented tea leaves produced in the same year. The amino acid content of unfermented tea leaves was larger than that in fermented tea leaves. The amino acid content in tea leaves decreased over time during storage. HPEF treatment under al the conditions improved the amino acid content in tea leaves. [Conclusion] This experiment provides theoretical foundation for the application of HPEF in processing of Pu’er tea leaves.

Inhibitory Effects of Pu-erh Tea Leaves on Mouse Type IV Allergy

Pu-erh tea is one of post fermented tea manufactured through oxidative maturing by microorganisms. We investigated the preventive effects of pu-erh tea extract on oxazolone-induced type IV allergy in male (ICR) mice. Oral administration of 50 mg/kg water extract of pu-erh tea leaves resulted in significant preventive effects against mouse type IV allergy. The hydrophilic Theabrownin-like fraction (TBW-ND), with a high molecular weight of approximately 12,000 or higher, was prepared from pu-erh tea leaves by a solvent-extraction method, followed by Diaion HP-20 column chro-matography and dialysis. Oral and percutaneous administrations of TBW-ND at doses of 18.7 mg/kg and 0.037 mg/ear also resulted in significant preventive effects, which included preventing increases in levels of the proinflam-matory cytokine interleukin-12. The anti-allergic ingredients in TBW-ND were predicted to be highly complex compounds containing of polyphenols, polysaccharides and/or proteins. The results suggest pu-erh tea leaves could be a beneficial food for protecting against delayed-type allergy.

Anti-Obesity, Anti-Atherosclerotic and Anti-Oxidant Effects of Pu-Erh Tea on a High Fat Diet-Induced Obese Rat Model

Pu-erh tea, a traditional Chinese beverage, has been believed to have many benefits to human health and without side effects. In this study, we systematically analyzed the main active components of Pu-erh tea and investigated its anti-obesity, anti-atherosclerotic and anti-oxidant effects using an obese rat model. Obesity was induced by feeding a high-fat diet and subsequently the experimental obese mice were fed with high-fat diet supplemented with low (2.5%), medium (5%) or high (7.5%) doses of Pu-erh tea powder for 6 weeks respectively. As result, the body weight gain of the rats was decreased by medium and high doses of Pu-erh tea treatments. Furthermore, the levels of serum total cholesterol (TC), triglyceride (TG) and atherosclerosis index (AI) were significantly lowered by Pu-erh tea compared to the control group. Conversely, high density lipoproteincholesterol (HDL-C) level of the rats was significantly elevated by Pu-erh tea treatments. In addition, Pu-erh tea treatments increased the activities of anti-oxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxides (GSH-Px), whereas reduced the level of lipid peroxidation product malondialdehyde (MDA) in obese rats. Collectively, our find-ings revealed that Pu-erh tea exerts comprehensive benefits in anti-obesity, anti-atherosclerotic and anti-oxidant effects, therefore can be used as a promising functional food in obesity management.

Discussion on the Sustainable Development of Pu'er Tea

The current situation of Pu'er tea in Yunnan was analyzed.The analysis result showed that the production output of Yunnan tea and the tea plantation area increased greatly when compared with the whole country,but the increase of Pu'er tea inclined to be stable.The restraining factors of Pu'er tea development were explored,and the corresponding countermeasures were put forward.It provided the basis for the sustainable development of Yunnan Pu'er tea.

Effects of different de-enzyming methods on microbial composition and volatile compounds of raw Pu’er tea based on microbiome and metabolomics

Microorganisms play a significant role in the quality formation of raw Pu’er tea,and volatile compounds mainly contribute to the aroma quality.However,different de-enzyming methods on the quality of raw Pu’er tea has not yet been reported.Microbiome and metabolomics were employed to comprehensively compare and analyze microbial community and volatile compounds in machine de-enzyming raw Pu’er tea(JS)and manual de-enzyming raw Pu’er tea(SS)in this study.High-throughput sequencing results showed that bacterial and fungal community compositions of JS and SS samples at phylum and genus levels were essentially identical,differed in relative abundance.A total of 65 and 71 volatile compounds were detected and characterized in JS and SS samples,respectively.Volatile components in JS and SS samples were mainly composed of alcohols,esters,aldehydes,alkanes,benzene and its derivatives,ketones,alkenes,phenols.A total of 88 differential volatile components between JS and SS samples were screened based on VIP>1 and p-value<0.05.Those results indicated that both microbial community composition and volatile compounds in raw Pu’er tea influenced by different de-enzyming methods.This work helps reveal the effect of different de-enzyming methods on the quality of raw Pu’er tea and provide a scientific reference basis for the improvement of raw Pu’er tea quality.

