Chemical Constituents of Pu-erh Tea and Its Inhibition Effect on α-amylase in vitro

[Objective]The aim was to clarify the chemical substance basis of hypoglycemic and lipid-lowering effects of Pu-erh Tea. [Method]Pu-erh Tea was extracted with 95% ethanol,followed by petroleum ether,chloroform,ethyl acetate and n-butanol extraction,after the further purification and through the NKA-9 macroporous resin and many times of Sephadex column chromatography,two compounds were isolated,in the same time,the effect of Uracil and Gallic acid on α-amylase was studied. [Result]The Uracil and Gallic acid were isolated and identified respectively from Pu-erh Tea and the Uracil was firstly isolated from Pu-erh Tea; Gallic acid had strong inhibition on α-amylase. [Conclusion]It could provide some theories on the hypoglycemic and lipid-lowering effects of Pu-erh Tea.

Study on Pu-erh Tea Methanol Extracts on Antibacterial Activity of Several Plant Pathogens

[Objective] The aim was to study Pu-erh tea methanol extracts on antibacterial activity of several plant pathogens and provide reference for application of Pu-erh tea in agriculture disease prevention and control.[Method]The inhibitive effect of Pu-erh tea methanol extracts on several plant pathogens was studied by adopting mycelium growth rate method.[Result] The results showed that Pu-erh tea methanol extracts had inhibitive effects on Thanatephorus cucomeris(Frank)Donk,Fusarium oxysporum f.sp.niveum,Fusa...

Analysis of α-amylase Inhibitor Content Change in Pu-erh Tea During Pile-fermentation Process

The study was to investigate the changes of α-amylase inhibitor content in Pu-erh tea during pile-fermentation process. Pu-erh tea samples from two regions of Shuangjiang County and Jinggu Dai and Yi Autonomous County of Yunnan Province at various fermentation stages were used as experimental materials to investigate the effect of different fermentation stages on the inhibitory effect to α-amylase; and the change law of the inhibitory effect of c-amylase inhibitor during processing was meanwhile studied by determining the contents of tea polyphenol and amino acid. The results showed that crude meterial of Pu-erh tea presented strong inhibitory effect to α-amylase; this inhibitory effect assumed a de： creasing trend to the minimum at the middle stage of fermentation, whereafter it increased to some extent. Made tea also showed a strong inhibitory effect to α-amylase. During whole processing period, contents of tea polyphenol and amino acid generally assumed a remarkably decreasing trend. Our results provided references for further isolating co-amylase inhibitor from Pu-erh tea and discussing the mechanism of its health care function.

Factors Influencing the Effects of Theabrownin in Pu-erh Tea on Scavenging DPPH Radicals

[Objective] This study aimed to explore factors influencing the effects of theabrownin in Pu-erh tea on scavenging DPPH radicals. [Method] Taking Pu-erh tea as main research object, theabrownin in Pu-erh tea from tea piles with different times of mixture, stored for different years and processed by both the old and new techniques were extracted and isolated. And DPPH method was used to study the effects of theabrownin solution and tea liquor on scavenging radicals and their antioxidant activity. [Result] The result showed that the theabrownin content in Pu-erh tea from tea piles with one to four times of mixture revealed a first declining and subsequently rising trend. Under different pH conditions, the rates of DPPH radical scavenging of 1 mg/ml theabrownin solution made from tea piles with different times of mixture decreased gradually with the increase of pH, and all the rates were lower than that of the control vitamin C solution; the rates of DPPH radical scavenging of theabrownin from tea samples stored for different years and produced by different techniques dropped slowly within pH range 3.0-6.0; when pH was higher than 6.0, the rates of DPPH radical scavenging of theabrownin from tea samples produced by both new and traditional techniques in 2001 declined obviously, while the declining trend was not obvious in either the black tea or the Pu-erh tea produced by new technique in 2005. Under different theabrownin concentrations, the rates of DPPH radical scavenging of theabrownin solution made from tea piles with different times of mixture ascended as the concentration increased and the highest rate occurred in tea pile with four times of mixture, reaching up to 46.56%±0.88%; for tea samples stored for different years and produced by different techniques, the rates of DPPH radical scavenging of theabrownin rose gradually with the increase of the theabrownin concentration; the rate of radical scavenging of theabrownin in the black tea ascended obviously and that in Pu-erh tea was decreasing within the concentration range of 0.04 -0.06 mg/ml. At pH6.0, the DPPH radical scavenging ability of theabrownin in 0.1 mg/ml theabrownin solution and tea liquor containing 0.1mg/ml theabrownin from tea piles with different times of mixture ascended with the time of mixture; solution made from tea samples produced by different techniques in different years, the DPPH radical scavenging ability of theabrownin solution and tea liquor followed： Pu-erh tea produced by the new technique in 2001 ﹥ Pu-erh tea produced by the old technique in 2001﹥ Pu-erh tea produced by the new technique in 2005. And the DPPH radical scavenging ability of theabrownin in tea liquor containing 0.1 mg/ml theabrownin was higher than that in 0.1 mg/ml theabrownin Solution made from tea samples either with different times of mixture or produced by different techniques in different years. The above results indicated that many factor influenced the effects of theabrownin on eliminating DPPH radicals, including the time of fermentation, fermentation technique, years of storage, concentration and pH all had great influence on the effects of theabrownin on eliminating radicals. To ensure a good effect on scavenging radicals, it is better to prepare theabrownin at pH6.0 with concentration between 0.08 and 0.1 mg/ml for drinking. [Conclusion] Results of this study provide a basis for developing functional products of theabrownin from Pu-erh tea in the future.

