茶树叶片中茶皂素提取工艺优化

以夏季茶树老叶为原料,利用乙醇水溶液提取茶皂素,考察液料比、乙醇体积分数、浸提温度和浸提时间对粗提物中茶皂素含量及茶叶中茶皂素得率的影响。单因素试验结果表明,液料比10︰1(mL/g)、乙醇体积分数70%、浸提温度60℃和浸提时间1.5 h时为宜。通过正交试验确定了茶皂素提取的最佳工艺:液料比20︰1(mL/g)、乙醇体积分数60%、浸提温度70℃、浸提时间2 h。试验结果为夏秋茶资源中茶皂素的提取提供参考。     

Partial Purification And Characterization Of Polyphenoloxidase From Turkish Tea Leaf (Camellia Sinensis L.)

Polyphenoloxidase was isolated from tea leaf, Camellia sinensis (L.) O. Kuntze grown in Turkey and its biochemical characteristics were studied. Polyphenoloxidase was extracted and partially purified by ion-exchange chromatography on a column packed with diethyaminoethyl cellulose. The optimum temperature and pH of polyphenoloxidase were found to be 30^oC and 6.0, respectively. Heat stability of tea leaf polyphenoloxidase decreased as the temperatures increased from 30 to 80^oC. Tea leaf polyphenoloxidase contained several phenolic compounds as substrate and sensitive to inhibitors such as ascorbic acid, cysteine, oxalic acid, and citric acid.     

铝对氟在茶树体内吸收与分配的影响

为了探讨铝(Al3+)对茶树吸收氟(F)的累积特性,研究溶液培养条件下,不同浓度Al3+及c(Al3+):c(F－)比例对茶树吸收富集F的影响。结果表明：低浓度Al3+ (1.05～5.26mmol/L,c(Al3+):c(F－)=1:10～1:2)促进了F在茶树根部的富集,主要以F离子态形式被茶树吸收;而高浓度Al3+ (10.52～31.57mmol/L,c(Al3+):c(F－)=1:1～3:1)抑制了F在茶树根部的富集,主要以Al/F络合态形式被茶树吸收。不同浓度Al3+促进了F在茶树叶部的富集。培养液中c(Al3+):c(F－)≥1时(c(Al3+)≥10.52mmol/L),抑制了茶树根部对F的吸收富集,而c(Al3+):c(F－)＜1时(c(Al3+)≤5.26mmol/L),促进了茶树根部对F的吸收富集。Al3+促进了茶树体内F向地上部分转移,尤以c(Al3+):c(F－)为1:1、1:3、1:5时,F从茶树根部向地上部分转移系数最高。     

茶多糖的分离纯化及其抗凝血活性

为了研究茶多糖不同组分对抗凝血活性的影响,通过水提醇沉的方法对茶多糖进行提取,经聚酰胺柱脱色、脱蛋白,采用离子交换柱DEAE Sepharose CL-6B对多糖进行分离纯化,用高效凝胶渗透色谱测定其分子量,并对多糖组分抗凝血活性进行了研究。结果表明:聚酰胺法脱色、脱蛋白效果较好,脱色率、蛋白去除率和多糖保留率分别为75.1%、91.2%和79.2%;经纯化后得到4个组分,分别为TPS-1、TPS-2、TPS-3和TPS-4;HPGPC法测定TPS-1、TPS-2和TPS-3分子量分别为20760、24230和250643,为均一多糖,TPS-4含两个组分,其分子量分别为689 113和4 150,为非均一多糖。体外抗凝血实验显示TPS-4能延长活化部分凝血活酶时间(APTT)和凝血酶时间(TT),说明是通过内源性途径来影响凝血的。     

茶叶籽中黄酮的分离及HPLC-MS联用分析

用大孔吸附树脂HPD826分离纯化茶叶籽总黄酮的粗提物,对影响HPD826树脂动态吸附、解吸的各因素进行系统研究。最终确定最佳条件为：上样液质量浓度1.8 mg/mL、上样速率2 mL/min、体积分数50%乙醇作为洗脱剂、洗脱剂流速1 mL/min。纯化后的茶叶籽黄酮纯度为40.81%,比纯化前提高了7.63 倍。通过高效液相色谱-质谱联用分析大孔吸附树脂纯化后样品,初步确定茶叶籽中4 种黄酮的结构,均为柚皮素的多糖苷。     

