The modulatory effect of oolong tea polyphenols on intestinal flora and hypothalamus gene expression in a circadian rhythm disturbance mouse model

The interaction between host circadian rhythm and gut microbes through the gut-brain axis provides new clues for tea polyphenols to improve host health.Our present research showed that oolong tea polyphenols(OTP)improved the structural disorder of the intestinal flora caused by continuous darkness,thereby modulating the production of metabolites related to pyruvate metabolism,glycolysis/gluconeogenesis,and tryptophan metabolism to alleviate the steady-state imbalance.After fecal microbiota transplantation from the OTP group,the single-cell transcriptomic analysis revealed that OTP significantly increased the number of hypothalamus cell clusters,up-regulated the number of astrocytes and fibroblasts,and enhanced the expression of circadian rhythm genes Cry2,Per3,Bhlhe41,Nr1d1,Nr1d2,Dbp and Rorb in hypothalamic cells.Our results confirmed that OTP can actively improve the intestinal environmental state as well as internal/peripheral circadian rhythm disorders and cognitive impairment,with potential prebiotic functional characteristics to notably contribute to host health.

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.

Multifunctional health-promoting effects of oolong tea and its products

Oolong tea,partially fermented from Camellia sinensis leaves,exhibits significant antioxidative,anti-inflammatory,and anti-cancer activities as indicated in several in vitro and in vivo studies.However,studies on health promoting effects of oolong tea and its characteristic compounds are limited.The potential efficacy of bioactives derived from oolong tea and their roles as promising anticancer agents,their cardio-protective benefits during hypoxic conditions,effects in treating allergic disorders,potential prebiotic activities,improvement of blood lipid status in human beings,effectivity as oral hypoglycemic agent in the treatment of type 2 diabetes,and their potentials to reduce the risk of obesity have been discussed in this review.These promising studies mainly gained from animal studies might broaden the consumption and usage of the phenolic-enriched oolong tea and its products in food and pharmaceutical industries.However,potential health beneficial effects of oolong tea in humans should be further complemented by large-sized,randomized double-blind and placebo-controlled trials to consolidate potential therapeutic applications.

Exploration of Factors Influencing Oolong Quality and Control Technology in Anxi County

In the research, harmful substances to oolong in Anxi were introduced and production environment, agricultural residual, heavy metal and rare earth ele-ments of oolong in Anxi were analyzed. Furthermore, the factors influencing oolong quality were explored, and the control measures for guaranteeing oolong safety were proposed.

Effect of Different Drying Methods on the Volatile Compounds Jinmudan Oolong Tea

Jinmudan,a new tea variety from Fujian Province has an excellent quality with a unique aroma like magnolia frogrance.To monitor the changes in the tea volatile compounds during the Jinmudan Oolong tea manufacturing(drying) process,the volatiles of tea samples were extracted and analyzed.Characteristic volatile compounds in Jinmudan Oolong tea were nerolidol,α-farnesene,linolenic acid,palmitic acid,indole,phenylacetaldehyde,cisjasmone,β-phenylethanol,etc.The content of nerolidol was the highest in four tested samples.The composition of the volatile compounds in microwave drying sample was simple,but its concentration was high,in which the main volatile compounds were alcohols and esters.The processing with combination of traditional drying craft and modern aroma-improvement technique could obviously improve the tea aroma,especially in level of epoxy linalool and jasmine lactone.

A Study on Effects of Turn-over Technology on the Quality of Jinmudan Oolong Tea

This paper reported the effect of oolong tea processing procedure of turn-over on quality of the Jinmudan Oolong tea,including taste components and volatile compounds.The content of the water extractable solids was gradually increased,but the content of amino acid decreased and then increased,and the content of the soluble sugar and tea polyphenols increased after the first turn-over processing.The major volatiles of the three tested Jinmudan Oolong tea samples were nerolidolcistrans,α-farnesene,palmitic acid,indole and 9,12,15-octadecatrienoicacid and methyl ester.The sensory evaluation results showed that an appropriate increase in the number of turn-over was helpful to quality of the Jinmudan Oolong tea.

