Processing Technology and Quality of Low-fluoride Brick tea

In order to promote the quality of brick tea and reduce its fluoride content, the fluoride contents in leaves of 25 tea varieties at the .stage of one bud and five leaves were determined by the method of fluodde-ion selective electrode method. The results showed that the fluodde contents in the 25 varieties were in the range of 181.92-345.06 mg/kg, end the fluoride content in ＇Zhongcha 302＇ was the lowest. Based on traditional production process of brick tea, 3 new low-fluoride brick tea production processes with ＇Zhongcha 302＇ as the raw material at the stage of one bud and five leaves were constructed. The fluoride content, physicochemical in- dex, sensory end main chemical contents in the brick tea samples were determined. The best processing process of Iow-fluodde brick tea was process 3, which included aldng, fixing, rolling, second fixing, second roiling, sun-drying, pile-fermentation, steaming, pile-fermentation, drying and shaping into brick by vapor treating. The re- sults showed that the fluoride content and physicochemical index of the brick tea sample of the third low-fluoride brick tea production process accorded with National Standard GB/T 9833.4-2013. The sensory evaluation of the brick tea sample was better than that of brick tea manufacture by the traditional process. The water extract, tea polyphenols, amino acids, caffeine and water-soluble sugar in the brick tea sample increased by 9.41%, 36.39%, 26.94%, 27.23% and 15.29%, respectively. Low-fluodds bdck tea could be produced by selecting low fluoride tea varieties, controlling the tondemess of fresh leaves, and optimizing the processing technique.

Comparative study on Leaf Tissue Morphologic Changes of Chang-Sheng-Chuan Green Brick Tea Before ad After Fermentation

[Objective] The aim was to understand the change of fermentation pro- cess of Chang-sheng-chuan green brick tea and analyze the changes in the con- tents of structure components of tea leaves before and after fermentation. [Method] Ten tea leaves before and after fermentation were chosen. The tea leaves sections were made using paraffin microtomy, PAS staining, and observed under light mi- croscopy. Through image analysis for the tea leaves, we compared the changes on the areas of the cellulose and colloid in cell before and after pile-fermentation. At the same time, the tea leaves were observed under transmission electron micro- scope. [Result] The results showed that the pile-fermentation process caused the tea leaves tissue to become loose, and expanded the cell space. Besides, the cell wall of tea leaves was obviously thinning, and even breaking which composed of cellulose. Image analysis showed that the leaf fiber composition reduced significant- ly, with a corresponding increase of yellow colloid in cell. Under observation of transmission electron microscope, there were large amounts of fungi located in the space between the colloid and the cell wall of the tea leaves after pile-fermentation. [Conclusion] The fermentation of Green brick tea is the process of microbial bio- transformation of tea, which is dominated by microbe and consumed the cellulose components of tea leaves.

Fermentation characteristics and probiotic activity of a purified fraction of polysaccharides from Fuzhuan brick tea

Polysaccharides from Fuzhuan brick tea(FBTPS),one of most important bioactive components in tea,showed various health-promoting functions.Our previous work demonstrated that the crude FBTPS(CFBTPS)could modulate the gut microbiota.However,which purified fraction in CFBTPS contributing to the modulation of gut microbiota remains unclear.Thus,the fermentation characteristics and probiotic activity of a purified fraction(FBTPS-2-1)of CFBTPS were evaluated in this work.The results showed that gut microbiota could utilize FBTPS-2-1 to produce short-chain fatty acids including acetic,propionic,n-butyric and n-valeric acids.FBTPS-2-1 could modulate the structure and metabolic pathways of gut microbiota.FBTPS-2-1 could increase the health-promoting gut microbiota such as Prevotellaceae and Bifidobacteriaceae,and decreased the harmful bacteria such as Enterobacteriaceae and Fusobacteriaceae.The results of metagenomics showed that Prevotella copri and Megamonas funiformis were the dominant bacteria after fermentation of FBTPS-2-1.Furthermore,FBTPS-2-1 could regulate the biosynthesis and metabolism pathways of gut microbiota.Thus,the enrichment of food with FBTPS-2-1 is expected as a potential strategy for promoting human health due to modulation of gut microbiota.