云南大叶种晒青毛茶提取物对产毒黄曲霉生长及产毒的影响

普洱茶在发酵过程中,微生物组成十分复杂,尤其是黑曲霉等霉菌起到主要作用,因此一些消费者担心普洱茶在发酵过程中受到黄曲霉毒素(AFS)的污染。本文通过测定菌落直径、孢子萌发及菌丝体干重等方法研究云南大叶种茶提取物对产毒黄曲霉AS3.4408生长的影响;采用紫外荧光法和HPLC法研究云南大叶种茶提取物对产毒黄曲霉AFS生物合成的影响;并将产毒黄曲霉AS3.4408接种到云南大叶种茶叶中,检测茶叶中的AFS含量,以求对普洱茶的安全性进行评估。研究表明,云南大叶种茶提取物对产毒黄曲霉AS3.4408菌落的生长及产毒均具有显著的抑制作用,且存在明显的剂量依赖关系;将产毒黄曲霉AS3.4408接种到云南大叶种茶叶中,菌株生长良好,但茶叶基质经HPLC检测,未检测到黄曲霉毒素B1、B2、G1和G2,表明云南大叶种茶中的某种(些)成分对黄曲霉毒素的生物合成具有抑制作用。     

蒸汽爆破预处理对油茶籽水代法提油品质的影响

利用蒸汽爆破对油茶籽进行处理,探究不同蒸汽爆破压力、维压时间对油茶籽油提油率、油品理化性质、活性物质含量变化的影响,并分析影响其品质变化的内部因素。结果表明：当蒸汽爆破压力在0～1.6 MPa时,油茶籽油提油率随着压力的升高而增加,超过1.6 MPa时,提油率下降;当维压时间为30 s时,提油效果优于其他处理时间;因此蒸汽爆破处理最佳条件为1.6 MPa处理30 s。蒸汽爆破处理可以降低油茶籽油的酸价、过氧化值,提高油茶籽油的碘值、多酚质量浓度和角鲨烯、VE含量。经汽爆处理的油茶籽表面变得粗糙,结构遭到破坏,进而有利于油茶籽油和活性物质的释放。蒸汽爆破处理加速了油茶籽油美拉德反应的发生。因此,蒸汽爆破预处理有利于油茶籽油的提取和活性物质的释放。     

冲泡条件对日照绿茶茶多酚得率的影响

为探究不同冲泡条件对绿茶茶多酚得率的影响,该文选取山东省日照市产地绿茶,首先对冲泡温度、冲泡时间和料液比进行单因素试验,分别得到各因素的最佳条件,然后采用正交试验设计,探究3个因素对日照绿茶茶多酚得率的影响.结果显示,当温度在60℃～80℃时,茶多酚得率随着冲泡温度的升高而提高,当温度在90℃～100℃时,茶多酚得率随...     

油茶籽油对大鼠降血脂和预防脂肪肝的影响

目的:考察油茶籽油辅助降血脂和预防脂肪肝的作用。方法:采用SD大鼠,预饲养4d后随机分成6组(每组10只):A.高脂对照组、B.空白对照组、C.高剂量茶籽油组、D.中剂量茶籽油组、E.低剂量茶籽油组、F.橄榄油对照组;各组每kg体质量的日喂食标准为:A.150g高脂饲料和9.0g生理盐水,B.150g基础饲料和9.0g生理盐水,C.150g高脂饲料和9.0g油茶籽油,D.150g高脂饲料和3.0g油茶籽油,E.150g高脂饲料和1.5g油茶籽油,F.150g高脂饲料和9.0g橄榄油,并以高脂饲料建立高脂模型;连续饲养7周后杀鼠,制备血清以备测定其甘油三酯(TG)、总胆固醇(TC)和高密度脂蛋白胆固醇(HDL-C)含量,并取肝脏进行病理切片、观察其脂肪病变程度。结果:与高脂对照组比较,3个剂量茶籽油组大鼠血清的TG和TC水平均极显著地降低(P<0.01);3个剂量茶籽油组大鼠肝脏的脂肪病变程度明显轻于高脂对照组(P<0.05),其中,高剂量组与橄榄油组类似,即:90%病例为正常肝或轻度脂肪肝,仅10%病例为中度脂肪肝,而且均与空白组的表现接近。结论:油茶籽油具有辅助降血脂作用以及预防脂肪肝的作用。     

