Discrimination of teas based on total luminescence spectroscopy and pattern recognition

This paper reports on the application of total luminescence spectroscopy to discriminate between seven different types of tea: four bottled liquid Japanese teas (oolong, green, houji and black teas) and three leaf teas (Kenya, Assam and Ceylon teas). Total luminescence spectra were recorded by measuring the emission spectra in the range 300–700 nm at excitation wavelengths from 250 to 590 nm. Discrimination of teas based on their spectral data was performed by principal component analysis, a common chemometric method used for data reduction and visualisation. The results demonstrate the ability of fluorescence techniques to differentiate between green tea (unfermented), black tea (fermented) and oolong tea (partially fermented). Copyright © 2006 Society of Chemical Industry     

Effect of shooting period, region of growth and processing method on the Fe and Mn content of tea determined by X-ray fluorescence

X-ray fluorescence (XRF) is an effective technique for qualitative and quantitative analysis of minerals in various agricultural products. Simplicity, high throughput and the possibility of automation make it useful for screening large numbers of samples. Samples of 138 fresh green, black tea and residue of this black tea after brewing were obtained from the Eastern Black Sea region of Turkey and analysed for Fe and Mn content using XRF. Such work appears not to have been reported so far.     

常见花茶的功能成分与生物活性研究进展

花茶是通过对植物的花或者叶子进行一种更深层次的加工而形成的茶,因其富含多种营养功能成分,对人体的健康有积极地作用。花茶不仅具备养生的功能,同时还有一定的健身功效,因此人们在日常的生活、学习、工作过程中,都喜欢将其作为日常的饮品。近年来,随着经济的快速发展,花茶市场越来越兴盛,花茶种类繁多,有玫瑰花茶、有茉莉花茶、金银花茶、菊花茶、桂花茶和蒲公英等各类花茶百余种。该研究综述了茉莉花茶、玫瑰茶、菊花茶、金银花茶四种常见花茶的营养成分、活性成分及生物活性研究进展。总结发现,上述四种花茶富含蛋白质、维生素、多糖、儿茶素、茶碱类、黄酮类、挥发油类等营养和功能成分,具有抗氧化与延缓衰老、提高免疫力、防治心血管疾病、杀菌抑菌等生物活性。     

牛奶对茶汤纳米聚集体茶多酚分布特性的影响

茶汤纳米聚集体是茶多酚和蛋白质等自组装而成的纳米胶粒,是各组分介于游离分子与沉淀颗粒的中间状态。为探究牛奶对茶汤茶多酚分布特性的影响,本研究以云南大叶种蒸青绿茶、红茶为原料,以1:50茶水比浸提茶汤,按不同比例添加全脂、半脱脂和脱脂牛奶,利用超滤离心技术分离茶汤纳米聚集体,采用动态光散射技术分析各组茶汤纳米聚集体的总光强和平均直径,采用福林酚法分析其茶多酚浓度和分布率,比较研究牛奶添加比例、脂肪含量和茶类等因素对纳米聚集体物理化学特性和茶多酚分布特性的影响。结果表明:添加不同脂肪含量的牛奶均会促使部分牛奶纳米胶粒与茶汤纳米聚集体结合,导致茶汤超过90%的茶多酚富集于纳米聚集体,使绿茶和红茶的游离茶多酚比例分别降低78%和67%。初步证实:添加牛奶会促进绿茶、红茶的茶多酚参与分子聚集,使游离茶多酚比例大幅降低。     

茶叶产品开发现状与进展

茶叶具有独特的营养与保健功能，茶叶深加工是提高茶叶利用率、优化经济和社会效益的重要途径。本文综述了茶饮料、茶保健食品等茶叶产品的现状，并对新型产品的开发作了展望。     

茶树花中茶多酚和茶皂素综合提取技术研究

为了实现对茶树的综合利用,以茶树的花为实验材料,在单因素实验的基础上,采用正交实验方法对茶树花中茶多酚和茶皂素的综合提取工艺进行优化。分析了浸提时间、料液比、浸提温度、乙醇浓度和超声波功率对浸出率的影响。结果表明,乙醇浓度70%,超声波功率350W,浸提温度60℃,浸提时间10min,料液比1∶30g/mL时,茶多酚和茶皂素的综合得率最高,分别达到了28.38%和23.69%。     

黑茶微生物研究: 从群落组成到安全分析

形成黑茶主要品质特征的渥堆(或发花)工艺中的微生物来源于自然环境,不同地区黑茶的微生物多样性存在较大差异,为探讨黑茶微生物群落特征,本文综述了近年来国内外黑茶微生物方面的研究结果、黑茶微生物群落组成及安全分析。结果表明,曲霉属(Aspergillus)、青霉属(Penicillium)和散囊菌属(Eurotium)是黑茶微生物群落主要的组成部分,曲霉属真菌存在于黑茶加工的各个环节,青霉属真菌在初制渥堆过程中极少检出,但普遍存在于贮存环节。采用宏基因组技术对普洱茶渥堆样进行研究发现,细菌是其微生物群落的主要部分,细菌与普洱茶品质特别是其功能成分的关系需要进一步研究。黑茶产品食源性细菌毒素风险极低,虽然存在大量真菌,但黑茶在安全仓储下极少检出真菌毒素,正规厂家生产的黑茶产品是相对安全的。     

