四川茶树品种资源中EGCG3″Me研究

采用高效液相色谱法(HPLC)对四川70份茶树品种资源新梢中(-)-表没食子儿茶素-3-O(3-O-甲基)没食子酸酯(EGCG3″Me)含量进行分析,发现3份茶树品种资源富含EGCG3″Me(含量10 mg/g),即蜀茶5号、金观音、城西11号。对蜀茶5号新梢季节及叶位变化规律研究,发现春、夏、秋三季,随着新梢叶片成熟,EGCG3″Me含量均先增加后降低;同等叶位相比,EGCG3″Me含量均呈递增趋势;含量最高的叶位为秋梢第二叶,秋梢第一叶至第四叶均超过10 mg/g。以蜀茶5号秋梢加工成4种茶类,发现绿茶、黄茶中EGCG3″Me含量最高,与鲜叶相当,其次为青茶,而红茶中未检出,且萎凋显著增加其含量。建议四川富含EGCG3″Me茶叶将秋梢一芽二、三叶加工成绿茶或黄茶,且在加工前进行适度摊放(轻度萎凋)。     

不同茶叶中茶多酚类成分及咖啡碱含量研究

茶多酚含量决定着茶叶色香味及其保健功能。采用高效液相色谱法对绿茶、红茶、黄茶、青茶、白茶及黑茶6种品种中13种茶多酚的含量进行系统分析比较,并对5个不同产地绿茶、3个不同产地的红茶及2个不同产地的黑茶进行比较。结果表明,总茶多酚量与发酵度成反比;发酵度低的茶叶中酯型儿茶素含量显著高于发酵度高的茶叶;咖啡碱含量为福鼎白茶中含量最高,其次为恩施玉露。恩施玉露中茶多酚总含量显著高于其余绿茶;凤庆红茶中茶多酚总含量高于其余2种红茶;普洱茶茶多酚总含量显著高于安化黑茶。     

茶叶中的EGCG3″Me研究

设置茶鲜叶的不同采摘成熟度、不同采摘时间以及不同烘干温度等,制备茶样,研究不同成熟度、不同采摘时间以及不同烘干温度等对茶叶中表没食子儿茶素-3-O-(3-O-甲基)没食子酸酯(EGCG3″Me)含量的影响。研究发现,随着茶鲜叶成熟度的增加,叶片中EGCG3″Me含量有增加的趋势,一般在第3叶(或者第4叶)含量达到最高;1d中,茶鲜叶中EGCG3″Me含量在中午达到最高;在90℃烘干温度下,茶叶中的EGCG3″Me含量能得到有效的保持。     

3种梵净山茶营养成分分析

根据国家相关检测标准,以梵净山茶为研究对象,测定翠珠绿茶、金黔红红茶、梵针黑茶中主要营养成分、氨基酸含量、游离氨基酸含量、矿物质元素、重金属含量,比较3种梵净山茶的营养成分差异并对其营养价值进行了评价。试验结果表明:翠珠绿茶的维生素C含量较高为191.50 mg/100 g,梵针黑茶的还原糖和总糖含量较高分别达3.42%和7.24%,金黔红红茶的总糖含量较低;梵针黑茶的粗纤维含量最高达13.43%,3种梵净山茶的EAA/TAA的比值均大于40%,EAA/NEAA比值均大于60%,远超过WHO/FAO理想蛋白的标准模式;金黔红红茶游离氨基酸总量较高为2.167 g/100 g,翠珠绿茶茶氨酸含量较高为0.635 g/100 g;梵净山茶富含人体必需的微量元素,可作为人体补充矿物质元素的重要来源,其中翠珠绿茶的Fe、Se含量较高分别为674.76 mg/kg、7.56 mg/kg,金黔红红茶的Zn、Cu含量较高分别为116.95 mg/kg、77.90 mg/kg;重金属含量测定结果符合食品安全国家标准。     

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。     

六大茶类对部分肠道致病菌抑菌效果的研究

对比分析六大茶类的抑菌效果,探讨饮茶预防肠道病的可能性.采用倍比稀释法和牛津杯法,对绿茶、红茶、乌龙茶、黄茶、白茶和黑茶六大茶类抑制肠道致病菌大肠埃希氏菌和金黄色葡萄球菌的作用进行测定.结果显示,6种茶的水浸液在浓度24mg/mL对金黄色葡萄球菌均有抑菌作用;在浓度48mg/mL对大肠杆菌均有抑菌作用,且浓度越高,抑制作用越强;绿茶、乌龙茶、黄茶、白茶水浸液在低于饮用浓度(6mg/mL)对金黄色葡萄球菌仍有抑菌作用;六大茶类中,以绿茶水浸液的抑菌效果最好,红茶的最差,黄茶、白茶的抑菌效果优于黑茶和红茶.说明六大茶类对肠道致病菌均有抑菌效果,抑菌效果与其内含成分有关.     