Beneficial Effects of Oolong Tea Consumption on Diet-induced Overweight and Obese Subjects

Objective:To determine the anti-obesity effects of oolong tea on diet-induced overweight or obesity.Methods:A total of 8 g of oolong tea a day for 6 weeks was ingested by 102 diet-induced overweight or obese subjects.The body fat level of the subjects was determined at the same time by taking body weight, height and waist measurements.The thickness of the subcutaneous fat layer was also determined on the abdomen 3 cm to the right of the navel by the ultrasonic echo method.On the other hand,effects of oolong...

Effects of fermentation time on phenolic composition, antioxidant and antimicrobial activities of green, oolong, and black teas

In this study, it was aimed to investigate the effect of fermentation degree on total phenolic content, individual catechins, gallic acid, theaflavins, caffeine content, antioxidant and antimicrobial activity in teas. Green tea, black tea and oolong tea (partially oxidized 7 different degrees) were produced from the same cultivar of tea leaves harvested in first shooting period. The higher degree of fermentation was resulted in higher theaflavins, however in lower individual catechins and total phenolic content. Standard catechins gradually decreased with extended fermentation duration and epigallocatechin gallate decreased 87% from green tea to oolong to black tea. Higher antioxidant activity was observed in green and lower fermented oolong teas. There were significant (p<0.01) positive correlations (r2>0.9) between DPPH, ABTS assays and total phenolic content, catechin, epigallocatechin gallate, epicatechin, epicatechin gallate and total catechins. Significant (p<0.05), positive correlations (r2>0.7) were also observed between ORAC and those catechins. Moreover, the tea samples especially green tea showed antibacterial effects against three of the tested pathogenic bacteria Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Pseudomonas aeruginosa ATCC 27853 and antifungal effects against Candida albicans ATCC 10231. However, no antimicrobial activity was detected against Escherichia coli.

Development and experiment of the mechanism for oolong tea stirring motion based on the manual stirring characteristics analysis

In this study,the motion characteristics of manual stirring were analyzed to achieve the goal of realizing a highquality mechanized imitation of manual stirring for oolong tea.A test bench for collecting the motion characteristics of manual stirring was designed,and the standard manual stirring motion characteristic curve was obtained.According to the requirements of the stirring motion characteristics,a variable-speed and variable-amplitude stirring mechanism was proposed,the kinematics model and reverse design model of the stirring mechanism were established,auxiliary analysis and design software were written,and the non-circular gear pitch curve and cam profile curve were obtained.A three-dimensional model of the stirring machine was established,a virtual prototype of the stirring machine was built,and the simulation experiment was completed by using the ADAMS software.A prototype of the stirring machine was developed,and the stirring experiment was conducted on the prototype.The maximum deviation of the pitch angle is 2.8772°,and the maximum deviation of the roll angle is 1.5948°according to the analysis and comparison of the actual curve data and the theoretical data curve.The experimental results showed that the simulation angle curve and the actual angle curve were consistent with the theoretical standard manual stirring motion characteristic curve,which verified the correctness of the design and modeling of the stirring mechanism.The tea was mechanically stirred by the stirring mechanism to achieve the desired stirring effect,which verified the feasibility of the stirring machine.

Characterization of volatile composition,aroma-active compounds and phenolic profile of Qingxin oolong tea with different roasting degrees