营养盐加量对酵母发酵的影响初探

研究了玉米淀粉浆在不同添加比例的营养盐1#、2#、3#、4#、5#液化、糖化,在发酵22h、46h、60h进行发酵试验对比,将能使酵母生长状态好,酵母数多、出芽率高、产酒率高的样品应用到生产中。     

Effect of Gibberellins on Chemical Composition and Quality of Tea ( Camellia sinensisL)

The effect of gibberellins on tea leaf chemical composition and quality was investigated. The results showed that application of gibberellins was beneficial to green tea quality. Content of amino acids increased by 9·8% and that of vitamin C by 17·8% and tea catechins index increased by 12·9%. The content of tea polyphenols and ratio of tea polyphenols to amino acids decreased by 9·9% and 11·5%, respectively. Differences of all the indicators were statistically significant (P<0·05). Quality scores of the treated leaf increased significantly (P<0·05). It was also revealed that tea plant response to gibberellins was dependent not only on genetics, but also on shoot development stage.     

Effect of extraction temperature on cream and extractability of black tea [Camellia sinensis (L.) O. Kuntze]

Summary Tea cream and haze in black tea infusions increased with the rise in the tea extraction temperature. The temperature at which substances involved in cream and haze formation began to be extensively extracted into the tea infusion was between 50 and 60 °C. The tea cream particle volume concentration in infusions extracted at 50 °C or below formed less tea cream particles, and their particle sizes were larger and more heterogeneous than those extracted at 60 °C and second infusions extracted at 90 °C from the residual leaves that were previously extracted at 40–50 °C. High‐performance liquid chromatography confirmed that constituents with pyrogallol groups are involved in tea creaming, and the effect of caffeine on tea cream and haze depends on whether these constituents are sufficiently present. The extractability of tea increased with the rise in extraction temperature. Two‐stage extraction of tea in ready‐to‐drink tea processing and its effects on colorimetric indicators were also examined.     

茶叶籽中总黄酮的提取及结构的初步鉴定

研究茶叶籽中总黄酮的提取工艺,在单因素实验基础上,选取液料比、提取温度和乙醇体积分数3个影响因素,以总黄酮含量为评价指标,通过Box-Benhnken的中心组合设计原理和响应面分析法优化提取工艺,确定最佳提取条件为:液料比26∶1(mL∶g),乙醇体积分数58%,提取温度82℃,提取时间2h,茶叶籽中总黄酮含量为11.174mg/g。通过颜色反应和紫外光谱特征,初步鉴定茶叶籽黄酮为二氢黄酮类化合物。     

Isolation and chemical characterisation of a polysaccharide from green tea (Camellia sinensis L.)

BACKGROUND: To contribute towards understanding the relationship of structure and bioactivity, a protein‐bound acidic polysaccharide named TPC3‐1 was isolated and purified from low‐grade green tea (Camellia sinensis L.). The homogeneity and weight average molecular weight of TPC3‐1 was determined by agarose gel electrophoresis and high‐performance gel permeation chromatography. The monosaccharide and amino acid composition of TPC3‐1 were analysed by gas chromatography and an amino acid analyser. The molecular structure of TPC3‐1 was characterised by Fourier transform infrared spectroscopy, ¹³C nuclear magnetic resonance spectroscopy and atomic force microscopy. RESULTS: Based on the data obtained, the average peak molecular weight of TPC3‐1 was about 120 kDa. TPC3‐1 was composed of L ‐arabinose, D ‐ribose, D ‐xylose, D ‐glucose and D ‐galactose with a molar ratio of 4.9:2.2:3.1:1.8:1.0. Fifteen amino acids were identified as components of the polymer. The TPC3‐1 molecule was found to have an anomeric carbon sign of both α and β configurations and high‐branched chains. The network structure of TPC3‐1 was observed. CONCLUSION: The tea polysaccharide TPC3‐1 was an acid protein‐bound polysaccharide with an image of network structure. The results presented here will facilitate further study of the relationship between the chemical structure and biological role of tea polysaccharide. Copyright © 2008 Society of Chemical Industry     