基于RAW264.7细胞模型的不同茶类抗炎功能特性

茶叶根据经典加工工艺不同分为红茶、绿茶、青(乌龙)茶、白茶、黄茶、黑茶。为探讨不同加工工艺形成的不同茶类的抗炎功能特性,本研究以云南大叶种绿茶、红茶、普洱黑茶、金观音乌龙茶、福鼎大白白茶、君山银针黄茶为材料。采用硝普化钠法和脂多糖诱导RAW264.7巨噬细胞为体外炎症模型评价抗炎活性。结果发现,绿茶、白茶及黄茶对一氧化氮(NO)的清除能力较强,半抑制浓度(IC50)值在99.27~104.83μg/m L范围内;在六种茶类中,黄茶对脂多糖诱导RAW264.7细胞产生炎症反应的抑制作用最强,其抑制NO产生的IC50值为398.13μg/m L,在浓度为500μg/m L时,其对肿瘤坏死因子α(TNF-α)和白介素6(IL-6)的抑制率分别为69.25%、87.68%;黄茶可在基因转录和翻译水平上,显著下调i NOS基因的转录和翻译。相关性分析表明,茶多酚含量与清除NO的IC50值、抑制细胞产生NO的IC50值、TNF-α以及IL-6产生量均呈显著负相关。表明六种茶类均具有抗炎活性,黄茶对促炎症因子(NO、TNF-α、IL-6)的抑制效果最佳,可通过下调i NOS基因的转录和翻译水平,减少NO产生,从而发挥抗炎功效。     

相同加工原料下六大茶类抑菌效果比较

为探讨相同加工原料下六大茶类的抑菌效果,以春季碧香早的1芽2叶茶鲜叶为原料,将其固定及分别加工成绿、黄、黑、白、青、红六大茶类,采用牛津杯法比较研究7个样品对金黄色葡萄球菌(Staphylococcus aureus)、枯草芽孢杆菌(Bacillus subtilis)、大肠杆菌(Escherichia coli)3种细菌以及黑曲霉(Aspergillus niger)、啤酒酵母(Saccharomyces cerevisiae)2种真菌的抑菌活性,并利用96孔细胞板及二倍稀释法检测7个样品的最低抑菌浓度(MIC)与最低杀菌浓度(MBC)。结果表明:7个样品对3种细菌均有抑制作用,对2种真菌的抑制效果不明显;7个样品对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌的抑菌圈大小均呈现出固定样绿茶黄茶黑茶青茶白茶红茶的特性,最低抑菌浓度呈现出红茶青茶、白茶黑茶、黄茶、固定样、绿茶的特性,最低杀菌浓度均呈现出红茶青茶、白茶、黑茶、黄茶固定样、绿茶的特性;绿茶和其他茶类之间、红茶和其他茶类之间的抑菌效果有显著性差异(P0.05)。     

茶道养生的辩证法则

法则一、辨茶性以明养生之道 众所周知,茶叶有绿茶、红茶、青茶、黄茶、白茶、黑茶等六大基本茶类,不同品种的茶叶,其性气也不尽相同（因品种、产地、制作加工方法的差异所致）,故而保健之功效,也就不尽相同。例如经过发酵制成的红茶,其性气就和绿茶等品种不同,而略偏于温。但总体说来,凡茶叶,     

6种茶类多酚含量测定及其抑菌活性

目的测定绿茶、黄茶、白茶、青茶、红茶、黑茶中多酚的含量,研究其抑菌活性。方法针对6种茶叶样品采用超声波提取法,并经乙酸乙酯提取后,所得供试品溶液依国标法测定多酚含量。并以大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、蜡样芽孢杆菌为实验菌株,通过圆形滤纸片扩散法研究不同浓度供试品溶液的抑菌活性。结果 6种茶叶样品乙酸乙酯部位多酚得率分别为绿茶59.07%、黄茶62.39%、白茶32.15%、青茶50.70%、红茶34.86%、黑茶40.68%。对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、蜡样芽孢杆菌的抑菌效果均与供试品溶液浓度呈正相关。结论 6种茶发酵程度的差异导致所含成分不同,致使其抑菌活性有明显区别。     

The development of a suitable manufacturing process for ‘Benifuuki’ green tea beverage with anti‐allergic effects

