微机控制乌龙茶做青环境系统的研究

微机控制乌龙茶做青环境系统温度控制范围为20—28℃±1℃,湿度控制范围为相对湿度55—75％±3—5％,能有效地控制乌龙茶做青环境,保证茶叶品质稳定,四季均可制高档茶。做青时间缩短50％,大大减轻了人工劳动强度。乌龙茶品质可比传统人工方法做青提高1～2级,每公斤干毛茶可增值2—3元,提高了乌龙茶出口创汇能力。该系统还可应用于其他农副产品加工与贮藏保鲜所需的环境控制上。     

黄旦茶树品种适制性分析

以广西南亚热带农业科学研究所无公害茶园的黄旦茶树品种的鲜叶为原料,按照毛尖绿茶的加工工艺加工绿茶、乌龙茶的加工工艺加工乌龙茶、功夫红茶的加工工艺加工红茶,加工出的绿茶、乌龙茶、红茶均采用感官审评的方法来评价黄旦茶树品种的适制性。结果表明:黄旦茶树品种适合制作红茶和乌龙茶产品,不适合加工绿茶产品。     

闽北乌龙茶机械采摘鲜叶做青技术

做青技术是决定闽北乌龙茶品质的关键工艺,做青过程必须遵循"看青做青"的技术原则。基于此,以金观音为例,对机械采摘的不同成熟度鲜叶采用不同的闽北乌龙茶做青技术,以探索总结机械采摘不同成熟度鲜叶的做青技术。旨在为闽北乌龙茶生产提供实践经验。     

茶树新品种金牡丹引种试种初报

在龙州茶区引进茶树新品种金牡丹进行试种.结果表明,在龙州茶区,金牡丹在冬季有保护性栽培措施的条件下,生长良好,产量较高,适制绿茶和乌龙茶.其所制的乌龙茶花香馥郁,滋味醇厚芬芳,具有较高的经济价值.     

粤北高山乌龙茶生产技术分析

广东省高山乌龙茶区生态环境好,生产出的茶鲜叶品质优,无污染,市场销售佳,前景好。提高茶叶初制技术和优质率是提高效益的关键,针对粤北高山乌龙茶的生产技术进行研究阐述,以供参考。     

闽南乌龙茶烘焙技术初探

烘焙干燥是乌龙茶加工过程中的重要工序。烘焙对于茶叶品质的影响表明,温度是影响茶叶干燥效果的主因,说明乌龙茶干燥是在一定温度下完成的,始终存在热化作用。基于此,主要探讨了茶叶烘焙的几种形式及其优缺点,总结了个人见解:就实用而言,电焙优于炭焙;就风格特色而言,炭焙优于电焙。     

中低档乌龙茶中茶多糖提取工艺优化

该文以中、低档乌龙茶为原料，通过正交试验，研究了浸提温度、浸提时间、料水比和乙醇浓度4个因素对茶多糖得率的影响，并探讨茶多糖中蛋白质的脱除技术。研究结果表明：浸提温度对茶多糖得率的影响程度达到极显著水平，浸提时间、料水比和沉淀的乙醇浓度对茶多糖得率没有显著影响。乌龙茶茶多糖提取的最佳工艺条件为：浸提温度90℃，浸提时间80 min，料水比1∶25，沉淀剂乙醇浓度60％，乌龙茶茶多糖得率为10.15%，含量88.04%。以3次脱蛋白处理为宜，茶多糖中蛋白质脱除率为64.22％。另外，经红外光谱和紫外光谱分析，乌龙茶茶多糖主要是吡喃多糖，并且有蛋白质特征吸收峰。     

