普洱茶茶渣中茶多糖的超声波辅助提取及其抗氧化性

为了解决普洱茶茶渣所带来的环保问题,本研究探讨了普洱茶茶渣中茶多糖超声波提取的优化工艺,并研究了最佳提取工艺条件下的茶多糖的抗氧化性。在单因素实验基础上进行响应面试验,制定了茶多糖超声波辅助提取工艺的4因素3水平响应面法试验设计方案。研究结果表明,普洱茶茶渣中茶多糖超声波提取的最佳试验因素组合为:浸提温度为100 ℃、浸提时间为120 min、料液比为1:30 g/mL,超声波功率为420 W。在此条件下,茶多糖得率为2.29%。该工艺所得茶多糖对羟基自由基以及超氧离子自由基均具有较强的清除能力:当茶多糖浓度为3.2 mg/mL时,茶多糖对羟基自由基的清除率达到最高,为60.37%;当茶多糖浓度为2.4 mg/mL时,茶多糖对羟基自由基的清除率达到最高,为53.91%。     

茶饲料的巧用与效果

速溶茶制取与茶叶沏泡 ,能利用占茶叶干重30 %～ 4 0 %的可溶性成分 ;这些成分主要是茶多酚、咖啡碱、糖类、水溶性灰分、氨基酸和维生素等。而在占茶叶干重 60 %～ 70 %的废茶渣中 ,含有 18%～2 0 %粗蛋白、11%～ 13%粗纤维、0 .5 %～ 1%粗脂肪、8%～ 9%矿物质 ,其余为易提取物和含氮物质 ,适宜用来制作茶饲料。但废茶渣中的含氮化合物必须先经发酵处理才能为家禽、家畜所利用 ,且发酵处理还能使有效氮增加两倍。茶饲料加工一般可采用如下的工艺流程 :茶叶废料→除表面水→烘干至含水率 6%～ 8%→机械粉碎→灭菌 (热处理 )→反应堆搅拌 (加…     

茶渣中蛋白质提取方法研究进展

中国是茶叶生产与消费大国,每年在生产茶多酚、茶饮料、速溶茶等产品的同时,产生大量的剩余残渣,这些茶渣中残留多种营养成分,其中蛋白质含量高达20%左右,绝大部分是非水溶性蛋白质的谷蛋白和醇溶性蛋白,同时研究发现茶蛋白具备降血脂、抗氧化、消除自由基及预防辐射等积极的作用;但茶蛋白结构复杂,对茶渣中茶蛋白的提取、纯化等均有一定的技术难度,本文主要针对茶蛋白提取方法(碱法提取、酶法提取、复合提取法)、茶蛋白纯化及茶蛋白的特性等进行阐述,并对存在的问题进行了讨论,以期为茶渣中蛋白质的研究提供参考。     

3种安徽名茶功能性成分浸出条件及茶渣资源化研究

目的探究不同浸泡条件对茶叶功能性成分浸出量和茶水自由基清除能力的影响及实现茶渣资源化。方法选取安徽3种特色茶叶(祁门红茶、黄山毛峰、六安瓜片)作为研究对象,采用紫外分光光度法分别测定在不同浸泡条件下(5、10、30、60、120 min、60、75、90、100°C、一浸液、二浸液、三浸液)茶叶中功能性成分茶多酚、茶氨酸、茶多糖的浸出情况以及茶水对自由基的清除效果,并考察了浸泡后的茶渣对甲醛和重金属铬(Cr)的吸附效果,以及茶渣炭化后对吸附作用的影响。结果 3种茶叶的3种功能性成分浸出率都随时间和温度的增加而增大,随浸泡次数的增加而减小,而茶汤自由基清除能力受浸泡时间和浸泡温度的影响不大,但随浸泡次数增大而减小。黄山毛峰和六安瓜片的有效成分浸出率及自由基清除能力都大于祁门红茶;茶渣对甲醛和Cr均有一定的吸附作用,红茶渣对甲醛的吸附率较另外2种茶渣略低,但对于Cr,红茶渣吸附能力明显强于黄山毛峰和六安瓜片;炭化的茶渣对甲醛和Cr的最大吸附能力较炭化前增强了0%～50%,且茶渣的吸附平衡时间明显缩短,但茶叶种类对炭化后茶渣的吸附能力没有明显影响。结论温度、时间和浸泡次数均会影响茶叶功能性成分浸出量和茶水的自由基清除能力,可利用茶渣的吸附功能实现其资源化,而茶渣炭化可提高其作为吸附剂的使用价值。     