Epigallocatechin‐3‐O‐(3‐O‐methyl) gallate (EGCG3″Me) has been reported to inhibit type I allergy better than epigallocatechin gallate (EGCG), a major catechin in tea leaves (Camellia sinensis L). We examined the effects of extraction and sterilization on the catechin content and histamine release from mast cells, as a representative reaction of early phase allergy, in the manufacture of ‘Benifuuki’ green tea beverage. Among various varieties of tea, the cultivar ‘Benifuuki’ contains approximately 2% of EGCG3″Me. Ester‐type catechins and their epimers increased with the increased extraction temperature of the tea. A tea infusion, extracted at 90 °C, strongly inhibited histamine release from mast cells. Furthermore, sterilization affected the catechin content in the manufactured green tea beverage. Sterilization at high temperature promoted the isomerization of catechins and the sterilized green tea beverage had a strong inhibitory effect. When EGCG3″Me, EGCG, epicatechin‐3‐O‐gallate (ECG) and their epimers, GCG3″Me (gallocatechin‐3‐O‐(3‐O‐methyl) gallate), GCG (gallocatechin‐3‐O‐gallate) and CG (catechin‐3‐O‐gallate) were compared, the anti‐allergic effect of GCG3″Me was strongest, and the order of activity was GCG3″Me > EGCG3″Me > GCG > EGCG. We consequently suggest that it was necessary to extract components from tea at the highest temperature possible, and to pasteurize under retort conditions (118.1 °C, 20 min), to manufacture functional green tea beverage with an anti‐allergic action. Copyright © 2005 Society of Chemical Industry     

广东本地产茶叶矿物质元素与茶多酚含量调查分析

目的 调查广东省当地种植的茶叶矿物质元素和茶多酚含量范围、成分差异及分布特征.方法 采集2017-2018年广东省7个茶叶产区具有代表性的茶叶(绿茶、乌龙茶、红茶)样品,按照国标法对样品中的9种矿物质元素和茶多酚的含量进行测定,对比分析不同种类、不同产区中矿物质元素和茶多酚的含量差异.结果 乌龙茶中钾元素的平均含量为1...     

Effect of consecutive steeping on antioxidant potential of green,oolong and black tea

After water, tea is considered to be one of the most consumed drinks worldwide. To get the maximum benefit from the whole‐leaf teas, the manufacturers provide instruction that these teas can be steeped 2–3 times over 6–8 h. In this study, the effect of consecutive steeping on radical‐scavenging ability of whole leaf green tea (unfermented), oolong tea (partially fermented) and black tea (fully fermented) was determined. Green tea showed the highest level of antioxidant activity, total phenolic and flavonoid content followed by oolong tea and black tea irrespective of the number of steeping done. The result also demonstrated that re‐steeping reduced the antioxidant potential of teas. Moreover, it was revealed that green tea is the best candidate for re‐steeping followed by oolong and then black tea.     

乌龙茶粗多酚、EGCG和EGCG3’’Me体外抑制α-葡萄糖苷酶活性

为研究乌龙茶粗多酚、表没食子儿茶素没食子酸酯((-)-epigallocatechin gallate,EGCG)、甲基化EGCG(epigallocatechin3-O-(3-O-methyl)gallate,EGCG3’’Me)对α-葡萄糖苷酶活性的抑制作用,采用酶动力学和紫外吸收光谱方法,探究并比较了三者的抑制活性及类型。结果表明:乌龙茶粗多酚、EGCG和EGCG3’’Me对α-葡萄糖苷酶均有较强的抑制作用,半抑制浓度(half inhibitory concentration,IC50)依次为0.178、0.040、0.064 mg/m L;Lineweaver-Burk双倒数作图显示乌龙茶粗多酚和EGCG的抑制类型为非竞争抑制,而EGCG3’’Me为竞争性抑制;紫外吸收光谱实验表明乌龙茶多酚样品能够使α-葡萄糖苷酶的吸收光谱发生蓝移,推测酶蛋白的构象有所变化。EGCG与EGCG3’’Me对α-葡萄糖苷酶活性的影响和抑制类型的不同可能是由于EGCG的一个羟基被甲氧基取代所引起的。     

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     

Fluoride in tea from Shandong Province,China and exposure assessment

ABSTRACT

In this study fluoride in 170 tea samples from Shandong province (China) was determined using a selective ion electrode. The fluoride concentrations ranged from 31.2 to 338 mg/kg with an average of 119 mg/kg. The mean fluoride concentrations were 164, 121, 98.7 and 96.8 mg/kg, which corresponded to Pu’erh tea, green tea, oolong tea and black tea, respectively. Moreover, 4.7% of the analysed samples exceed the legal limit of 200 mg/kg recommended by China. The estimated daily intake of fluoride via drinking tea for an adult was between 0.655 and 1.07 mg/person/day, which were lower than the provisional maximum tolerable daily intake value of 3.5 mg/person/day set by the National Health and Family Planning Commission of the People’s Republic of China. In future, maintaining a surveillance programme to monitor the trend of fluoride in tea is necessary for food safety and human health.     

