英红九号六大茶类生化成分分析及体外活性评价

对英红九号茶树品种六大茶类(绿茶、白茶、黄茶、乌龙茶、红茶和黑茶)的生化成分含量进行分析,并进行体外活性评价。结果表明:英红九号六大茶类中生化成分特点是绿茶的可溶性糖和水浸出含量最高,白茶的各生化成分含量均处于其他茶类之间,黄茶的茶多酚和儿茶素含量最高,乌龙茶的氨基酸含量最高,黄酮和可溶性糖含量最低,红茶的黄酮含量最高,茶多酚、儿茶素、氨基酸和水浸出物的含量最低,黑茶的氨基酸和水浸出物含量较高,茶多酚和儿茶素含量较低,仅稍高于红茶。英红九号六大茶类的体外抗氧化活性表现为绿茶、乌龙茶和黄茶的活性较高,体外抑制α-淀粉酶活性表现为绿茶和乌龙茶的活性较高,体外抑制脂肪酶活性表现为黑茶活性最高,其他茶类活性相差不大。     

不同季节翠玉品种3大茶类生化成分及 抗氧化活性研究

对不同季节(春、夏、秋)翠玉品种3大茶类(绿茶、乌龙茶和红茶)的生化成分含量及抗氧化能力进行分析研究。结果表明:不同季节翠玉绿茶中,夏茶的抗氧化能力最强,其茶多酚、儿茶素总量较春茶低,但酯型儿茶素的含量为最高;不同季节翠玉乌龙茶中,夏茶的抗氧化能力最强,其茶多酚、儿茶素和酯型儿茶素的含量均为最高,其茶多糖的含量也较绿茶和红茶夏茶高;不同季节翠玉红茶的抗氧化能力差异不大。从不同茶类来看,翠玉品种的茶叶的抗氧化能力表现为绿茶乌龙茶红茶。     

红茶、绿茶、乌龙茶活性成分抗氧化性研究

目的与方法：通过醇提得到各种茶多酚提取液,酒石酸亚铁法测定了多酚的含量;水提得到各种茶多糖提取液,用硫酸- 苯酚法测定其中多糖的含量。通过DPPH·法、水杨酸法及邻苯三酚法测定不同茶叶中多酚、多糖含量对自由基的清除作用的影响,对比研究八种茶叶的抗氧化能力。结果：不同茶叶中多糖的含量从2.19%增大到2.89% (半发酵乌龙茶＞红茶＞绿茶),抗氧化能力：红茶＞绿茶＞乌龙茶(DPPH·法);红茶＞绿茶＞乌龙茶(水杨酸法);红茶＞乌龙茶＞绿茶(邻苯三酚法);不同茶叶中多酚的含量从1.71% 增大到9.75% (绿茶＞半发酵乌龙茶＞红茶);结论：茶多糖和多酚是茶叶的主要抗氧化成分。绿茶的抗氧化作用主要来自茶多酚,红茶的抗氧化作用主要来自茶多糖。除乌龙茶多糖提取液外,两种抗氧化成分的抗氧化能力与其含量成量效关系。     

4类紫娟茶化学成分与抗氧化活性比较

紫娟是富含花青素的特色茶树品种,其加工的绿茶和普洱生茶花青素含量也高于一般茶叶。目前市场上出现了紫娟红茶和普洱熟茶,经过发酵与后发酵,这些产品的花青素是否保留有待研究。文章测定并比较紫娟绿茶、红茶、普洱生茶与熟茶的茶多酚、儿茶素、花青素等化学成分以及抗氧化活性。结果表明,花青素、水浸出物、茶多酚和儿茶素等化学成分含量在紫娟绿茶和普洱生茶中较高,紫娟红茶和普洱熟茶中较低;4类紫娟茶都具有抗氧化活性,其中紫娟绿茶和普洱生茶提取物的总抗氧化能力(T-AOC法)和超氧阴离子、DPPH自由基、羟自由基清除能力较高,紫娟普洱熟茶和红茶提取物较低。相关性结果表明:除儿茶素与超氧阴离子相关性不显著外,其余儿茶素和牵牛花色素、飞燕草色素、矢车菊素等3种花青素单体均与4种抗氧化能力显著正相关(P0.05);茶多酚与羟自由基清除能力显著负相关(P0.05);水浸出物、芍药色素、天竺葵素、锦葵色素与DPPH自由基清除能力与总抗氧化能力显著正相关(P0.05)。此外,天竺葵素与羟自由基清除能力显著正相关(P0.05),锦葵色素与超氧阴离子清除能力显著正相关(P0.05)。感官审评表明,紫娟普洱生茶和绿茶滋味略苦涩,红茶和普洱熟茶滋味甜醇。综上,经过发酵与后发酵,紫娟红茶与普洱熟茶的花青素、儿茶素、茶多酚含量与抗氧化活性降低,但口感更甜醇。     