The Story of Pu’er Tea Farmers in Yunnan

LISA See is the New York Times bestselling author of Snow Flower and the Secret Fan and many other popular books. Her new novel, The Tea Girl of Hummingbird Lane, soon topped the newspaper’s list of bestsellers after its publication in 2017 by Scribner Books and was reprinted in April 2018. More than 1,500 readers have written their reviews on the online platform of Amazon and Goodreads after reading the book.

Anomaly of the ionospheric electron density close to earthquakes:Case studies of Pu'er and Wenchuan earthquakes

The electron density recorded onboard the DEMETER satellite was analyzed to search for possible anomalies before earthquakes both in space and time. To distinguish pre-earthquake anomalies from the other anomalies related to geomagnetic activity, data were filtered using the Kp index. The analysis is based on the comparison of data recorded closely to earthquakes in space and time and past data for the same area. In analyzing data around the time and location of the Pu＇er and Wenchuan earthquakes, obvious anomalies in electron density were found close to the epicenters, and some remarkable disturbances were detected before the earthquakes occurred. The results were finally compared with those of previous works that used the same data but employed different analysis methods. Good agreement was found which suggests that these anomalies have a close relation to the earthquake preparation.

高效液相色谱法测定普洱熟茶中Puerins 401系列化合物的含量

文章建立了测定普洱熟茶中Puerins 401系列化合物含量的高效液相色谱分析方法。普洱熟茶中Puerins 401系列化合物用水提取,经二氯乙烷萃取,HP20自装柱富集净化,净化液经Waters Atlantis dC18色谱柱分离,以2 mmol/L乙酸铵水溶液(含1‰甲酸)和乙腈为流动相进行梯度洗脱,检测波长280 nm,流速1 mL/min,外标法定量。结果表明,在2.0~500.0 mg/L范围内,Puerins 401系列化合物线性关系良好,相关系数0.999。Puerins 401系列化合物最低检出限为3.6 mg/kg,最低定量限为11.9 mg/kg,加标回收率75.0%~99.5%,相对标准偏差均小于5%。该方法灵敏度高,准确性好,适用于普洱熟茶中Puerins 401系列化合物的测定。

Pu’er raw tea extract alleviates DSS-induced colitis in mice by restoring intestinal barrier function and maintaining gut microbiota homeostasis

Numerous investigations have uncovered the outstanding therapeutic effect of tea extract on ulcerative colitis(UC).However,the therapeutic potential on UC of Pu’er raw tea extract(PRTE)remains debated and need to be investigated.In our study,PRTE(100 and 300 mg/kg)was applied to the DSS-induced colitis mice via intra-gastric administration.Results have shown that PRTE treatment significantly ameliorated DSS-induced weight loss,loose stool,hematochezia,colon atrophy,splenomegaly and colon pathological injury.It could also inhibit UC by down-regulating pro-inflammatory cytokines(IL-1β,IL-6 and TNF-α)and increasing the expression of tight junction protein(zonula occludens-1,ZO-1)to reinforce intestinal barrier.Fecal microbiota transplantation has further confirmed that PRTE could maintain intestinal homeostasis and relieve UC by improve the abundance of beneficial bacteria such as Lactobacillus,Muribaculum,Lachnospiraceae and Rikenellaceae,and reduce the abun-dance of harmful bacteria such as Turicibacter and Romboutsia.This study suggested that PRTE exhibited a noteworthy therapeutic effect on UC via restoring intestinal barrier function and maintaining gut microbiota homeostasis,which develops a safe and efficient novel strategy for UC prophylaxis and therapy,and provides theoretical support for medical application of Pu’er raw tea in the future.