双偶氮染料的茶渣固态漆酶脱色

利用变色栓菌茶渣固态发酵制备的茶渣固态漆酶对双偶氮类染料进行脱色,并以直接耐晒黄RS为代表,研究其脱色机制和脱色效果。结果表明,在茶渣固态漆酶用量为160 U/L、染料质量浓度为100 mg/L条件下反应2 h后,直接耐晒黄RS的脱色率达到81.10%。研究发现,茶渣固态漆酶的脱色机制包括游离漆酶降解、茶渣吸附和固定化漆酶降解三部分,对直接耐晒黄RS的脱色率分别为16.40%、43.20%和19.70%。茶渣固态漆酶在染料脱色中表现出较好的重复使用性能,重复利用4次,脱色率仍保持在50%以上。毒性检测结果表明,绿豆种子的萌发率从36.67%提高到85%,脱色后染料溶液毒性明显下降。利用茶渣固态漆酶对染料脱色具有时间短、效率高、可重复利用和成本低等优势,在染料脱色方面具有良好的前景。     

茶叶综合利用之茶渣生物质颗粒燃料

近年来,随着茶叶深加工领域的不断拓展,茶饮料、速溶茶及茶多酚等产品的产量迅速增长,由此产生了大量茶渣,如何合理处理这些茶渣成为研究人员广泛关注的问题。茶渣制备成生物颗粒质燃料是一种新型的茶渣处理途径,具有环保、经济、可持续发展的特点。本文介绍了茶渣的来源、利用价值以及茶渣综合利用现状,重点介绍茶渣生物质颗粒燃料的生产及应用前景,为后续的茶渣综合利用研究提供理论依据。     

茶叶蛋白质的改性及其功能性质研究

将从制取茶多酚之后的茶渣中提取并初步纯化的茶粗蛋白进行酸法和酶法水解改性,可大大改善其功能性质指标如溶解性、吸水性、起泡性、乳化性和凝胶性,吸油性稍有降低。改性后的茶蛋白主要功能性质可与大豆分离蛋白媲美,水解程度对上述功能性质有不同程度地影响。在AP-TEMED体系中测定,当该茶粗蛋白浓度为0.1mg/L时对O_2~-·自由基的清除率为52.0%。     

茶渣蛋白的提取及酶解产物抗氧化性质研究

我国是茶叶生产消费大国,茶渣中含有丰富的蛋白质,茶渣蛋白具有良好的营养价值和保健功效。以茶渣为原料,以超声波技术为辅助手段,得到茶渣蛋白的最佳提取工艺:料液比为1:70(g/mL)、超声功率150 W、超声波提取时间为70 min、提取温度为90℃、NaOH浓度为0.18mol/L,该条件下茶渣蛋白提取率最大值为(83.17±0.16)%。利用碱提酸沉法得茶渣蛋白,以抗氧化能力为指标利用复合蛋白酶对茶渣蛋白进行酶解得到抗氧化肽,优化得最佳条件:底物浓度1.0%、酶/底物8000 U/g、酶解温度为60℃、pH为8,得茶渣蛋白酶解产物DPPH自由基清除率达到(80.83±0.47)%。在亚油酸体系中,1.0 mg/mL茶渣蛋白酶解产物对亚油酸体系自氧化的抑制能力高于抗坏血酸和VE,略低于人工合成抗氧化剂BHT。     

茶渣栽培平菇的子实体营养成分分析

检测和分析了以不同比例添加的速溶茶加工残渣为基质,并以棉籽壳基质作为对照所栽培的三个平菇菌种子实体的蛋白质、氨基酸和多糖等营养成分以及矿物质元素的含量。结果表明:利用茶渣作为培养基质,能够栽培出高蛋白质和高氨基酸含量的平菇,而且,随着茶渣添加比例的增加,其子实体的蛋白质、氨基酸以及矿物质含量也逐渐增加,但是其多糖含量却随着茶渣比例的增加而呈下降趋势。本研究为利用茶渣取代传统的棉籽壳基质培养高产高品质的平菇提供参考依据。     

茶渣的再利用研究进展

本文针对当前茶叶资源综合利用率较低、茶渣产量大及残留营养成分多的现状,重点对茶渣的再利用研究进展进行了综述,也对中药渣的再利用进行了引申。     

Cream formation in a semifermented tea

The formation of cream in Paochung tea, a popular semifermented tea, which undergoes a lesser degree of enzymic oxidation during manufacture, was investigated at various extraction temperatures, extraction times, pHs and leaf/water ratios. The primary components of Paochung tea cream were catechins (30%), caffeine (20%) and protein (16%). (−)-Epigallocatechin gallate and (−)-epicatechin gallate were the major catechins precipitated during creaming, constituting 19% and 5% of the tea cream respectively. The amount of tea cream produced and its composition were influenced by extraction temperature and pH. The tea leaf/water ratio determined the amount of tea cream formed but did not affect the cream composition. Catechins were considered to be the key component in tea cream. They interacted with caffeine and protein to induce tea cream formation. © 1999 Society of Chemical Industry     