Determination of flavonols in green and black tea leaves and green tea infusions by high-performance liquid chromatography

Tea flavonols are potent antioxidants and make up 2–3% of the water-soluble solids from tea leaves. In this paper, the conditions necessary for hydrolysing and analysing flavonols in tea leaves and tea infusions are optimised and an isocratic elution system for the determination of the hydrolysed flavonols by high-performance liquid chromotography is presented. Aqueous ethanol was selected as the best solution for hydrolysing flavonoids in tea leaves. The contents of flavonols on a dry weight base in green tea leaves ranged from 0.83–1.59, 1.79–4.05, and 1.56–3.31 g/kg, and in black tea leaves from 0.24–0.52, 1.04–3.03, and 1.72–2.31 g/kg for myricetin, quercetin, and kaempferol, respectively. It was observed that the particle size of ground tea leaves significantly influenced the yield of flavonols. The contents of flavonols in different green tea infusions are given.     

Effects of tea leaf waste of green tea,oolong tea,and black tea addition on sudangrass silage quality and in vitro gas production

This study evaluated the fermentation characteristics and in vitro gas production of sudangrass (Sorghum sudanese) silage with tea leaf waste of green tea, oolong tea and black tea added. All types of tea leaf waste contain large amounts of nitrogen (N) and tannins, and a small amount of low‐water‐soluble carbohydrates. Sudangrass was preserved without (control) and with green tea waste (GTW), oolong tea waste (OTW) or black tea waste (BTW) at rates of 50, 100 and 200 g kg^?1 fresh matter in laboratory silos. The pH and butyric acid levels were significantly lower in GTW at all rates and in OTW at the 200 g kg^?1 rate, whereas those levels were high in the control and BTW‐treated silage. Lactic acid level was appreciably higher in GTW‐ and OTW‐treated silage than the control and BTW‐treated silage. The addition of all types of tea waste increased the total N and tannins of the silage, whereas the acid detergent insoluble N was increased in the OTW‐ and BTW‐treated silage. GTW treatment increased gas production within a 96‐h period compared with the control, whereas OTW and BTW additions at 200 g kg^?1 rates caused lower gas production. It is concluded that the fermentation characteristics and feed value of the silage incorporating with tea leaf wastes are different for these types of tea leaf. Among the three kinds of tea waste, GTW is the most valuable material as a silage additive. Copyright © 2004 Society of Chemical Industry     

Comparison of the relative dissipation rates of endosulfan pesticide residues between oolong and green tea

The dissipation behaviour of endosulfan in dry made-tea leaves of oolong and green tea was compared to establish whether there was any difference in dissipation rates between the two teas. The dissipation of endosulfan in oolong and green tea corresponded with a first-order kinetics curve. The average half-life of endosulfan (n = 12) was 1.60 ± 0.44 days in green tea and 2.01 ± 0.55 days in oolong tea, showing a statistically significant difference, and indicating that the dissipation of the pesticide was significantly slower in oolong tea than that in green tea. Although the initial levels of residual endosulfan were lower in oolong tea, due to the slower dissipation rate, the residues 5-7 days after application were higher in oolong than in green tea. It is suggested that the minimum interval between endosulfan application and tea leaf harvesting is 7 days for green tea and 10 days for oolong tea in the case where the maximum residue limit of endosulfan in made-tea is fixed as 10 mg kg^-1.     

Comparison of catechins and volatile compounds among different types of tea using high performance liquid chromatograph and gas chromatograph mass spectrometer

As tea is one of the most popular beverages consumed worldwide, it is important for customers and business investigators to develop an easy and reliable method to discriminate between different types of teas from each other. A total of eighty‐seven types of various white, green, oolong, black and Puer teas were collected from the major tea estates in China, and their catechin contents and volatile compounds were compared by high performance liquid chromatograph and gas chromatograph mass spectrometer. It was found green tea contained the highest concentrations of total catechins, (?)‐epicatechin gallate (ECG) and (?)‐epigallocatechin gallate (EGCG), while oolong teas contained the highest concentrations of (?)‐epigallocatechin (EGC) among these five types of teas. The aroma composition and their quantities in different types of teas varied quite widely. The concentration of ECG, EGCG, pentanal, hexanal, methyl jasmonate, indole, (E,E)‐2,4‐hexadienal and 1,2,3‐trimethoxybenzene was shown to be different and could be used to discriminate white, green, oolong, black and Puer teas. The result showed that different types of teas could be partially classified by cluster analysis using index of individual catechins and volatile components.