清香型乌龙茶品质形成中游离氨基酸指纹图谱变化规律

为探明游离氨基酸在茶树新梢生育过程的代谢变化及清香型乌龙茶制作工艺对其指纹图谱化学模式的影响,分别以铁观音、黄棪、金观音和黄观音品种春茶新梢为供试材料,对其新梢生育及乌龙茶制作过程中的游离氨基酸进行高效液相色谱-AQC(6-氨基喹啉基-N-羟基琥珀酰亚氨基甲酸酯)柱前衍生化检测分析。结果表明,18种已标定游离氨基酸指纹峰面积经标准化(尤其是自然对数变换)数据预处理后,再进行相似度分析(夹角余弦)、聚类分析法(欧氏距离-近邻法)和主成分分析,均可获得较为一致的可视化模式识别结果。4个茶树品种可划分为铁观音和黄棪、金观音和黄观音2个类群,不同生育期芽叶与清香型乌龙茶在制品可进行较好区分。茶氨酸、甘氨酸、谷氨酸等8种主要游离氨基酸在茶树新梢生育过程中发生较为明显的增减变化,且在中、小开面2～4叶中的含量相对较低;在清香型乌龙茶制作过程中,各主要游离氨基酸含量发生小幅变化,毛茶成品中略有增加。由此可见,游离氨基酸在茶树新梢生育过程中含量及组成的动态变化较清香型乌龙茶制作工艺的影响更为明显。该研究结果可为清香型乌龙茶鲜叶原料选取和品质工艺控制提供参考。     

不同工艺制法对茶叶风味品质化学轮廓的影响

为探明不同工艺制法对茶叶风味品质化学轮廓的影响,本研究对福建4种茶类(绿茶、白茶、红茶和乌龙茶)及其鲜叶原料中的主要滋味和香气品质成分进行了检测分析和可视化模式识别。结果表明,基于茶叶主要滋味品质成分的主成分分析(PCA)可将全部供试茶样划分成3种类群:Ⅰ型:绿茶、白茶和一芽二、三叶鲜叶样;Ⅱ型:乌龙茶和中、小开面2~4叶鲜叶样;Ⅲ型:红茶。采用偏最小二乘增强判别分析(PLS-EDA)可进一步放大不同类群茶样的组间差异,乌龙茶及其鲜叶原料有较高含量的水溶性碳水化合物(WSCs),而红茶中多酚类(TPs)和表没食子基儿茶素没食子酸酯(EGCG)含量相对较低;(茶多酚×游离氨基酸)含量二维散点视图可作为茶叶分类识别的一种重要判别工具。4种茶类以乌龙茶的香型种类最为丰富,绿茶与鲜叶原料的香气组成化学模式较为接近,白茶与红茶香气组成在种类和数量上存在一定的相似特征。2,6-二叔丁基对甲苯酚、苯乙腈、4-乙基苯甲酸-2-苯基乙酯类似物、反式-橙花叔醇、α-法呢烯、吲哚等可视为乌龙茶有别于其他3种茶类(绿茶、白茶和红茶)的主要特征香气成分。本研究结果为茶叶化学分类及其工艺品质的目标控制提供了参考依据。     

乌龙茶在浸提中温度和时间的最佳决策研究

从研究乌龙茶在浸提中的温度和时间对茶汤内质的影响,提出在工业生产茶汁,速溶茶的浸提过程的最佳温度和时间。     

基于高光谱成像的茶叶中EGCG分布可视化

针对目前关于表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)在茶叶中的分布缺乏可视化表达问题,该文采用高光谱成像技术以实现EGCG在茶叶中的分布可视化。通过高光谱成像仪采集茶叶的光谱信息,按照标准方法 HPLC(high performance liquid chromatography)法测量茶叶的EGCG浓度。运用化学计量学方法建立光谱与EGCG浓度之间的回归模型。为寻求相对较优的模型效果,对光谱进行不同的预处理,以确定最优的预处理方法;采用4种建模方法建立回归模型,以确定最优的建模方法;对光谱进行特征波段选择,以降低数据冗余提高模型的稳定性和运算速度。最后,将高光谱图像中像素点对应的光谱变量导入模型,从而生成EGCG浓度分布图。结果表明:可见-近红外光谱与EGCG浓度之间具有很强的相关性,其回归模型的决定系数达到0.905,利用高光谱成像技术对茶叶中EGCG分布进行可视化可行。通过对不同品种、叶位的茶叶中EGCG浓度分布进行可视化,能够为高EGCG浓度茶树品种的培育、EGCG代谢规律的分析以及茶树采摘部位的识别提供有效手段。     