做青方式对凤凰单枞乌龙茶抗氧化特性的影响

研究做青方式对凤凰单枞乌龙茶的抗氧化特性的影响.结果表明,不同类型的乌龙茶对做青方式的响应不同,使得成茶中儿茶素含量变化不一致,表现出不同的抗氧化特性.采用机械摇青的重做青方式,降低了桂花香型乌龙茶茶汤中EGCG、EGC、C和ECG的含量,使茶汤的抗氧化特性减弱,表现为DPPH、O-2·、·OH自由基清除能力和对油脂过氧化物值抑制能力的下降;而机械作用方式对芝兰香型乌龙茶的儿茶素含量和抗氧化特性影响不大,芝兰香型凤凰单枞乌龙茶可采用机械做青的方式.     

不同发酵度茶叶的主要理化及香气成分分析

比较不同发酵度茶叶的理化及香气成分。测定绿茶、乌龙茶、红茶和藏茶的常规成分、活性成分;采用顶空固相微萃取(headspace solidphase micro-extraction,HS-SPME)结合气相色谱-质谱联用(gas chromatography-mass spectrometry,GC-MS)分析香气成分。4种茶样水分、灰分质量分数差异较小,绿茶水浸出物和蛋白质质量分数高于乌龙茶、红茶和藏茶,而粗纤维质量分数最低;红茶和藏茶中茶多酚和儿茶素的质量分数明显低于绿茶和乌龙茶,咖啡碱的质量分数稍高于绿茶和乌龙茶;绿茶中主要香气是醇类和烯烃类,红茶主要香气成分是酮类、醇类、酯类、醛类,藏茶中主要香气成分是酮类和酯类,乌龙茶中各香气成分检出量不多,分布相对平衡。     

轻重做青对凤凰单枞乌龙茶呈香物质的影响

研究轻重做青方式对凤凰单枞乌龙茶水浸出物和茶汤呈香物质等品质的影响.结果表明:与手工轻做青相比,采用机械重做青降低了鸟龙茶水浸出物中茶多酚和可溶性糖含量,但增加了咖啡碱和茶红素含量;机械重做青使茶汤的主体和特征香气组分和含量发生变化,主体香气组分的芳樟醇及其氧化物的含量降低4.01%,特征呈香物质3,7-二甲基-1,5,7-辛三烯-3-醇降低1.59%,水杨酸甲酯降低0.75%,α-紫罗酮降低0.42%,顺-3-己酸己烯酯增加2.81%,香叶醇增加2.65%,吲哚增加5.71%.乌龙茶汤主体和特征呈香组分及其含量变化不一致,导致的比例失调,可能是凤凰单枞乌龙茶不适合采用机械做青方式的主要原因.     

金萱品种夏暑茶类的生化成分分析及其抗氧化活性研究

本文对金萱品种不同茶类的夏茶与春茶、秋茶的生化成分含量及抗氧化能力进行了分析研究。结果表明:不同季节金萱绿茶中,夏茶的抗氧化能力最强,其茶多酚、儿茶素和酯型儿茶素的含量也最高;不同季节金萱乌龙茶中,夏茶的抗氧化能力最强,与金萱绿茶春茶的抗氧化能力相当,仅次于抗氧化能力最强的金萱绿茶夏茶,其茶多酚、儿茶素和酯型儿茶素的含量较低,茶多糖的含量则明显高于春茶和秋茶;不同季节金萱红茶的抗氧化能力差异不大。从不同茶类来看,金萱品种的茶叶的抗氧化能力表现为绿茶乌龙茶红茶。     