The role of cholesterol in modifying the lipid-lowering effects of Fuzhuan brick-tea in Caenorhabditis elegans via SBP-1/SREBP

Fuzhuan brick-tea(FZT)has long been consumed for its supposed weight loss and lipid-lowering benefi ts.In this study,we show that the regulation of fat storage in Caenorhabditis elegans from a water extract of FZT was affected by cholesterol levels.We found that FZT signifi cantly decreased fat storage under normal cholesterol levels or in a cholesterol-free diet,while lipid accumulation was increased for a high cholesterol diet.Moreover,this mechanism may involve the conserved sterol regulatory element-binding protein(SREBP)/mediator-15(MDT-15)signaling pathway and the nuclear hormone receptor NHR-80.In addition,lipid synthesis-related genes inhibited by FZT were partially affected by a cholesterol-free diet.Thus,our fi ndings suggested that the potential lipid-lowering effects of FZT may depend on the cholesterol level,which may help to improve the consumption of FZT.

Fungi with potential probiotic properties isolated from Fuzhuan brick tea

Several of the fungal species associated with Fuzhuan brick tea(FBT)are considered as potential probiotics,but few studies have investigated the probiotic properties of these fungi.Here,we isolated 18 fungal strains from two types of FBT and identified these strains based on internal transcribed spacer(ITS)fragment sequence similarity to reference strains(sequence similarity>98%).Of the 18 strains,10 tolerated simulated human digestive conditions for sufficient periods in vitro:pH 2-3,0.3%-0.5%(m/V)bile salts,and artificial gastrointestinal juices.We then measured the antimicrobial activity of the remaining 10 strains against 5 enteropathogenic bacteria and tested the bacteriostatic effects of the thalli and fermentation broth extracts.Of the 6 strains with strong bacteriostatic effects,we eliminated Eurotium cristatum S-9 due to its low hydrophobicity of(26.12±0.35)%.Finally,2 exhibited good adhesion abilities to human cells(>100%).Notably,2 strains can survive in vivo,because they can be isolated from C57BL/6 mice feces.Thus,2 strains,Aspergillus cristatus H-1 and A.cristatus H-5,are herein identified as promising candidate probiotic strains.It may be put forward a novel research focus on evaluating potential probiotic fungi from FBT.

Water Bath Extraction Optimization of Polyphenols from Qing Brick Tea and Raw Material Selection for Tea Polyphenol Extraction

In this paper,single-factor experiments and orthogonal experiment were conducted to optimize the water bath extraction of polyphenols from Qing Brick Tea,and the optimal extraction conditions obtained were as follows:solvent of 50%ethanol,solid/liquid ratio of 1∶30,temperature of 80℃,and time of 6 min.Under the optimal water bath extraction conditions,polyphenols in fresh tea leaves,fresh tea petioles,fresh tea blades,finished brick tea,finished tea petioles,finished tea blades,tea dregs after brewing and tea dregs after boiling were extracted,respectively.It was found that the quality fraction of polyphenols extracted from fresh tea leaves was the highest,with the best extraction effect.The extraction effect of leaf blades was better than that of leaf petioles,and the extraction effect of tea dregs after brewing was better than that of tea dregs after boiling.

The characteristics of dissolution of fluoride and aluminum from brick tea

Four experiments have been done on the influence of times of infusion, temperature, time and ratio of tea to water on the dissolving characteristics of fluoride and aluminum in brick tea. According to the results, the behaviors of F and Al which found their way into tea liquor were analyzed and the conclusions have been drawn: the dissolution of F and Al is not synchronous and after the elements find their way into tea liquor respectively, they will be reset to form complexes of F and Al.

Fuzhuan brick tea affects obesity process by modulating gut microbiota

The effect of Fuzhuan brick tea(FBT)on metabolism in obese mice is mediated by regulation of N-methyltransferase by aryl hydrocarbon receptor.The expression of the phosphatidylethanolamine N-methyltransferase gene is regulated by many transcription factors,and those specific to this effect need further investigation.Experimental animal studies have been designed to observe the effects of a single drug or the sequential effects of drugs.A washout period should be included if different drugs(e.g.,antibiotics and FBT)are given to avoid or reduce additive effects or synergy.Currently,most experimental studies performed in mice used only male animals.However,experience has revealed that the results of using only male mice are very likely to have sex differences.