便携式茶鲜叶品质光谱检测装置研制

品质监测对茶鲜叶适时采摘和茶叶加工品控具有重要意义。该研究基于可见/近红外光谱技术，研发了便携式茶鲜叶品质无损检测装置。该装置分为主机和手柄2部分，主机大小约240 mm×250 mm×240 mm，包括光谱仪、光源、可充电锂电池、稳压板和散热风扇；手柄大小约130 mm×100 mm×30 mm，包括光纤探头、金属灯杯、白参考板和外触发按钮。基于该设备，采集了茶鲜叶500～900 nm范围内可见/近红外漫反射光谱，对比了归一化（Normalize，NOR）、一阶导数（First Derivative，FD）、标准正态变量变换（Standard Normal Variable Transformation，SNV）和概率商归一化（Probabilistic Quotient Normalization，PQNOR）等不同光谱预处理方法对茶叶光谱的处理结果，建立了茶鲜叶干物质含量、水浸出物含量、茶多酚含量的偏最小二乘定量预测模型。结果表明，PQNOR预处理后建立的偏最小二乘预测模型精度最好，干物质、水浸出物和茶多酚含量预测模型在验证集的相关系数分别为0.905、0.896和0.747，均方根误差分别为0.856%、0.559%和0.549%。在茶园对装置的精度进行了现场测试，单片茶鲜叶检测时间约为1 s，干物质、水浸出物和茶多酚含量预测值与测量值的均方根误差分别为0.903%、0.634%和0.551%。该装置可以实现茶鲜叶光谱原位采集和干物质含量、水浸出物、茶多酚的定量分析，对及时掌握茶树生长情况、辅助决策采茶方案和保障茶叶品质具有重要作用。     

茶多酚对生鲜面品质及抗氧化特性的影响

为探究茶多酚对生鲜面品质及抗氧化性的影响,利用质构仪、扫描电子显微镜、感官评价和抗氧化模型,分别研究添加0、0.1%、0.5%、1.0%茶多酚的生鲜面的蒸煮特性、质构特征、微观结构、感官品质、贮藏品质以及自由基清除率。结果表明,添加茶多酚后,面条的硬度和咀嚼性均显著增强,面条整体的面筋网状结构变得致密、均匀,内部结构得到明显改善;此外,茶多酚的添加可以有效抑制微生物的生长。在本试验条件下,茶多酚添加量为0.5%时,感官评价总分最高,且DPPH和ABTS自由基清除率较对照均提高了1.5倍,表明在面条中添加0.5%茶多酚可生产出具有一定生理功能的生鲜面产品。本研究结果为功能性生鲜面产品的加工提供了理论依据。     

绿茶生产质量信息管理系统设计与实现

为提高茶叶生产的质量安全监控信息化水平及茶叶生产企业管理的信息化水平,减少因茶园施肥、用药、加工等所造成的茶叶质量安全问题,将信息技术和茶叶生产质量管理关键控制点结合起来,采用计算机技术、网络数据库技术,设计并开发了绿茶生产质量信息管理系统,实现了绿茶产地环境、种植环节、加工过程及包装储运等质量关键控制点信息的网络化管理。     

辐照降解绿茶甲氰菊酯和溴氰菊酯的可行性研究

对^60Coγ射线辐照降解茶叶中甲氰菊酯和溴氰菊酯的可行性进行了探讨。经5kGy辐照后,分别喷施过2种农药的茶鲜叶中,甲氰菊酯的降解率为7.3%,溴氰菊酯为14.7%;加工为成茶后的绿茶中甲氰菊酯的降解率为2.2%,溴氰菊酯为12.1%。甲氰菊酯在茶鲜叶中的辐照降解率比在绿茶中高5.1%,溴氰菊酯在茶鲜叶中的辐照降解率...     