4种茶叶水提物及茶多酚的体外抗氧化性能研究

采用水提法对红茶、乌龙茶、绿茶和茉莉花茶进行提取,并对抽提物中总酚含量和各个儿茶素单体含量进行测定,通过常见的3种抗氧化能力测试方法,即DPPH法、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐[(2,2-azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid)diammonium salt,ABTS)]法及铁离子还原/抗氧化能力(ferric ion reducing antioxidant power,FRAP)法对4种茶叶水提物的体外抗氧化能力进行评价,同时比较茶多酚和VC的抗氧化活性。结果表明:4种茶叶水提物均有很强的体外抗氧化活性,绿茶、茉莉花茶、乌龙茶的DPPH法及FRAP法抗氧化活性测试结果优于红茶,红茶的ABTS+·清除率略高于其他3种茶。相关性分析结果显示儿茶素总量、总酚含量、没食子儿茶素(gallocatechin,GC)、表没食子儿茶素(epigallocatechin,EGC)、表没食子儿茶素没食子酸酯(epigallocatechin gallate,EGCG)、表儿茶素没食子酸酯(epicatechin gallate,ECG)含量和DPPH法、FRAP法结果呈现正相关,而与ABTS法结果呈现负相关。此外,试验结果表明茶多酚的抗氧化能力高于V_C。     

茶汤中抗氧化物活性对比研究

随机选取市售几种典型绿茶(碧螺春、高山绿茶)、乌龙茶(铁观音、肉桂、水仙)及红茶(正山小种、坦洋工夫)作为研究对象,比较各茶种茶粉的水浸提液与沸水冲泡茶叶而得的茶汤中的茶多酚含量;并测定茶汤的自由基清除活性(人工合成自由基DPPH·与ABTS~+·的清除活性)和体外还原活性(FRAP法测定其对三价铁的还原力)。试验结果表明,绿茶的茶粉浸提液与冲泡茶汤的茶多酚含量最高,茶汤的自由基清除活性与体外还原活性最强,乌龙茶次之,红茶最弱;这与其多酚含量呈正相关关系;而几种冲泡茶汤中,铁观音茶汤的茶多酚含量最少且体外抗氧化活力最弱,这应是源于茶叶包揉工艺的不同。另外,沸水冲泡茶汤较茶粉浸提液的茶多酚含量少,但仍具有很强的抗氧化活性,以日常沸水短时间冲泡的方式获得的茶汤为研究对象进行研究,对消费者进一步认识饮茶的健康功效具有更直接的指导意义。     

Retardation of lipid oxidation in blue sprat by hot water tea extracts

The blue sprat is a small fish belonging to the family Clupeidae. Deterioration of its freshness after catching is so rapid that the fish is cooked in simple ways and consumed locally. The prooxidant activity of the skin, dark meat and ordinary meat was much higher than that of other fishes such jack mackerel. Suppression of lipid peroxidation in blue sprat was attempted using hot‐water extracts of five types of Taiwanese tea with different degrees of fermentation, ie Longjing‐type green tea, Shy Jih Chuen oolong tea, Tungting oolong tea, Pouchong tea and black tea. All the tea extracts showed antioxidant activity on oxidation of linoleic acid induced by the extracts of blue sprat's tissues. The antioxidant activity of each tea extract showed a positive correlation with the contents of total catechins, especially with that of epigallocatechin gallate, but a poor correlation with the contents of total polyphenols. The Tungting oolong tea together with Chinese green tea effectively suppressed the prooxidant activities of the dark meat and skin of blue sprat. Impregnation of blue sprat in the extract of the Tungting oolong tea retarded the lipid oxidation in fish meat assessed by peroxide value and carbonyl value during refrigeration. Copyright © 2005 Society of Chemical Industry     

绿茶、桑叶和臭黄荆叶细粉水提液抑菌和抗氧化能力

探究绿茶、桑叶和臭黄荆叶3种植物干叶细粉水提液的抑菌和抗氧化能力。采用当量法测定3种原料中黄酮、多酚含量,二倍稀释法测定水提液对大肠杆菌、金黄色葡萄球菌的最小抑菌浓度和最小杀菌浓度,牛津杯法分析原料的抑菌活性。利用分光光度法研究3种水提液及其两两等比混合后的DPPH自由基清除率、羟自由基清除率和Fe2+螯合能力。结果表明,绿茶粉中水溶性黄酮、多酚含量最高,分别为62.22、133.82 mg/g,桑叶粉次之,臭黄荆叶粉最少。绿茶、桑叶和臭黄荆叶细粉在DPPH自由基清除率、羟自由基清除率和Fe2+螯合能力方面无协同作用,但黄酮、多酚含量与其抑菌和抗氧化活性间存在显著的量效关系(P<0.05)。因此,绿茶、桑叶和臭黄荆叶细粉水提液抑菌和抗氧化能力依次减弱,且三者抗氧化活性没有协同增效作用。     