Analysis of Monosaccharide Composition of Pu-erh Tea Polysaccaride by Pre-column Derivatization HPLC

[Objective] This study aimed to establish a pre-column derivatization HPLC method for the identification and analysis of monosaccharide composition of Pu-erh tea polysaccharide. [Method] Pu-erh tea polysaccharide was extracted using the wa- ter extraction method, further isolated and purified by DEAE cellulose-52 columns. The obtained tea polysaccharide and four components TPS1, TPS2, TPS3 and TPS, were first derived by 1-phenyl-3-methyl-5-pyrazolone （PMP）, and then the PMP derivatives of monosaccharide were analyzed by high performance liquid chromatog- raphy （HPLC）. [Result] Pu-erh tea polysaccharide contained eight kinds of monosac- chaddes （mannose, rhamnose, glucuronic acid, galacturonic acid, grucose, galactose, arabinose, fucose）, without xylose; so it was the same with TPS1; each of TPS2, TPS3 and TPS4 contained seven monosaccharides, while no fucose. [Conclusion] This method is simplified and rapid, which can be used to determine the monosac- charide composition of Pu-erh tea polysaccharide and monosaccharide content.

Characterization of aroma compounds of Pu-erh ripen tea using solvent assisted flavor evaporation coupled with gas chromatography-mass spectrometry and gas chromatography-olfactometry

Pu-erh ripen tea becomes popular worldwide owing to its unique taste and aroma.In the present study,volatile compounds from Pu-erh ripen tea were extracted using a solvent assisted flavor evaporation(SAFE)and analyzed with a gas chromatography-mass spectrometry(GC-MS)and a gas chromatography olfactometry(GC-O).Results demonstrated that 58 major volatile compounds and 24 aroma active substances of Pu-erh ripen tea were identified by GC-MS and GC-O analysis.Among volatile compounds identified,methoxyphenyl compounds were considered as the dominate compounds in the aroma of Pu-erh ripen tea.Further investigation showed that 6 methoxybenzenes were responsible for the aging aroma in Pu-erh ripen tea;α-ionone,3,4-dimethoxytoluene,1,3-dimethoxybenzene,etc.were responsible for the wood-like aroma.Linalool,α-terpineol,α-ionone,β-ionone,and benzeneacetaldehyde were responsible for the floral odor.Compared the odor detection threshold(ODT)among the 8 methoxyphenyl compounds in water,1,2,3-trimethoxybenzene showed the highest ODT,followed by 3,4-dimethoxyphenol.1,3-dimethoxybenzene(105μg/L)and 1,2,3-trimethoxy-5-methylbenzene(100μg/L)were present at relatively low odor threshold values.The result indicated that methoxyphenyl compounds play a vital role in the unique flavor of Pu-erh ripen tea.