普洱生茶和普洱熟茶多酚降脂作用比较研究进展

普洱茶及其多酚成分可通过抑制脂肪细胞分化、调节脂质代谢及改善肠道菌群等降低脂质积累和预防肥胖发生。普洱生茶和普洱熟茶具有不同的多酚成分,通过不同作用机制调节脂质代谢。比较普洱生茶和普洱熟茶多酚的降脂减肥功效及其作用机制,旨在为进一步研究普洱茶降脂功效提供参考。

基于普洱茶中重金属成分检测标准物质长期稳定性的研究

本文对所研发的普洱茶中重金属成分检测标准物质的长期稳定性进行了研究,阐述了该标准物质长期稳定性的研究理论及方法。该研究引用经典稳定性评估方案,采用电感耦合等离子体质谱方法,应用标准曲线分析规则(内标法),对普洱茶中Cr、Cu、Cd等重金属元素成分检测标准物质的长期稳定性进行了考察。结果表明:该实验可用于检验普洱茶中重金属成分检测标准物质的性能与品质。

2018年9月8日墨江5.9级地震云南普洱大寨流体异常特征及机理

文中梳理了2004年以来普洱大寨井连续观测的水化学离子和井-含水层渗透性异常特征。研究发现,在观测井周边250km范围内5.5级以上地震发生前,多次出现过可重复、可类比的异常变化,对地震具有较好的异常指示和预测意义。但相比以往震例,墨江5.9级地震发生前,无论是化学离子还是物理参数均出现了观测以来幅度最大的变化,异常状态较以往强烈很多,但发震的震级只有5.9级。为了研究这一现象产生的原因和机理,文中尝试从区域深部物质活动和区域应力水平2个方面对墨江5.9级地震前的异常演化过程开展讨论,得到以下认识:墨江5.9级地震前,流体异常整体呈现出较为显著的从深部到浅部、从背景到短期微观异常再到临震宏观异常的演化过程;墨江5.9级地震前,普洱大寨连续观测的水化学离子浓度异常和井-含水层渗透性的改变是由于区域内垂向剪切应力持续增强引起的含水层受挤压,从而形成了垂向的流体补给,最终引起不同含水层水体发生交替混合而产生的结果;本次异常形成初期还伴随深部物质剧烈活动的现象,较为显著的由深部到浅部的耦合作用过程可能是导致墨江5.9级地震前出现自观测以来地下流体异常幅度最显著的原因。因此,流体活动从深部开始,随着区域应力不断积累,不断向地表传递的演变过程是墨江5.9级地震前流体异常演化的本质特征;区域应力的作用方式和深部物质活动程度不同,是引起墨江5.9级地震前异常特征与研究区其他历史震例前明显不同的根本原因。文中研究为全面认识普洱大寨井地下流体异常的预测意义和地震前流体异常的深浅耦合演化过程提供了一定参考。

红曲霉与植物乳杆菌发酵普洱茶的抗氧化活性比较

该文探究添加红曲霉和植物乳杆菌发酵对普洱茶生化成分和抗氧化活性的影响。采用相关系数法分析主要生化成分和抗氧化指标的相关性。实验表明,六个发酵茶样的水浸出物、黄酮、茶多酚含量范围分别是50.64%~52.50%、0.77~0.95mg/g、13.21%~11.07%,单接植物乳杆菌R的茶多酚含量最高为13.21%。不同处理的茶样体外抗氧化能力存在显著差异(P<0.05),R的总抗氧化能力、DPPH自由基清除率和羟自由基清除率最高(10.36μgTrolox/mL、91.59%、29.43%)。相关性显示,茶红素、茶褐素与抗氧化能力呈负相关,但不显著;咖啡碱、茶多酚、茶黄素、总黄酮指标与抗氧化能力都有一定的显著相关性,其中茶多酚与总抗氧化能力、DPPH自由基清除率呈极显著相关(P<0.01),相关系数为0.74、0.95。添加菌种发酵的普洱茶具有较强抗氧化能力,且单菌种发酵普洱茶的抗氧化能力比混合发酵普洱茶的抗氧化能力更强,其中R的抗氧化能力最好。