Antioxidant and Anti-Inflammatory Properties of Lower-Polymerized Polyphenols in Oolong Tea

This study investigated the antioxidant and anti-inflammatory properties of the fractionated tea extract, a lower-polymerized polyphenol-rich extract ultrafiltrated from oolong tea. The amounts of total polyphenols, flavonoids and condensed tannin were enriched in fractionated tea extract compared to oolong tea. Furthermore, fractionated tea extract was a stronger scavenger of nitric oxide and 2,2-diphenyl-1-picryhydrazyl radicals than oolong tea. When lipopolysaccharide-treated RAW264.7 macrophages were co-incubated with both tea extracts (500 μg/mL) or (-)-epigallocatechin gallate (100 μg/mL) for 16 h, all samples (oolong tea, fractionated tea extract, and (-)-epigallocatechin gallate) suppressed nitric oxide production by 60, 48, and 46%, respectively, and the suppression was due to nitric oxide-scavenging. However, only fractionated tea extract lowered the proportion of phospholipid arachidonic acid and type II-cyclooxygenase expression, thereby decreasing PGE₂ synthesis by 29%. In conclusion, fractionated tea extract was rich in potent antioxidant substances capable of inhibiting the production of pro-inflammatory mediators.     

Beneficial effects of tea and its polyphenols against prostate cancer

Tea, next to water, is the most widely consumed beverage in the world. Depending upon the level of fermentation, tea can be categorized into three types: green (unfermented), oolong (partially fermented), and black (highly to fully fermented). In general, green tea has been found to be superior to black and oolong tea in terms of antioxidant and health promoting benefits owing to the higher content of (-)-epigallocatechin-3-gallate. Tea polyphenols comprise about one-third of the weight of the dried leaf, and they exhibit biochemical and pharmacological activities including antioxidant activities, inhibition of cell proliferation, induction of apoptosis, cell cycle arrest and modulation of carcinogen metabolism. Several studies demonstrate that most tea polyphenols exert their effects by scavenging reactive oxygen species (ROS) since excessive production of ROS has been implicated in the development of a variety of ailments including cancer of the prostate gland (CaP). Using cell culture and animal model systems, molecular targets for these remarkable beneficial effects of green tea drinking on CaP prevention and therapy have been defined. Geographical and case-control studies are showing that green tea drinking could afford CaP chemopreventive effects in human population. In this review we attempt to summarize the experimental as well as the epidemiological basis for the possible role of tea and its polyphenols for chemoprevention and chemotherapy of CaP.     

石榴皮提取物的抗氧化作用研究

分别以水、甲醇、丙酮和乙酸乙酯为溶剂,对石榴皮中的多酚进行了提取,得到4种提取物。采用油脂过氧化值(POV)法和二苯三硝基苯肼(DPPH)自由基法研究了提取物的抗氧化活性。结果显示,4种提取物均具有抗油脂过氧化和清除DPPH自由基的能力,其抗氧化活性随添加量的增加而增加。4种提取物中,丙酮提取物的抗油脂过氧化作用最大,其次为水提取物和甲醇提取物,乙酸乙酯提取物的抗油脂过氧化作用最小。当丙酮提取物添加量为猪油质量的0.1%时,其抗油脂过氧化活性接近添加量为0.02%茶多酚或BHT。4种提取物对DPPH自由基的清除能力大小顺序依次为:水提取物、丙酮提取物、甲醇提取物和乙酸乙酯提取物。浓度为0.0175 mg/mL的水提取物对DPPH自由基的清除率高达85.2%,高于BHT,但略低于茶多酚。石榴皮多酚是一种有效的天然抗氧化剂。     