Hypoglycemic effects of black brick tea with fungal growth in hyperglycemic mice model

Dark tea(containing Eurotium cristatum)and black tea have hypoglycemic effects.The black brick tea with fungal growth is obtained from black tea by adding E.cristatum,followed by steaming,pressing,fungal growth,and drying.However,the hypoglycemic effects of black brick tea are still unexplored.Here,we used black brick tea with fungal growth and black tea as raw materials to study their hypoglycemic effects in a hyperglycemic mice model.Both these types of black tea could lower the content of blood glucose and increase the content of hepatic glycogen by upregulating the proteins and m RNA expression of phosphatidylinositol-4,5-bisphosphate3-kinase,glycogen synthase,protein kinase B and phosphoinositidedependent protein kinase-1 and downregulating the protein and m RNA expression of glycogen synthase kinase 3β.These regulatory steps were followed by high activities of glutathione peroxidase and superoxide dismutase and low content of malondialdehyde.These teas can promote blood glucose transport and absorption by upregulating the protein and m RNA expression of insulin receptor substrate-1 and glucose transporter-2 and stimulate glycolysis by upregulating the protein and m RNA expression of 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 2.Our study suggests that the black brick tea was more effective than the black tea in terms of hypoglycemic.

Fluoride in Tea and Its Risk Assessment

Tea plant absorbs from soil a large amount of fluorine(F) which is accumulated in leaf,resulting in elevated F concentration in tea.It is a controversial topic whether the fluoride in tea is associated with fluorosis.The research advances in F variation of various kinds of tea,factors influencing F level in tea and the associated health risk assessment were reviewed in the present paper.The F level in tea increases with the maturity of the tea leaf.Brick tea had a high F content because it was prepared using mature shoots and old tea leaves as raw material.Some low grade UK supermarket economy teas contained elevated F comparable to the Chinese brick tea.Tea F level is also affected by tea cultivar,soil condition,tea processing method and tea infusion preparation method.

湖南与陕西茯砖茶的化学多样性

为探究湖南和陕西两产地茯砖茶的代谢物种类多样性以及比较分析两者代谢物轮廓,同时寻找茶鲜叶与茯砖茶化学成分的区别,进一步考察茯砖茶中来自真菌的代谢产物。本研究采用液相色谱-串联质谱仪和基于特征物的分子网络等方法,对茶鲜叶样本、湖南和陕西两个产地的茯砖茶及其分离真菌进行代谢组学研究。结果表明:在代谢物种类多样性和代谢物轮廓方面,湖南与陕西茯砖茶之间不存在显著差异。另外,茶鲜叶经历加工成为茯砖茶的过程中,代谢物种类多样性极显著提高,黄烷-3-醇类、嘌呤生物碱类、大部分氨基酸及其衍生物类的含量降低,溶血磷脂酰胆碱和脂肪酸的含量增加,且出现了种类丰富的真菌代谢物。典型的真菌代谢物包括异戊烯基环二肽类、异戊烯基苯甲醛类等化合物,它们的存在丰富了茯砖茶代谢物的多样性。

冲泡条件对灵芝茯茶茶汤品质的影响

为探究冲泡条件对灵芝茯茶茶汤品质的影响,以灵芝茯茶为原料,利用单因素试验研究茶水比、冲泡温度、冲泡时间对茶汤风味的影响,设计三因素三水平正交试验,结合感官评价及茶汤内8种主要风味成分含量,对其进行主成分分析,筛选出灵芝茯茶的最佳冲泡条件。结果表明,茶水比、冲泡温度和冲泡时间均对灵芝茯茶茶汤的风味有明显影响。通过主成分分析将11个指标简化为2个主成分,其累积方差贡献率为86.939%,综合评价结果显示,在茶水比3∶150(g/mL)、冲泡温度100℃、冲泡时间3 min条件下,茶汤的综合得分最高,为灵芝茯茶的最佳冲泡条件。