近红外光谱法快速测定晒青毛茶三种儿茶素组分含量

为了实现晒青毛茶儿茶素含量的快速检测,该研究利用高效液相色谱技术(High Performance Liquid Chromatography,HPLC)测定了50份晒青毛茶样品中的表没食子茶素没食子酸酯(Epigallocatechin Gallate,EGCG)、表没食子儿茶素(Epigallocatechin,EGC)、没食子酸(Gallic Acid,GA)三种儿茶素单体含量,结合样品的近红外光谱,分别建立了晒青毛茶三种儿茶素单体含量的偏最小二乘法(Partial Least Squares,PLS)模型,并对模型进行验证。实验结果表明,基于EGCG、EGC、GA含量所建立近红外模型的决定系数(Coefficient of Determination,R2)分别为99.99%、99.99%、99.92%;校正标准差(Root Mean Square Error of Calibration,RMSEC)分别为0.17、0.15、0.10;相对标准差(Relative Standard Deviation,RSD)分别为0.19%、0.27%、0.56%;外部验证的结果显示,三种儿茶素单体含量模型的预测值与真实值的平均绝对误差分别为0.13、0.12、0.07;平均相对误差分别为0.17、0.25、0.45。实验结果表明,该研究建立的近红外分析模型具有较高的预测准确度和稳定性,在快速检测晒青毛茶儿茶素方面具有潜在应用价值。

普洱茶素Ⅴ~Ⅶ对4种乳腺癌细胞作用研究

普洱茶素(Puerins)是从普洱熟茶中分离得到的儿茶素衍生物,是一类结构独特的含氮多酚化合物。开展普洱茶素Ⅴ~Ⅶ抗乳腺癌细胞作用的研究,以4种不同受体表型的乳腺癌细胞株为模型,进行噻唑蓝(MTT)比色试验、蛋白质组学检测及细胞凋亡检测等试验。结果表明,普洱茶素Ⅴ、Ⅵ和Ⅶ等3个单体化合物对4种乳腺癌细胞都有显著的抑制作用;蛋白质组学分析发现,普洱茶素干预后乳腺癌细胞表达产生差异的蛋白主要集中于代谢通路,其次是癌症通路和黏附斑信号通路;细胞凋亡检测发现3个普洱茶素化合物均可诱导MDA-MB-231细胞的凋亡。本研究报道了普洱茶素Ⅴ~Ⅶ的抗乳腺癌细胞活性及初步作用机制,为研究普洱熟茶抗癌活性物质提供基础信息。

基于响应面法优化沙棘普洱茶粉水提工艺及体外抗氧化能力评价研究

以沙棘普洱茶粉水提液中可溶性固形物为响应值,基于单因素及Box-Benhnken响应面法优化实验研究不同料液比、时间、温度、pH的影响.对不同原料配比下的沙棘普洱茶粉进行有效成分检测及体外抗氧化实验,分析、评价其体外抗氧化能力.得到沙棘普洱茶粉(沙棘叶∶普洱茶末=4∶1)的最优水提工艺条件为料液比(原料∶水)为1∶8(g/mL)、提取温度为79℃、提取时间为3 h、pH为8.3.沙棘普洱茶粉的活性成分含量较单一茶粉有所提高,对DPPH(2,2,-diphenyl-1-picrylhydrazyl)、ABTS(2,2′-azinobis(3-ethylbenzthiazoline-6-sulfonic acid)、CuPRAC(Cupric ReducingAntioxidant Power)及FRAP(Ferric Reducing Antioxidant Power)均具有较强的清除能力,制备的沙棘普洱茶粉均具有较好的体外抗氧化作用,为沙棘、普洱茶资源利用及功能性茶粉的开发提供一定参考.

不同蒸压工艺下普洱茶抗氧化活性差异比较

目的探究不同蒸压工艺对普洱茶抗氧化活性的影响。方法本研究在普洱茶压制环节中设置不蒸压的原始样、蒸汽样、湿闷样、压饼打散样、压饼烘干样5种处理,采用分光光度法检测不同蒸压工艺下普洱茶总抗氧化能力、羟自由基清除能力、1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基清除率、超氧阴离子自由基清除能力并分析其差异。结果生茶总抗氧化能力压饼烘干样最大,显著高于湿闷样0.02 mol/L;生茶羟自由基清除能力湿闷样最高,显著高于原始样69.05 U/mL;生茶DPPH自由基清除率湿闷样最高,显著高于压饼打散样15.75%;生茶超氧阴离子自由基清除能力湿闷样最高,显著高于压饼打散样763.49 U/L。熟茶总抗氧化能力压饼烘干样最高,显著高于原始样0.07 mol/L;熟茶羟自由基清除能力湿闷样最高,显著高于原始样57.72 U/mL;熟茶DPPH自由基清除率湿闷样最高,显著高于原始样34.45%;熟茶超氧阴离子自由基清除能力压饼烘干样最高,显著高于压饼打散样1065.65 U/L。结论经过蒸压工艺中的压饼打散处理后,普洱生茶、普洱熟茶抗氧化活性降低,蒸汽、湿闷、压饼后烘干处理有利于其抗氧化活性提高,为普洱茶蒸压工艺的改进和抗氧化活性的提升提供理论基础。