Effect of Maofeng tea processing on leaf trichomes of tea (Camellia sinensis L)

Scanning electron microscopy was used to investigate the ultrastructure of trichomes on Maofeng, a special Chinese green tea. The trichomes were cylindrical in appearance with a length of 0.6–1 mm, wall thickness of 0.2–0.3 μm and a mid-point diameter of 9–10 μm. The angles between the trichomes and the leaf under-surface were below 30° in Maofeng tea though they were 45–75° in fresh green leaf. The trichome wall consisted mainly of fibre and its outer-surface was unevenly covered with waxy substances and striped. The trichome joint, by which the trichome was attached to the leaf tower epidermis, was expanded and filled with essential oil droplets. The undeveloped trichomes assumed a flattened form because of the action of pressing during rolling and shrank during the tea drying process. During the Maofeng tea processing, trichome shedding was caused by disruption of its expanded joint structure and breakdown at the cylindrical wall above the expanded joint.     

Lead contamination in different varieties of tea plant (Camellia sinensis L.) and factors affecting lead bioavailability

BACKGROUND: There has been increasing concern in recent years about the concentration of lead (Pb) in tea. However, little research has been done to address questions concerning the distribution of Pb in different varieties of tea plant and the differences among tea plant varieties in their uptake and accumulation of Pb from the soil. Therefore the aim of this study was to investigate the accumulation of Pb in different tea plant varieties and the factors affecting Pb bioavailability. RESULTS: Three patterns of Pb distribution could be observed in different plant parts among the eight tea varieties surveyed, as well as a linear relationship between the Pb concentration in fine roots and the exchangeable Pb fraction in the corresponding soil. The uptake of Pb by fine roots increased significantly as the soil pH decreased. The average ratios of Pb concentration in fine roots to those in young stems and young leaves were 5.18 and 31.80 respectively. In fine roots the Pb concentration varied from 22.7 to 61.6 mg kg^?1. CONCLUSION: The results indicated that the uptake, transport and accumulation of Pb by tea plant organs were strongly governed by soil conditions and tea variety, thus providing tea producers with useful information on variety selection for the production of quality teas containing low levels of Pb. Copyright © 2010 Society of Chemical Industry     

中国红茶产销现状与发展前景

回顾了我国和世界其它国家红茶产销情况,分析了我国红茶产销的优劣势,并对我国红茶产业发展前景予以展望,提出了我国红茶产业的发展对策。     

The authenticity identification of teas (Camellia sinensis L.) of different seasons according to their multi-elemental fingerprints

The objective of this study was to investigate the feasibility of discriminating harvest seasons of tea by the multi-elemental fingerprinting technique. A total of 162 tea leaf samples were collected in spring, summer and autumn of 2015 and 2016 respectively. The concentrations of 25 elements were determined by inductively coupled plasma mass spectrometry. Analysis of variance and linear discriminant analysis were performed to analyse the differences of tea leaves of different harvest seasons and years and identify the seasons and years of tea leaves. The results showed that tea leaves of different harvest seasons and years had their own elemental profiles. For tea leaves of 2015 and 2016, using the established discriminant models, the total accuracy of season-based identification reached 95.1% and 87.7% respectively. The classifications of tea leaves of different years were 100% accurate. Therefore, the multi-elemental fingerprinting technique can be used to identify harvest seasons of tea.