Due to the premium flavor,Qingxin oolong tea(QOT),which is grown and produced in Taiwan,is widely appreciated.Roasting is a crucial process for shaping its flavor.However,the effect of roasting on the aroma and taste of QOT was not fully understood.In this study,the volatile composition,aroma-active compounds and phenolic profile of QOT with different roasting degrees,including the unroasted(UR),the medium roasted(MR)and the heavy roasted(HR)were analyzed.As revealed by headspace solid phase microextraction gas chromatography-mass spectrometry(HS-SPME-GC-MS)and multivariate statistical analyses,UR and MR demonstrated similar volatile profiles,while heavy roasting changed the volatile composition greatly.Multiple nitrogen-containing compounds,such as 3,5-diethyl-2-methylpyrazine and 2-ethyl-3,5-dimethylpyrazine,were uniquely found in heavy roasted samples,which can be ascribed to the extensive Maillard reaction.Moreover,eight compounds were identified and verified as key aroma-active compounds by using gas chromatography-olfactometry-mass spectrometry(GC-O-MS),aroma recombination and omission experiments.The aldehydes and alcohols,such as linalool,benzeneacetaldehyde andα-farnesene,with a floral scent were the dominant aroma-active compounds in UR and MR,while 2-ethyl-3,5-dimethylpyrazine and 3,5-diethyl-2-methylpyrazine with a roasted scent were the main aroma-active compounds in HR.Furthermore,as revealed by ultra-high performance liquid chromatography and Orbitrap high resolution mass spectrometry(UHPLC-Q-Orbitrap-MS),flavanols and phenolic acids were significantly lower in abundance in UR and MR as compared to those in HR,whereas flavonols were less affected by roasting.These findings provide useful information for understanding the flavor characteristics of this popular oolong tea for the first time.

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。

3种生物样本透射电镜OTE染色效果

为探究乌龙茶提取物(OTE)取代醋酸双氧铀(UA)在畜牧生物样本透射电镜制样中的染色效果,选取畜牧业中3种常见的生物样本即山羊坐骨神经、酵母菌及苜蓿叶片组织为测试对象,经多聚甲醛-戊二醛PBS混合溶液预固定后制备超薄切片,采用OTE染色,再用透射电镜观察样品反差情况,并与传统UA染色法进行比较。结果显示3种生物样品的OTE单染组和双染组(OTE-Pb双染)在反差对比度、图像清晰度、结构辨识度等方面均与对应的UA单染组和双染组(UA-Pb双染)相当,甚至更佳。结果说明OTE染色在畜牧生物类样品透射电镜制样中的染色效果稳定,反差良好,而且比常规使用的UA安全性高,具有更广阔的应用前景。

茶树新品系‘福茗2号’区域试验报告

【目的】选育早生、高产、高香茶树新品种,满足消费需求的多样化。【方法】以‘黄棪’为对照,在福建福安、松溪、福州3个区试点对‘福茗2号’新品系的种植成活率、物候期(一芽一叶、一芽二叶和一芽三叶期)、鲜叶产量、制茶品质、抗性等方面进行为期6年(2016—2021年)的茶树品种区域试验。【结果】‘福茗2号’新品系种植成活率高,达89%以上;物候期比对照早1~2 d;鲜叶产量比对照高5%左右;制乌龙茶品质比对照高出0.5~1.1分;耐寒、耐旱性强,茶炭疽病和茶小绿叶蝉抗性均表现为抗。【结论】‘福茗2号’是一个早生、高产、优质、高抗的乌龙茶新品种,适宜在福建福安、松溪、福州及相似乌龙茶地区种植和推广应用。

乌龙茶叶粉尘爆炸特性实验研究

选取某茶叶公司的乌龙茶叶粉尘为研究对象,用激光粒度分析仪对其粒径分布进行表征.在粉尘层着火温度实验装置、高德伯尔格-格润瓦尔德炉、哈特曼管爆炸实验装置、Siwek 20 L球形爆炸系统中测试研究了粉尘着火敏感度及爆炸猛度.实验结果表明:粉尘层的最低着火温度为250℃,粉尘云的最低着火温度为510℃,最小点火能>1000 mJ,爆炸下限为120 g/m^(3),粉尘云的最大爆炸压力达0.82 MPa,最大压力上升速率达63.0028 MPa/s,爆炸指数达17.1 MPa·m/s,乌龙茶叶粉尘爆炸等级为St-1.借助热重分析和工业分析,对其爆炸特性进行了理论分析.研究结果对了解茶叶粉尘爆炸危险性、加工车间的安全管理以及防爆设计具有一定的参考价值.