陈年茯砖茶对高脂血症小鼠的调脂作用

为探究不同年份茯砖茶对高脂饮食诱导的肥胖及高脂血症的预防效果,以C57BL/6J小鼠为研究对象,以陈化1年和10年的茯砖茶为代表性茶样,设置了正常饮食(ND)组,高脂饮食(HFD)组,以及陈化1年茯砖茶干预(1Y)组和陈化10年茯砖茶干预(10Y)组。生物活性成分分析发现,陈化10年茯砖茶中的茶褐素、可溶性糖含量明显增加,而多酚和儿茶素单体明显下降。动物实验结果表明,与HFD组相比,陈化1年和陈化10年的茯砖茶能够有效降低小鼠肝脏和血清脂质水平、体重增长、器官系数和脂肪组织重量,且陈化10年的茯砖茶具有相对显著的效果。小鼠肝脏和脂肪组织切片显示,补充茯砖茶可以减少肝脏中脂滴的形成和空泡的出现,同时抑制了脂肪细胞的膨大。此外,补充茯砖茶能够改善高脂饮食导致的炎症和肝脏氧化应激,与陈化1年的茯砖茶相比,陈化10年的茯砖茶显著降低了炎症因子IL-6和TNF-α水平以及肝损伤指标AST和ALT活力,同时显著上调了肝脏GSH含量(P<0.05)。这可能是由于陈化10年茯砖茶丰富的茶褐素以及与其他活性成分共同作用的结果。

不同原料和工艺对岩茯茶中真菌群落的影响

目的 探明岩茯茶的制作原料和工艺对其真菌群落的影响。方法 本研究以4种武夷岩茶作为原料,分别经过传统茯砖茶工艺、高压汽蒸渥堆、微生物菌剂和复合处理等工艺进行加工。通过真菌ITS2区域测序技术,对不同原料和工艺处理下岩茯茶的真菌群落结构进行表征。结果 通过ITS测序表明,岩茯茶样品中共检测出3个门、12个纲、24个目、36个科、43个属和51个种,其中子囊菌门为绝对优势门、散囊菌属为绝对优势属;在大部分样品中散囊菌属的相对丰度均高达97%以上,是岩茯茶中的优势菌属;不同原料和工艺会对岩茯茶中真菌群落的数量变化产生一定的影响,对优势菌群—散囊菌属的影响不大,而对其他真菌群落有显著影响,从而影响茶叶的感官品质。结论 不同原料和工艺影响真菌群落的共同作用,促进了茯砖茶中的物质转变。本研究为今后岩茯茶生产的原料和工艺选择提供了参考,并为砖茶类产品中的微生物群落结构提供了新见解。

茯砖茶感官特征分析及其产地判别模型构建研究

为客观准确地评价不同产地茯砖茶感官特征品质,结合感官审评、化学组分检测、化学计量学等研究茯砖茶感官品质特征及不同产地茯砖茶判别模型构建。结果表明:湖南、浙江、陕西等19个茯砖茶因原料物质基础的不同其感官品质有非常明显的差异。其中,茯砖茶滋味得分(taste score, TS)与咖啡碱(caffeine, CAF)、水浸出物(water leachate, WL)、儿茶素(catechin, CAT)和表儿茶素(epicatechin, EC)呈现出显著相关性,其相关系数(P<0.05)分别为0.81、0.62、0.55、0.50。同时,基于化学组分的主成分(PCA)表明,前4个主成分的累计方差贡献率为79.48%,并以前4个主成分的线性回归方程和贡献率构建了茯砖茶感官品质综合评价模型与产地判别模型。正交偏最小二乘法判别分析(OPLA-DA)显示,19个不同产地的茯砖茶样品被明显地划分为3组,评价模型对不同产地茯砖茶识别度较高。采用交叉验证法对模型进行验证,模型对自变量的拟合指数(R~2X)为0.879,对因变量的拟合指数(R~2Y)为0.992,预测指数(Q^(2))为0.53。经OPLS-DA共识别出6种预测变量重要性投影(VIP)值大于1的差异指标,其中茶多酚(tea polyphenols, TPP)、可溶性糖(soluble sugar, SS)、CAF、WL为茯砖茶感官特征标志性差异品质成分。结果表明,应用感官审评、化学组分检测、化学计量学等方法可以实现茯砖茶感官特征及其不同产地茯砖茶的快速、准确判别,同时也为茯砖茶感官特征及其不同产地判别提供一种新的参考方法。