普洱茶茶渣对茶花鸡2号肉品质的影响

试验旨在探讨饲粮中添加不同水平普洱茶茶渣对茶花鸡2号肉品质的影响。选取144只茶花鸡2号,随机分为3组,每组6个重复,每个重复8只。对照组饲喂基础饲粮,1%和2%茶渣组分别在基础饲粮上添加1%和2%的普洱茶茶渣,试验期28 d,试验结束进行鸡肉品质测定。结果表明:①与对照组相比,1%和2%茶渣组胸肌和腿肌肉品质物理特性(L^(*)值、a^(*)值、b^(*)值、pH4_(5min)、pH_(24h)、失水率、蒸煮损失率、剪切力)和常规营养成分(粗蛋白、粗脂肪和粗灰分含量)无显著差异(P>0.05),1%茶渣组胸肌各氨基酸含量以及2%茶渣组腿肌各氨基酸含量无显著差异(P>0.05)。②与对照组相比,2%茶渣组胸肌Asp、Thr、Ser、Glu、Ala、Cys、Val、Ile、Leu、Tyr、Lys、UAA和TAA含量极显著降低(P<0.01),Met、Phe、His、Arg、SAA、BAA、EAA和NEAA含量显著降低(P<0.05),Gly和Pro含量无显著变化(P>0.05),1%茶渣组腿肌Tyr含量极显著降低(P<0.01),Asp、Thr、Ser、Glu、Ala、Val、Ile、Leu、Phe、Lys、Arg、UAA、SAA、BAA、EAA、NEAA和TAA含量显著降低(P<0.05),Gly、Cys、Met、His和Pro含量无显著变化(P>0.05)。由此可见,饲粮中添加1%和2%普洱茶茶渣分别降低了茶花鸡2号腿肌和胸肌氨基酸含量,降低了肌肉风味。

普洱茶中一株产纤维素酶黑曲霉的分离及鉴定

目的分离、鉴定普洱茶中一株产纤维素酶的黑曲霉(Aspergillus niger)菌株。方法对从普洱茶中得到霉菌菌株进行富集培养和纯化分离,后经过刚果红染色法初筛以及滤纸酶活力法复筛,得到具有较强产纤维素酶能力和较高纤维素酶活力的目的菌株,并测定其酶活力。结果从普洱茶中分离得到24株霉菌菌株,经初步筛选得到7株具有较强产纤维素酶能力的菌株,水解圈直径与菌落直径最大比值达1.76,通过测定滤纸酶活力复筛得到一株具有较高纤维素酶活力的菌株,在发酵第9d时其纤维素酶活力达到16.58U/m L。结合菌落和显微形态鉴定以及菌株ITS基因序列分析确定该菌株为黑曲霉,菌株命名为XO-18。结论本研究筛选获得产纤维素黑曲霉XO-18,该菌株产酶活力高,具有开发成食品工业发酵用菌,满足食品工业需求的潜力。

基于体外肠道微生物消化预测不同工艺大叶茶的健康作用

大叶茶是我国重要的茶树品种,茶叶成分组成的差异影响肠道微生态、糖脂代谢等。该研究比较了经不同工艺制备而成的大叶种白茶、普洱生茶、普洱熟茶及酸茶对不同人群肠道微生态的影响。利用正常及肠杆菌型便秘人群的粪便样本构建体外肠道微生物消化模型,与茶汤共培养1 d后,测定发酵液的微生物组成及短链脂肪酸含量,并进行PICRUSt2代谢通路预测。在2种模型中,大叶茶均降低厚壁菌门/拟杆菌门比值,促进瘤胃球菌、毛螺菌、真细菌、丁酸球菌等产丁酸菌、嗜黏蛋白阿克曼菌丰度增加,抑制链球菌、葡萄球菌等致病菌,提高短链脂肪酸含量。在普通模型中,消化、能量及脂质代谢、外源化合物生物降解、肠道炎症保护等代谢途径被显著干预,而在便秘模型中,仅心血管健康和循环系统相关的2条代谢途径被普洱熟茶显著干预。与其他大叶茶相比,普洱熟茶组较为显著地提高了肠道菌群多样性,酸茶最为显著地增加了便秘模型的短链脂肪酸含量。