Factors affecting the levels of tea polyphenols and caffeine in tea leaves

An isocratic HPLC procedure was developed for the simultaneous determination of caffeine and six catechins in tea samples. When 31 commercial teas extracted by boiling water or 75% ethanol were analyzed by HPLC, the levels of (-)-epigallocatechin 3-gallate (EGCG), and total catechins in teas were in the order green tea (old leaves) > green tea (young leaves) and oolong tea > black tea and pu-erh tea. Tea samples extracted by 75% ethanol could yield higher levels of EGCG and total catechins. The contents of caffeine and catechins also have been measured in fresh tea leaves from the Tea Experiment Station in Wen-Shan or Taitung; the old tea leaves contain less caffeine but more EGCG and total catechins than young ones. To compare caffeine and catechins in the same tea but manufactured by different fermentation processes, the level of caffeine in different manufactured teas was in the order black tea > oolong tea > green tea > fresh tea leaf, but the levels of EGCG and total catechins were in the order green tea > oolong tea > fresh tea leaf > black tea. In addition, six commercial tea extracts were used to test the biological functions including hydroxyl radical scavenging, nitric oxide suppressing, and apoptotic effects. The pu-erh tea extracts protected the plasmid DNA from damage by the Fenton reaction as well as the control at a concentration of 100 microg/mL. The nitric oxide suppressing effect of tea extracts was in the order pu-erh tea >/= black tea > green tea > oolong tea. The induction of apoptosis by tea extract has been demonstrated by DNA fragmentation ladder and flow cytometry. It appeared that the ability of tea extracts to induce HL-60 cells apoptosis was in the order green tea > oolong > black tea > pu-erh tea. All tea extracts extracted by 75% ethanol have stronger biological functions than those extracted by boiling water.     

Identification and comparison of phenolic compounds in the preparation of oolong tea manufactured by semifermentation and drying processes

Oolong tea manufactured via a semifermentation process possesses a taste and color somewhere between green and black teas. Alteration of constituents, particularly phenolic compounds, in the infusion of oolong tea resulting from its manufacture, was analyzed by high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry. The identified constituents contained 2 alkaloids, 11 flavan-3-ols, 8 organic acids and esters, 11 proanthocyanidin dimers, 3 theaflavins, and 22 flavonoid glycosides, including 6 novel acylated flavonol glycosides. The tentative structures of these 6 novel compounds were depicted according to their mass fragmentation patterns in MS(n) (n = 1-4). In comparison with caffeine as an internal standard, relative contents of the constituents in the infusions of fresh tea shoot and different oolong tea preparations were examined. Approximately, 30% catechins and 20% proanthocyanidins were oxidized during the manufacture of oolong tea from fresh tea shoots, and 20% of total flavonoids were decomposed in a follow-up drying process. Gallocatechin-3-O-gallate and theaflavins putatively produced in the semifermentation process of oolong tea were not detected in fresh tea shoots, and the majority of theaflavins were presumably transformed into thearubigins after drying.     

Identification of processed Japanese green tea based on polymorphisms generated by STS-RFLP analysis

In Japan, tea is generally sold blended, though 90% of the total production is clonal. Due to the increasingly strict consumer need and taste, however, more and more Japanese green teas are being sold under their particular cultivar name. Moreover, tea made from Yabukita, a much appreciated cultivar originally developed in Japan, has recently been produced and imported from a neighboring country. This paper describes a simple and inexpensive methodology capable of identifying fresh and processed Japanese green teas to discourage its fraudulent commercialization. The study was based on 46 main tea cultivars, and polymorphism detected through STS-RFLP analysis of the coding and noncoding DNA regions of three genes, namely phenylalanine ammonia-lyase, chalcone synthase, and dihydroflavonol 4-reductase, for which nucleotide information was available. All 46 tea cultivars analyzed could be easily distinguished using a combination of codominant DNA markers. Yabukita displayed a unique profile when PAL intron was digested with DdeI, thus allowing its rapid authentication at low cost.     

论茶园灌溉工程和灌溉效益

从湖南情况出发,论述了在干旱明显的地区、在基础较好的茶园里建立灌溉工程的必要性。鉴于茶园大多居于山区丘陵地段,指出了固定式喷灌系统更能适应于茶叶大田生产。文中应用有关科研成果和大生产的经验提出了科学用水的理论依据,节能灌溉的指标,以及能适应大生产应用的技术参数。最后系统地阐述了由于灌溉改善了荼园的生态环境,从而提高了茶叶的产量和鲜叶的自然品质,它能获得良好的经济效益。结论是:兴建灌溉工程,作为一项新的工程技术和生物技术相结合的农艺措施,对发展茶叶生产具有一定的意义。