Fate of imidacloprid and acetamiprid residues during black tea manufacture and transfer into tea infusion

The objective of this paper is to investigate the loss/stability of neonicotinoids (imidacloprid and acetamiprid) residues during the manufacture of black tea and to study the transfer of these pesticides from made tea to its infusion. For orthodox black tea, the manufacturing process involves leaf harvesting (plucking two leaves and a bud), withering, rolling, fermentation (oxidation), and drying. Initial withering and final drying resulted in the loss of pesticide residues, but no significant reduction in residue levels resulted from the rolling and fermentation steps. The drying process resulted in a residue transfer of 64–70% and 69–74% of the initial level, whereas the brewing process resulted in a residue transfer of 37–39% and 45–49% of imidacloprid and acetamiprid, respectively, from dried tea into the infusion. The decrease in acetamiprid levels during drying was also significant (8–13%), whereas the total loss during the manufacturing process ranged from 26 to 31%. Further, brewing for longer periods (an extended brewing time) resulted in higher transfer (up to 44% for imidacloprid and 53% for acetamiprid) of pesticides to tea infusion. Further, the extent of pesticide leaching depends on its water solubility, partition coefficient, and the brewing time.     

毒死蜱在茶叶上的残留消解动态与使用安全性

目的探讨毒死蜱在茶园的使用安全性。方法采用室内检测和田间试验方法,对45%毒死蜱乳油在茶叶上的残留消解动态进行研究。样品采用含体积分数1%乙酸的乙腈溶液超声提取,分散固相萃取净化,气相色谱电子捕获法测定。结果在0.005~2.0 mg/L范围内,毒死蜱的质量浓度与其峰面积呈良好的线性关系,相关系数大于0.9990;添加浓度为0.01、0.2和1 mg/kg时,毒死蜱在茶叶中的平均回收率为81.7%~110.7%,RSD小于10%,检出限、定量限分别为0.003 mg/kg、0.01 mg/kg。施药剂量为有效成分540~1080 g/hm2时,毒死蜱在茶叶上的残留量与施药剂量密切相关,施药后初期残留量迅速降低,而后平缓下降,消解动态符合一级动力学反应模型,半衰期为3.78 d~4.16 d,施药后21 d,残留量小于0.1 mg/kg。结论毒死蜱为适于在茶园使用的农药品种,参照欧盟茶叶上毒死蜱的最大残留限量标准(MRL),45%毒死蜱乳油按常规方法喷雾,制剂有效成分用量不超过1080 g/hm2,施药1次,安全间隔期大于21 d,在茶叶上的残留是安全的。但由于毒死蜱在茶树上尚未登记,因此不建议在茶园中使用。     

晒青茶、普洱茶(生茶)紧压茶实物样研制及其品质特征分析

根据普洱茶(生茶)拼配规则及各普洱茶生产企业的产品质量生产情况,为进一步推动普洱茶(生茶)实物标准样的科学制备,规范普洱茶原料及普洱茶(生茶)产品,揭示影响云南大叶种晒青茶滋味品质的物质基础,并探讨影响因素间的相互作用。以临沧、普洱、大理、西双版纳的春、夏、秋三个季节的云南大叶种晒青茶为原料：(1)通过筛选可拼配单样、小样试拼及排序、大样拼堆及评定等程序,严格通过品质水平均匀性、稳定性检验,制备出二套实物标准样：晒青茶实物标准样、普洱茶(生茶)实物标准样。(2)通过理化分析及感官审评,通径分析表明,茶多酚与氨基酸、黄酮是影响晒青茶滋味品质的主要因素,其中,黄酮对晒青茶的滋味品质直接作用最明显,茶多酚通过其余变量对晒青茶滋味品质的间接作用综合影响最大。本研究不仅为普洱茶的质量标准信息化研究、茶饮料开发等方面提供分析方法参考,更为促进普洱茶的高质量、绿色化、品牌化发展提供科学依据。     

Residue pattern of polycyclic aromatic hydrocarbons during green tea manufacturing and their transfer rates during tea brewing

ABSTRACT

Residues of polycyclic aromatic hydrocarbons (PAHs) in green tea and tea infusion were determined using gas chromatography-tandem mass spectrometry to study their dissipation pattern during green tea processing and infusion. Concentration and evaporation of PAHs during tea processing were the key factors affecting PAH residue content in product intermediates and in green tea. PAH residues in tea leaves increased by 2.4–3.1 times during the manufacture of green tea using the electric heating model. After correction to dry weight, PAH residue concentrations decreased by 33.5–48.4% during green tea processing because of PAH evaporation. Moreover, spreading and drying reduced PAH concentrations. The transfer rates of PAH residues from green tea to infusion varied from 4.6% to 7.2%, and PAH leaching was higher in the first infusion than in the second infusion. These results are useful for assessing exposure to PAHs from green tea and in formulating controls for the maximum residue level of PAHs in green tea.     