Reducing oxidative stress and hepatoprotective effect of water extracts from Pu-erh tea on rats with high-fat diet

Reducing oxidative stress and hepatoprotective effect of Pu-erh tea water extracts on rats fed with high-fat diet were researched for explaining health care of Pu-erh tea.Fifty SD rats were divided into five groups.The body weight was measured once a day.The malondialdehyde(MDA)and glucose(Glu)levels and the activities of alanine aminotransferase(ALT),aspartate aminotransferase(AST),nitric oxide synthase(NOS),and pyruvate kinase(PK)in serum were determined.Furthermore,the hepatic glycogen level(HGL)and the activities of hepatic total superoxide dismutase(T-SOD),catalase(CAT),and glutathione peroxidase(GSH-Px)were also measured after continuous administration for 12 weeks.The result demonstrated that Pu-erh extract caused the decreases in body weight,fat index,MDA and NOS levels,and the increases in hepatic T-SOD,CAT and GSH-Px activities,indicating that the extract may be due to inhibiting the increases of body weight and fat index,reducing oxidant stress state and inhibiting lipid peroxidation,thus decreasing the activities of ALT and AST,and protecting the liver in rat.Meanwhile,the extracts could increase the production of hepatic glycogen and the activity of PK,and reduce glucose level,protecting the liver from the diseases associated with type II diabetes.

Detection of composition of functional component theabrownins in Pu-erh tea by degradation method

Habitual tea consumption can reduce the risk of ASCVD morbidity and mortality and all-cause mortality in China,and long-term adherence to this habit can provide greater protection.Pu-erh tea is one of the representatives of post-fermented teas,and the polymers in Pu-erh tea have anti-cancer and anti-hyperlipidemic activities,but their chemical composition is still unknown.In this study,the chemical composition of Pu-erh tea was investigated in detail and eight(1–8)known compounds were isolated.The polymers in Pu-erh tea were also degraded by thiol degradation,and the fragments of quercetin and(–)-epicatechin-3-O-gallate were found in the thiol degradation products of Pu-erh tea polymers by UPLC observation and separation and purification.This is the first time that this fragment was obtained in Pu-erh tea polymer.

Inhibitory Effects of Pu-erh Tea Leaves on Mouse Type IV Allergy

Pu-erh tea is one of post fermented tea manufactured through oxidative maturing by microorganisms. We investigated the preventive effects of pu-erh tea extract on oxazolone-induced type IV allergy in male (ICR) mice. Oral administration of 50 mg/kg water extract of pu-erh tea leaves resulted in significant preventive effects against mouse type IV allergy. The hydrophilic Theabrownin-like fraction (TBW-ND), with a high molecular weight of approximately 12,000 or higher, was prepared from pu-erh tea leaves by a solvent-extraction method, followed by Diaion HP-20 column chro-matography and dialysis. Oral and percutaneous administrations of TBW-ND at doses of 18.7 mg/kg and 0.037 mg/ear also resulted in significant preventive effects, which included preventing increases in levels of the proinflam-matory cytokine interleukin-12. The anti-allergic ingredients in TBW-ND were predicted to be highly complex compounds containing of polyphenols, polysaccharides and/or proteins. The results suggest pu-erh tea leaves could be a beneficial food for protecting against delayed-type allergy.

Anti-Obesity, Anti-Atherosclerotic and Anti-Oxidant Effects of Pu-Erh Tea on a High Fat Diet-Induced Obese Rat Model

Pu-erh tea, a traditional Chinese beverage, has been believed to have many benefits to human health and without side effects. In this study, we systematically analyzed the main active components of Pu-erh tea and investigated its anti-obesity, anti-atherosclerotic and anti-oxidant effects using an obese rat model. Obesity was induced by feeding a high-fat diet and subsequently the experimental obese mice were fed with high-fat diet supplemented with low (2.5%), medium (5%) or high (7.5%) doses of Pu-erh tea powder for 6 weeks respectively. As result, the body weight gain of the rats was decreased by medium and high doses of Pu-erh tea treatments. Furthermore, the levels of serum total cholesterol (TC), triglyceride (TG) and atherosclerosis index (AI) were significantly lowered by Pu-erh tea compared to the control group. Conversely, high density lipoproteincholesterol (HDL-C) level of the rats was significantly elevated by Pu-erh tea treatments. In addition, Pu-erh tea treatments increased the activities of anti-oxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxides (GSH-Px), whereas reduced the level of lipid peroxidation product malondialdehyde (MDA) in obese rats. Collectively, our find-ings revealed that Pu-erh tea exerts comprehensive benefits in anti-obesity, anti-atherosclerotic and anti-oxidant effects, therefore can be used as a promising functional food in obesity management.