Metabolomics in quality formation and characterisation of tea products: a review

Tea is one of the biggest categories of modern non-alcoholic beverages with health benefits. Through different processes, tea products are divided into six main types: green tea, yellow tea, white tea, oolong tea, black tea and dark tea. Metabolomics is helpful for the comprehensive, accurate and rapid determination of tea metabolites in different types of tea products and tea processing materials. It has been widely applied in studying the relationship of tea metabolites and its quality. Therefore, it is necessary to summarise the application of metabolomics in tea. In this review, we described and summarised (1) the main metabolites of six types of tea and their implications on tea quality with emphasis on the content differences in the main metabolites in different types of tea; (2) the research on optimising the key processing steps of six types of tea based on metabolomics and the discussion of various new strategies for effectively improving their quality and (3) the advanced approach to characterise and distinguish different grades of tea products via metabolomics. The current review offers guidance for the improvement of tea quality by metabolomics and its potential challenges.     

亚太地区茶及类茶植物饮料(草药茶)发展现状及趋势

茶及类茶饮料是近20年来在亚、太地区流行的一种低糖型饮料。由于其醇和甘爽的口感及极富特色的鲜量色调，深度青少年及女性青睐。而其抗氧化、降血脂、消炎灭菌及预防糖尿病等多种保健功能也使中、老年饮者逐渐接受。在分析茶饮市场、预测其流行趋势同时，向读者推荐一批具有巨大市场潜力茶饮之原料，供商家参考。     

茶叶挤压膨化加工与综合利用研究进展

挤压膨化加工作为现代食品加工高新技术之一,已被广泛应用于食品及饲料等多个领域中。利用挤压膨化加工可使食品物料中的淀粉糊化和蛋白质变性,以及有效改善饲料的适口性,提高其生物利用率。目前,中低档茶叶如夏秋茶等因其存在苦涩味重且价格较低等问题,导致其开发利用程度相对较低。若利用挤压膨化技术将中低档茶叶进行挤压膨化加工,能有效降低其苦涩味,增加其生物利用度。此外,膨化后的茶叶再经粉碎后还能作为食品或饲料的添加原料而制成含茶食品或茶饲料,进而提高中低档茶叶的综合利用途径。本文介绍食品挤压膨化加工特性及其在茶叶领域的开发与应用前景,以期为更合理、更科学地利用膨化加工开发含茶食品或茶饲料相关研究提供参考。     

红茶汁液态发酵生成的泡沫组成分析与调控

为明确红茶汁液态发酵过程中生成的泡沫组成,对通气发酵过程的泡沫进行分离,采用分光光度计和高效液相色谱仪分析茶多酚、氨基酸和茶皂素、儿茶素、茶黄素等非挥发性化合物,并采用顶空固相微萃取结合气相色谱-质谱联用技术分析挥发性化合物的含量分布。结果表明：红茶汁匀浆和通气过程产生的泡沫中茶皂素、茶多酚、咖啡碱、部分儿茶素和茶黄素的质量浓度较隔离泡沫的茶汁中高,挥发物总量和癸醛、柠檬醛、芳樟醇、香叶醇和β-紫罗兰酮5 种呈甜花香化合物,己醛、1-辛烯-3-醇、苯乙醛、水杨酸甲酯和(E)-2-己烯醛5 种呈青气化合物也有提高,这表明产生的泡沫会带走较多的品质成分。为保留品质成分,向红茶汁发酵液中添加消泡剂防止泡沫形成,发现体积分数0.2%的消泡剂可有效控制泡沫形成,对茶多酚、氨基酸的质量浓度无显著影响,对发酵进程无不利影响,而且可促进茶汁中挥发物的释放。     

茶与茶渣的高值化综合利用

中国既是茶的原产地,也是茶的生产与消费大国,每年由于茶饮料及茶叶深加工产生大量的茶渣,仅仅以简单地丢弃处理而没有被高值化综合利用,既给环境带来了巨大的压力也造成了资源的浪费。茶渣中含有10%至16%粗纤维以及少量的络合态色素、矿物质、氨基酸、茶多酚、咖啡碱等,可以被多种形式地精深加工利用。本文综述了茶渣作为主要配料在作菌类的培养基、动物饲料的添加剂、植物的土壤肥料等方面的应用,以期为茶与茶渣的研究与利用提供参考。     

茶叶生物活性成分的功能与提取制备

为了充分利用低档茶叶中的生物活性成分,介绍了茶叶中所含茶多酚、茶多糖、茶蛋白、氨基酸、咖啡碱及维生素等具有抗氧化、抗肿瘤等生物活性成分,以及通过溶剂浸提和柱层析分离纯化等提取制备茶叶生物活性成分的方法,认为将这些活性成分应用于食品、化工及医药等行业,具有广阔的前景。     