柿叶茶保健酒的开发

对柿叶茶保健酒的生产工艺进行了研究,结果表明,浓茶汁与柿叶茶浸泡酒液以1:1的比例混合制得柿叶茶基酒。柿叶茶保健酒的最佳配方为柿叶茶基酒80%、糖浆20%、柠檬酸0.15%及适量的调味酒。该产品不仅营养价值高,风味独特,而且还具有一定的保健作用。     

Persistence of acetamiprid in tea and its transfer from made tea to infusion

Acetamiprid, a new-generation, highly active neonicotinoid insecticide has been used to control mites and insect pests. In the present study, the disappearance trend of acetamiprid residue in tea under field conditions was studied at two dosages for two seasons (dry and wet), and transfer of residues from made tea to infusion was also determined. Acetamiprid dissipation rate was found to be faster in the wet season. Half-life of acetamprid was found to be 1.82–2.33 days in green tea shoots and 1.84–2.25 days in made tea for both dry and wet seasons. The percent transfer of acetamiprid residues from made tea to infusion was 36.84–50.00%; however, 31.11–44.40% of the residues remained stuck to the spent leaves during both the dry and wet seasons. On the basis of transfer of residues from made tea to infusion, a waiting period of 15 days for tea plucking after pesticide application at recommended dose may be suggested.     

Investigation of the presence and significance of theanine in the tea plant

Theanine was determined in black teas and tea plants by a combination method of thin-layer chromatography (t.l.c.) and densitometry. It was shown that in 20 samples of black tea from different qualities and sources the amount varied from 0.33 to 1.59 g 100 g^?1 dry wt. The highest quality black teas possessed the lowest amount of theanine, but it is subject to chemical degradation during black tea manufacture. The investigation of physiological function of theanine in the tea plant showed that during germination the theanine level reached a maximum after 45 days. This indicates that at this period of the growth of the tea plant theanine acted as a source of nitrogen and as a starting point for the synthesis of the carbon skeletal compounds of the tea plant. Theanine was found to exist in all parts of the tea plant but it accumulated more in young and active tissues and also in younger plants, which emphasises its metabolic role in the tea plant. The distribution of theanine in the shoots indicated that the first leaf was the principal site for the synthesis of polyphenolic compounds from theanine.     

不同干燥成形方式的白叶红茶品质分析

目的 研究不同干燥成形方式对白叶红茶品质的影响。方法 以白叶1号鲜叶为原料, 采用相同的萎凋、揉捻、初烘程序, 用不同的干燥做形方式制成不同形态的红茶,以感官审评结合理化分析的方法对不同形态的红茶进行了品质分析。结果 通过不同干燥成形方式获得了卷曲形、毛峰型、针形、扁形4种形态的红茶。4种红茶茶黄素、茶红素及氨基酸含量稍有差别,针形红茶茶黄素、类黄酮与氨基酸总量略高, 有利于提高其饮用价值,但4种红茶色、香、味感官品质总体接近。二次干燥(足火)-成形过程促使不同形态白叶红茶香气组成发生一定变化, 进而对红茶香型产生了细微影响,4种红茶以甜香为基本香型,卷曲型红茶香气特征偏于花香,扁形红茶略带果香。结论 毛火过程对白叶红茶品质的形成和固定具有关键意义, 干燥成形方式不改变总的香气特征, 但可使白叶红茶的具体香型发生细微分化。     

茶叶中生物碱检测方法的研究进展

茶叶作为主要饮品之一, 对茶叶品质评定是必不可少的一个过程。茶叶的品质除了感官评定其色、香、味, 还可通过测定其茶多酚、氨基酸、矿物质、蛋白质、生物碱等活性成分的综合含量来评定。生物碱是茶叶中的主要活性成分之一, 不仅决定着茶叶的品质, 对人体也具有一定的有益作用。生物碱的快速、高效检测方法是茶叶品质评估和茶叶中生物碱提取及含量检测的前提和关键。本文参考了国内及国外对茶叶中生物碱研究方法的相关文献, 对茶叶生物碱(主要是咖啡碱、可可碱、茶叶碱)最主要的检测方法进行了综述。为进一步研究茶叶中生物碱及测定其含量, 评估茶叶的品质提供参考。