色谱柱极性对茯砖茶挥发性成分分析的影响

为全面了解色谱柱极性对茯砖茶挥发性成分分析的影响,比较了3种不同极性的色谱柱(极性色谱柱HP-INNOWAX、中性色谱柱DB-35MS、非极性色谱柱HP-5MS)对茯砖茶挥发性成分分离鉴定效果的差异。结果表明,3种不同极性的色谱柱共鉴定出169种挥发性成分,其中共有挥发性成分29种。HP-INNOWAX、DB-35MS、HP-5MS分别鉴定出77、66、116种,其中特有挥发性成分分别为32、12、64种。从鉴定的化合物的质量分数来看,HP-INNOWAX分离得到的化合物质量分数最高,占化合物总质量的43%,DB-35MS其次(31%),HP-5MS最低(26%)。3种不同极性的色谱柱在茯砖茶挥发性成分分析中各有优势,极性色谱柱HPINNOWAX对醇类物质的分离效果较好,中性色谱柱DB-35MS对酮类物质的分离效果较好,非极性色谱柱HP-5MS对碳氢类、酮类和醛类物质的分离效果较好。通过不同极性的色谱柱对茯砖茶的挥发性成分分析,可以更全面地了解其香气组成,从而揭示茯砖茶独特的风味特征。

中国典型砖形黑茶非挥发物的代谢组学分析

为探究我国典型砖形黑茶代谢物轮廓的规律,以及砖形黑茶与黑茶真菌在代谢物种类方面的关系,本研究利用基于液相色谱-质谱联用的非靶向代谢组学和基于特征物信息的质谱分子网络技术,对我国典型的砖形黑茶(湖北青砖茶、四川康砖茶、湖南的黑砖茶、花砖茶和茯砖茶、陕西的茯砖茶)以及茶鲜叶和分离自黑茶的多种真菌进行代谢组学分析。结果表明,砖形黑茶的非挥发性代谢物轮廓更倾向于按照生产地区进行分类,一组是来自湖南和陕西的砖形黑茶,而另一组是来自四川和湖北的砖形黑茶;决定其代谢物轮廓分组的最主要因素是砖茶含梗率,来自四川和湖北的砖形黑茶含梗率明显高于另一组;造成两组砖形黑茶轮廓差异的主要原因是湖南和陕西的砖形黑茶中有更高含量的黄烷-3-醇类和大部分氨基酸及其衍生物等代谢物;针对砖形黑茶和真菌代谢物的分子网络分析发现,在砖形黑茶中,尤其是在康砖茶中广泛分布着源自真菌的线性和环状二肽;在茯砖茶中有着结构种类丰富的异戊烯基二酮哌嗪类化合物,这类化合物来自于冠突散囊菌,因此,真菌为砖形黑茶贡献了种类丰富的代谢物。本实验结果可为全面了解和认识我国典型砖形黑茶的化学物质基础提供理论参考。

六堡砖茶多糖制备及其免疫调节活性

目的:优化六堡砖茶多糖提取工艺,并进一步研究其免疫调节作用及其可能的调节机制。方法:采用单因素实验探究提取温度、料液比及乙醇浓度对茶多糖得率的影响,在此基础上与响应面试验相结合,对茶多糖提取工艺进行了优化。通过测定六堡砖茶多糖对RAW264.7细胞的吞噬能力及NO释放量,检测核因子κB(Nuclear factor-κB,NF-κB)和AMP依赖的蛋白激酶(AMP-dependent protein kinase,AMPK)信号通路相关基因及蛋白表达,评价纯化后的茶多糖的体外免疫调节活性。结果:六堡砖茶多糖的最佳提取工艺为:提取温度91.11℃,料液比1:15.45(g/mL),乙醇浓度82.84%(v/v)。在此条件下,茶多糖得率为8.62%。细胞实验显示六堡砖茶多糖可显著增强RAW264.7细胞的吞噬能力及NO释放量(P<0.05),显著激活NF-κB和AMPK信号通路(P<0.05),显著上调诱导型一氧化氮合成酶(Inducible nitric oxide synthase,iNOS)、肿瘤坏死因子-α(Tumor necrosis factor-α,TNF-α)、白细胞介素-6(Interleukin-6,IL-6)、白细胞介素-1β(Interleukin-1β,IL-1β)的mRNA表达水平(P<0.05)。其中,高剂量茶多糖效果更佳。结论:通过优化提取温度、料液比及乙醇浓度条件,可有效提高六堡砖茶多糖得率,并可通过激活NF-кB/AMPK通路发挥免疫调节作用。该研究结果为六堡砖茶多糖活性深入探究和应用提供了研究基础。