响应面法优化乌龙茶提取茶多糖的工艺研究

以乌龙茶为原料,选用回流法提取茶多糖,根据Plackett-Burman实验设计考察提取温度、提取时间、提取次数、料液比等多种因素对茶多糖提取率的影响;在单因素实验基础上,运用Box-Behnken实验设计进行响应面剖析.实验结果显示,当提取温度100℃、提取时长80 min、料液比1∶50时,乌龙茶茶多糖的提取率显著增加,得率是6.13%.对最佳提取工艺开展验证,结果显示实测均值与模型估计值相近,表明该提取工艺平稳可行.

乌龙茶茶树品种制白茶的风味特征及特征组分分析

为探究乌龙茶品种所制白茶与传统白茶的风味品质差异,以紫玫瑰等8种乌龙茶品种所制白茶为研究对象,以福鼎大毫茶所制传统白茶为对照,结合感官审评、生化检测和多元统计分析手段进行分析。结果表明:乌龙茶品种所制白茶的外形、汤色较传统白茶暗,观感欠佳;而滋味和香气优于传统白茶。生化成分检测分析发现电导率、pH值、可溶性糖含量、游离氨基酸含量、没食子儿茶素没食子酸酯含量以及表没食子儿茶素没食子酸酯含量的差异是导致传统白茶与乌龙茶品种所制白茶滋味迥异的重要因素。挥发性物质检测表明:反式-2-壬醛、顺-3-壬烯-1-醇、棕榈酸甲酯、芳樟醇、亚油酸甲酯、柏木脑、甲酸香叶酯、苯乙醇、橙花醇、水杨酸甲酯、邻苯二甲酸二丁酯和植酮是影响传统白茶与乌龙茶品种所制白茶香型呈现的关键差异香气成分。本研究揭示了乌龙茶品种所制白茶与传统白茶间的风味品质差异,证明了乌龙茶品种具有开发花香型白茶的潜力,可为白茶风味进一步多元化提供理论参考。

基于SBSE-GC-O-MS技术的3个代表性乌龙茶品种关键香气成分分析

为探究3个代表性乌龙茶品种关键香气成分,采用搅拌棒吸附萃取结合气相色谱-嗅闻-质谱(gas chromatography-olfactory-mass spectrometry,GC-O-MS)联用技术对黄旦、铁观音、金观音3个代表性乌龙茶品种关键香气成分进行鉴定和描述,结合香气活性值(odor activity value,OAV)、香气特征影响值和感官审评进行对比分析。感官审评表明,3个品种乌龙茶各表现出明显的品种特征香气,黄旦花香显,略带奶香,铁观音花香浓郁,金观音具甜果香,略带木质香。结合OAV及GC-O-MS鉴定结果表明,香叶醇、植醇、茉莉酸甲酯、反式-橙花叔醇、2-壬酮、苯乙醇等物质是黄旦的关键香气成分,赋予黄旦花香清高、奶香显的香气特征;铁观音中的芳樟醇、3,5-辛二烯-2-酮、氧化芳樟醇、顺式茉莉酮、脱氢芳樟醇、α-松油醇等物质呈多元性的花香,与其品种特征香气密切相关;金观音中的关键香气成分包括芳樟醇、藏花醛、香叶基丙酮、顺式茉莉酮、异丁子香酚等物质,是形成其甜果香与木质香品种特征香气的关键物质。