Pu-erh tea: A review of a healthful brew

Pu-erh tea has been used for thousands of years to treat metabolic diseases.Recognized in Shen Nong's Herbal Classic,a compendium kept by the first traditional Chinese practitioners,it is still highly valued for its hypocholesterolemic and hypolipidemic effects.This review reports the processing and bioactive components of pu-erh tea.Recent human and animal studies of pu-erh tea and its potential therapeutic mechanisms have also been summarized.The interaction of liver and gut microbiome regulates the puerh tea biotransformation and endogenous metabolism,and thus contributes to the health benefits.

浸提工艺对普洱熟茶膏香气成分组成的影响

本研究采用响应面分析法(RMA)分析了不同浸提工艺参数进行浸提所制备的普洱熟茶膏的香气感官差异,并应用顶空固相微萃取技术提取普洱熟茶膏香气成分。实验结果表明,浸提温度和茶水比对香气成分有显著影响。在85℃浸提温度、12.5 min浸提时间、1∶12茶水比的条件下,浸提得到的普洱熟茶膏香气品质最佳,香气成分为雪松醇以及其他多种具有特殊香气的成分。

Development of the fingerprints of crude Pu-erh tea and ripened Pu-erh tea by high-performance liquid chromatography

A simple and accurate high-performance liquid chromatography（HPLC）method to generate the fingerprints of crude Pu-erh tea（CPT）and ripened Pu-erh tea（RPT）is described.A suitable chromatographic system was established using a linear gradient elution with acetonitrile and water containing 0.6% formic acid as the mobile phase and a detection wavelength of 300 nm.HPLC analysis identified 24 common peaks among RPT and 21 common peaks among CPT.This study revealed that crude Pu-erh tea and ripened Pu-erh tea contained some similar major constituents,but with distinctive peaks,which may be caused by the difference in the fermentation process.This HPLC fingerprint method could be used to evaluate and authenticate crude Pu-erh tea and ripened Pu-erh tea.

Influence of the post-fermentation by four Aspergillus strains on the aroma of pu-erh tea

Aroma is one of the most important factors for the flavor, taste, and quality of pu-erh tea, and the post-fermentation process has an important influence on the aroma of pu-erh tea. In the present study, the influence of fungi fermentation on the flavor of pu-erh tea was investigated and compared. Volatile compounds from pu-erh tea fermented by four Aspergillus strains, including A. niger, A. oryzae, /1. awamori, and A. glaueus, were extracted and analyzed using ultrasound-assisted extraction-dispersive liquid-liquid microextraction-gas chromatography-mass spectrometry （UAE-DLLME-GC-MS）, and a total of 63 volatile compounds were identified. In comparison with the sun-dried green tea, fermented pu-erh tea contained high levels of methoxyphenolic compounds, such as 1,2,3-trimethoxybenzene, which was the most abundant one. Our results confirmed that the characteristic methoxyphenolic compounds were produced by the activity of Aspergillus during the post-fermentation process, and A. niger and A. awamori were the most important strains for the formation of aroma quality of pu-erh tea.

茶香风味鱼脯的研制

以草鱼鱼糜为原料,绿茶茶粉为辅料,开发茶香风味鱼脯。采用正交试验设计,考察改良剂对鱼糜品质的影响并确定最佳风味配方,通过感官评定确定的最佳风味配方为:草鱼鱼糜100.0 g,食盐2.0 g,蔗糖8.0 g,生姜粉为2.0 g,味精1.0 g,绿茶茶粉(120目)2.0 g,大豆脱脂脱腥蛋白粉4.0 g,小麦蛋白粉2.0 g,酸变性淀粉8.0 g。

苦荞糊和苦荞茶挥发性香气成分分析

采用固相微萃取法(SPME)对苦荞茶和苦荞糊中的挥发性香气成分进行提取,并经气相色谱-质谱联用(GC-MS)技术定性分析。从苦荞茶和苦荞糊中分别检测出30种和41种挥发性香气成分,相同成分有15种,其中含量较高的是烃类、醛类和杂环类,三者在苦荞茶和苦荞糊中含量分别为24.56%、35.04%、18.42%和46.97%、21.22%、7.22%。研究表明,顶空固相微萃取具有快速简便、不使用溶剂和样品检测非破坏性等优点,结合气-质联用技术可以很好的分析苦荞产品中挥发性物质,并说明不同加工工艺制得的苦荞产品其挥发性物质存在一定差异。