十九世纪中叶英国人论茶

中国茶于17世纪传入欧洲，根据相关历史资料考证，首先开展中国和西方茶叶贸易的是荷兰人。但是最早用近代科学方法对中国茶及类似茶类饮料进行研究的却是英国人，出版于1850年的The Chemistry of Comnlon Life一书便总结了如茶、咖啡、可可和其它植物性饮料早期的科学研究成果。这本书在1880年被译成中文，书名《化学卫生论》。本文便是在解读该书有关茶等植物饮料知识的基础上，进一步和当代的研究成果进行比较。     

茶叶中污染微生物分析及茶多酚抑菌性研究

对茶饮料中茶叶原料的微生物种类进行了分析、鉴定,并对茶多酚对茶叶中污染微生物的抑菌性进行了研究。结果表明,茶叶中主要污染微生物是枯草芽孢杆菌、阴沟肠杆菌和黑曲霉。当茶饮料中茶多酚含量大于0.6g/L时对枯草芽孢杆菌有很好的抑制作用,而茶多酚含量小于1.2g/L时对阴沟肠杆菌、黑曲霉无抑制作用。实验表明正常的杀菌条件可将阴沟肠杆菌和黑曲霉杀死。因此为保障产品安全,建议茶饮料的茶多酚含量大于0.6g/L。     

Determination of essential and non-essential elements in various tea leaves and tea infusions consumed in Turkey

Tea is one of the most popular beverages in the world. Thus, the chemical components in tea are of great interest, especially in relation to health. In this study, 12 tea samples (10 black, 1 white and 1 green) and 5 herbal tea samples were purchased from supermarkets in Izmir, Turkey. Sample preparation has been performed using wet and microwave digestion procedures. The elemental content (Fe, Zn, Cu, Mn, Ni, Na and K) in the digests and infusions has been analysed. Generally, elemental contents in tea leaves were found to be higher than those in tea infusions. The accuracy of the method was checked and confirmed by standard reference material analyses. The comparison of wet and microwave digestion has not shown significantly different results. Therefore, the microwave digestion procedure was preferred because it is less laborious. The elemental intake related to tea consumption has also been studied.     

香茗入馔亦佳馐——古今茶膳饮食文化研究

在历史悠久的中华茶文化中，茶不仅是健康理想的饮料，而且可以用茶入馔，配合其他食品原料制作成为菜肴、面点、粥品、汤羹之类，统称之谓茶膳。茶膳也由此成为中国饮食文化、烹饪文化的组成部分之一。中国不仅是茶的原产地。是茶的故乡，而且也是茶膳最为发达的地方，丰富多彩的茶菜肴茶面点，以及各种充满茶之芬芳的粥品汤羹与小吃等，既丰富了国人的餐桌，也展示了中华民族精湛的烹饪技艺。更由于茶有很多益于人体健康的因子与功效，诸如健胃消食、提神醒脑、降脂清毒等等，所以进入二十一世纪以来，人们出于对健康的需求，茶膳在近几年来又成为炙手可热的保健食品，在餐饮市场上大行其道，而且大有方兴未艾的势头。     

茶鲜叶和茶花水提液对胆酸盐的结合及其降血脂机理的研究

在体外模拟人体消化环境,研究分析杀青、不杀青茶鲜叶和茶花水提液在体外对各种胆酸盐的结合能力,同时探讨杀青、不杀青茶鲜叶和茶花中的主要功能性成分茶多酚与胆酸盐结合的相关关系。结果表明:杀青茶鲜叶的水提液结合胆酸盐的能力最强,其次是茶花水提液、不杀青茶鲜叶的水提液。结合各种胆酸盐能力与各种水提液的茶多酚含量呈显著性相关关系,结果初步证明茶叶、茶花的功能性成分对人体具有降血脂功能。     

A Review on Kombucha Tea—Microbiology,Composition, Fermentation,Beneficial Effects,Toxicity, and Tea Fungus

Fermentation of sugared tea with a symbiotic culture of acetic acid bacteria and yeast (tea fungus) yields kombucha tea which is consumed worldwide for its refreshing and beneficial properties on human health. Important progress has been made in the past decade concerning research findings on kombucha tea and reports claiming that drinking kombucha can prevent various types of cancer and cardiovascular diseases, promote liver functions, and stimulate the immune system. Considering the widespread reports on kombucha, we recognized the need to review and update the research conducted in relation to kombucha tea, its products and tea fungus. Existing reports have suggested that the protective effects of kombucha tea are as good as those of black tea, however, more studies on kombucha tea and its composition are needed before final conclusions can be made.     

绿茶、红茶和乌龙茶抗氧化性能的比较

采用流动注射化学发光法研究了绿茶、红茶和乌龙茶的抗氧化性能。实验结果表明:绿茶、红茶和乌龙茶能有效的抑制超氧阴离子自由基诱导的鲁米诺化学发光,并且随着发光体系中绿茶、红茶和乌龙茶浓度的升高,发光强度呈现下降趋势即具有较强的抗氧化性能,对绿茶、红茶和乌龙茶的抗氧化性能进行了比较。