不同烘焙程度‘春闺’闽北乌龙茶风味品质分析

采用感官审评、生化分析、超高效液相色谱三重四极杆串联质谱(UPLC-QqQ-MS)及顶空固相微萃取法结合气相色谱-飞行时间质谱联用技术(HS-SPME-GC-TOF-MS)对不同烘焙程度‘春闺’闽北乌龙茶进行检测分析,通过建立偏最小二乘判别分析模型、趋势模型探究其感官品质、常规生化成分、儿茶素组分、氨基酸组分及挥发性物质等方面的差异。结果表明:轻火‘春闺’感官审评总分为(91.3~93.65),略低于中火‘春闺’(93.6~94.15);生化成分中,轻火‘春闺’的氨基酸含量显著高于中火(P<0.05),中火‘春闺’的的茶黄素、茶褐素含量及酚氨比显著高于轻火火‘春闺’(P<0.05);对氨基酸组分进行TAV值计算得到,轻火‘春闺’主要呈味贡献氨基酸为半胱氨酸、天冬氨酸、谷氨酸及茶氨酸,中火‘春闺’为半胱氨酸、谷氨酸及茶氨酸;在主要差异挥发性物质中,轻火‘春闺’的橙花叔醇、吲哚、α-法尼烯及顺-茉莉酮等花香类挥发性物质含量显著高于中火‘春闺’(P<0.05);中火‘春闺’的顺-芳樟醇氧化物、茶吡咯、2,5-二甲基吡嗪、糠醛、脱氢-β-紫罗兰酮及二氢猕猴桃内酯含量显著高于轻火‘春闺’(P<0.05)。‘春闺’闽北乌龙茶适合采用中火烘焙工艺,其滋味醇爽浓厚有花香,香气类型呈现为花香馥郁,综合品质较优。本研究为‘春闺’闽北乌龙茶配套加工工艺和风味品质提供一定的理论依据。

焙火工艺对白芽奇兰茶叶挥发性香气成分的影响

采用顶空固相微萃取-气相色谱-质谱联用和香气活性值分析,研究特色乌龙茶白芽奇兰茶叶焙火前后香气成分的变化。结果表明,焙火前后白芽奇兰茶叶香气成分类别和含量发生了显著变化。焙火前白芽奇兰茶叶的主要香气贡献成分包括香叶醇、脱氢芳樟醇、顺式-香柠檬烯、苯乙醇、苯乙醛、顺式-茉莉酮和香叶基丙酮。焙火后白芽奇兰茶叶的主要香气贡献成分包括香叶醇、脱氢芳樟醇、顺式-茉莉酮、香叶基丙酮、顺式-香柠檬烯、苯乙醇、苯乙醛、藏红花醛、反式-2-癸烯醛、茶香酮、顺式-香柠檬烯、波斯菊萜、顺式-芳樟醇氧化物和2-戊基呋喃。白芽奇兰茶叶焙火后香气变化是由于低沸点物质挥发、α-紫罗兰酮转化、糖苷热分解、醇类物质氧化、脂质过氧化分解、萜醇类物质转化等,导致茶香酮、顺式-芳樟醇氧化物、2-戊基呋喃等关键香气成分的产生,藏红花醛、反式-2-癸烯醛和波斯菊萜的含量大幅度增加。本研究阐明了焙火工艺对白芽奇兰茶叶香气成分的影响,发现焙火工艺增添了香气活性成分从而改变乌龙茶的香气特征,且首次发现焙火工艺会导致茶香酮这种关键香气成分产生,对深入了解焙火工序对白芽奇兰茶叶和其他乌龙茶香气成分的影响提供了参考。

响应面法优化乌龙茶碳酸饮料配方

目的探究乌龙茶碳酸饮料的最佳配方。方法以清香型铁观音、白砂糖和柠檬酸为主要原料,制作乌龙茶碳酸饮料。采用单因素试验、响应面试验,以感官审评评分为判断依据,分析不同茶浸提液、白砂糖和柠檬酸添加量对乌龙茶碳酸饮料品质的影响和最佳配方。结果乌龙茶碳酸饮料的最佳配方为:茶浸提液含量40.00%、白砂糖添加量12.50%、柠檬酸添加量0.25%。此配方制成的乌龙茶碳酸饮料感官评分为(86.75±1.76)分,汤色清澈,茶味适中,酸甜平衡。其pH为2.74,茶多酚含量为320.95 mg/kg,游离氨基酸含量为48.80 mg/L,总酸含量为2.36 g/L,可溶性固形物含量为13.50%,有茶碳酸饮料所需具备的品质。结论此产品在碳酸饮料的基础上有着乌龙茶独有的香气和滋味。乌龙茶碳酸饮料的制作在将茶叶应用扩大的同时也为茶汽水的研究提供数据支撑。