不同加工工艺对红茶茶膏品质的影响

通过常规浸提、酶处理浸提两种提取工艺与真空减压浓缩、水浴浓缩两种干燥工艺制备红茶茶膏,并对其理化成分、色差及感官品质进行分析。结果表明,经酶处理后利用真空减压浓缩工艺能够显著提高红茶茶膏总糖、茶红素(TR)、茶黄素(TF)、茶褐素(TB)、儿茶素等理化活性成分含量,并提高红茶茶膏感官品质。色差分析b/a值和色相角(Hab)在红茶茶膏汤色分析中能更好反映红茶茶膏汤色状况,其与感官评分相关系数较高,可作为色差分析中衡量红茶茶膏色差品质的指标之一。

浆茶杀青工艺及贮藏保鲜研究

本试验对浆茶杀青工艺及贮放保鲜进行了研究。结果表明 ,投叶量 10 0g ,微波功率 110 0w ,微波杀青 16 0s ,可有效钝化酶活性 ,并有较好的保绿效果 ;在pH 7 5,Vit.C 0 45mg/g贮放条件下利于浆茶保绿 ;添加柠檬酸可明显提高茶多酚儿茶素及叶绿素在贮放中的残留量 。

3类茶叶粉对小麦面粉糊化特性的影响

研究绿茶粉、红茶粉、黑茶粉对3个筋力面粉(SF、MF、WF)糊化特性的影响,为茶叶粉在食品开发和加工中的应用提供依据。以强筋小麦‘西农364’、中筋小麦‘西农538’、弱筋品系‘522-1’作为供试材料,把3类茶叶粉以0%、2%、4%、6%、8%、10%的质量分数添加到3个筋力的面粉里,利用快速黏度仪(RVA)测定面粉糊化特性。结果表明:强筋面粉(SF)的峰值黏度、回生值低于中筋面粉(MF)和弱筋面粉(WF)。强筋面粉(SF)崩解值最小,弱筋面粉(WF)崩解值最大;3类茶叶粉对低筋面粉的热稳定、抗剪切力和耐搅拌力增强最明显,其次是中筋面粉和强筋面粉;随着3类茶叶粉添加量的增大,3个筋力面粉冷糊的稳定性逐渐增强,冷糊老化速度逐渐减弱;峰值时间随着茶叶粉添加量的增加呈现降低趋势;峰值温度受茶叶粉影响很小。绿茶粉、红茶粉、黑茶粉对3个筋力面粉黏度特性均产生不同程度的影响,给不同筋力的面粉里添加适量的不同种类茶叶粉可不同程度地提高或改善面粉的质量和品质。

天然抗氧化剂对芝麻酱储存稳定性的影响

在芝麻酱中分别添加茶多酚和迷迭香提取物,置于(50±1)℃恒温烘箱内储存至60 d,期间取样萃取其中的油脂并测定其过氧化值和氧化诱导时间,研究天然抗氧化剂对芝麻酱储存稳定性的影响。结果表明:添加茶多酚和迷迭香提取物对提升芝麻酱的储存稳定性是有效的;在延长芝麻酱中油脂的氧化诱导时间方面,添加迷迭香提取物比茶多酚效果好,且随着迷迭香提取物添加量的增加,氧化诱导时间延长;在过氧化值升高及芝麻酱综合感官品质方面,添加茶多酚比迷迭香提取物效果好。茶多酚在添加量达到0.4 g/kg时可将芝麻酱的氧化诱导时间从12.9 h提高至16.8 h,提高了3.9 h,迷迭香提取物添加量达到0.70 g/kg时,可将芝麻酱的氧化诱导时间从12.9 h提高至31.6 h,提高了18.7 h。综合芝麻酱过氧化值、氧化诱导时间及综合感官品质的结果,本着在达到预期效果的前提下尽可能降低抗氧化剂使用量的原则,茶多酚的最适添加量为0.26 g/kg,迷迭香提取物的最适添加量为0.40 g/kg。