ANTIOXIDATIVE ACTIVITY OF GREEN TEA POLYPHENOLS IN EDIBLE OILS

The antioxidant activity of green tea polyphenols in several edible oils and fried noodle was investigated. The green tea polyphenols consisted of 27.1% (−)-epigallocatechin-3-gallate, 19.3% (+)-gallocatechin, 16.7% (−)-gallocatechin-3-gallate, 16.1% (−)-epigallocatechin, 8.1% (−)-epicatechin-3-gallate, 7.5% (−)-epicatechin, and 5.2% (+)-catechin. The antioxidant effect of green tea polyphenols in lard and soybean oil was dose-dependent, but tocopherol was less effective. Compared to BHA and tocopherol, green tea polyphenols showed a stronger antioxidative activity on fish oil. Noodles were fried in lard containing green tea polyphenols at several concentrations. The oxidative stability of the noodle was proportional to the green tea polyphenol concentration in lard.     

Antioxidant activities of crude tea polyphenols, polysaccharides and proteins of selenium-enriched tea and regular green tea

The crude tea polyphenols, polysaccharides and proteins of regular green tea and Se-enriched green tea were investigated in vitro for antioxidant activities by auto-oxidation test (AAPH) and α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging method. Results showed that crude tea polyphenols of Se-enriched green tea provided the highest antioxidant activity by DPPH assay and the antioxidant activity was decreased in the order: crude tea polyphenols > crude tea proteins > tea polysaccharides. The crude protein of Se-enriched green tea was found to exhibit the highest antioxidant activity by AAPH method and the antioxidant activity was decreased in the order: crude tea proteins > tea polyphenols > tea polysaccharides. Tea polyphenols and tea polysaccharides of Se-enriched green tea presented significantly higher antioxidant activities than that of regular green tea. No significant difference of antioxidant activities was found between crude tea proteins of Se-enriched green tea and regular green tea. The combinations of Se with tea polyphenols and tea polysaccharides were responsible for the higher antioxidant activities of Se-enriched green tea than regular green tea.     

不同等级烘青绿茶生化成分及抗氧化能力的研究

：目的 研究3个不同等级烘青绿茶的生化成分、感官品质及抗氧化活性。方法 使用分光光度计测定3种茶样中总黄酮、茶多酚、氨基酸和咖啡碱的含量,利用清除二苯代苦味酰基自由基（1,1-dipheny-2-picryhydrazyl free radical, DPPH）法测定了其抗氧化活性,并进行感官评价。结果 3个等级绿茶总黄酮、茶多酚、氨基酸和咖啡碱含量差异显著（P＜0.05）,茶多酚随着茶样等级的降低而升高,咖啡碱的含量则相反,而氨基酸和黄酮是波动变化;不同等级绿茶的半抑制浓度（half maximal inhibitory concentration, IC50）差异显著（P＜0.05）,且IC50随着等级的降低而下降;感官评价得分随着等级的降低而降低;3种茶的抗氧化活性与其茶多酚含量成极显著正相关P＜0.01）,与咖啡碱的含量和感官审评得分呈极显著负相关（P＜0.01）。结论 3个等级的炒青绿茶抗氧化性随着等级的降低而升高,且与其主要生化成分呈显著相关。     

不同茶类陈年茶的生化成分分析及其抗氧化活性

本文研究了三个不同茶类陈年茶的生化成分及其抗氧化活性。采用比色法测定了这些茶样中水浸出物、茶多酚、总黄酮、可溶性总糖、游离氨基酸、茶黄素、茶红素及茶褐素的含量,同时采用高效液相色谱仪测定了这些陈年茶样中没食子酸、儿茶素单体及咖啡碱含量,采用FRAP法测定了其总抗氧化能力。结果显示不同茶类陈年茶样中主要品质生化成分含量相差较大,同一茶类不同品种或产地的陈年老茶样中主要品质生化成分含量也有差别。三个不同茶类供试茶样中EGC均未检出;陈年红茶样中GC和CG未检出;陈年乌龙茶样中GC和EGCG含量显著高于其他茶叶;陈年黑茶样中GA含量普遍较低,滇药香熟普砖茶中各儿茶素组分均未检出。不同茶类陈年茶样总抗氧化能力相差较大,其中以陈年千家寨生普散茶的抗氧化能力最强,且它的抗氧化活性与其茶多酚和儿茶素总含量呈浓度依赖关系。