Research on the Extraction Process of Pu-erh Tea Polysaccharide by Response Surface Analysis

[Objective] This study aimed to optimize the extraction process parameters of Pu-erh tea polysaccharide. [Method] Single-factor experiment was carried out to analyze the influences of three main factors, including extraction temperature, ex- traction duration and solid-liquid ratio, on the extraction yield of tea polysaccharide. Box-Behnken central composite design and response surface methodology were adopted to determine the optimal extraction process of Pu-erh tea polysaccharide. [Result] The results of response surface analysis showed that the optimal extraction process was solid-liquid ratio of 1：17, extraction temperature of 80 ℃ and extraction duration of 78.5 min, and the Pu-erh tea polysaccharide yield was 12.72%. [Conclu- sion] Using response surface methodology （RSM） is feasible for the optimization of Pu-erh tea polysaccharide extraction process, and the tea polysaccharide yield increased significantly.

Structure variety and its effects on biological activity of tea polysaccharides

Tea polysaccharides(TPSs),one of the major bioactive ingredients in tea,have been widely studied due to their variety of biological activities,including antioxidant,cancer prevention,hypoglycemia,anti-fatigue,anti-coagulant,anti-obesity and immunomodulatory effect.The biological effectiveness of TPSs has direct relation with their structures such as monosaccharide composition,molecular weight,glycosidic linkages,conformation and others,which can be influenced by tea materials,processing methods,extraction and purification procedures among others.Comparing to the study of tea polyphenols,the exploration of TPSs in structural elucidation and biofunctionality is very preliminary.Yet several factors affecting the structural change of TPSs have been studied and identified.Consequently,the variation of some TPS biological activity brought by the change of TPS structures has been evaluated and preliminary correlation of structure activity relationship of TPSs has been performed.Therefore,this review aims to serve as a summary research report regarding the influencing factors on TPSs structures and consequential effects on the biological activities of TPSs.We hope to provide updated information and systematic references for future study and functional food development of TPSs.

Fermentation characteristics and probiotic activity of a purified fraction of polysaccharides from Fuzhuan brick tea

Polysaccharides from Fuzhuan brick tea(FBTPS),one of most important bioactive components in tea,showed various health-promoting functions.Our previous work demonstrated that the crude FBTPS(CFBTPS)could modulate the gut microbiota.However,which purified fraction in CFBTPS contributing to the modulation of gut microbiota remains unclear.Thus,the fermentation characteristics and probiotic activity of a purified fraction(FBTPS-2-1)of CFBTPS were evaluated in this work.The results showed that gut microbiota could utilize FBTPS-2-1 to produce short-chain fatty acids including acetic,propionic,n-butyric and n-valeric acids.FBTPS-2-1 could modulate the structure and metabolic pathways of gut microbiota.FBTPS-2-1 could increase the health-promoting gut microbiota such as Prevotellaceae and Bifidobacteriaceae,and decreased the harmful bacteria such as Enterobacteriaceae and Fusobacteriaceae.The results of metagenomics showed that Prevotella copri and Megamonas funiformis were the dominant bacteria after fermentation of FBTPS-2-1.Furthermore,FBTPS-2-1 could regulate the biosynthesis and metabolism pathways of gut microbiota.Thus,the enrichment of food with FBTPS-2-1 is expected as a potential strategy for promoting human health due to modulation of gut microbiota.

Optimization of Extraction Process of Yingshan Cloud Tea Polysaccharides by Response Surface Methodology

[Objectives] This study was conducted to explore the optimal process conditions for hot water extraction of polysaccharides from Yingshan cloud tea. [Methods] Based on single factor experiments, with the extraction rate of polysaccharides as the response value and liquid-to-solid ratio, extraction temperature and extraction time as investigation factors, the optimum extraction process for tea polysaccharides from Yingshan cloud tea was determined by Box-Behnken central componse design and response surface analysis method. [Results] Under the conditions of the liquid-to-solid ratio of 50∶1(ml/g), the extraction temperature at 94 ℃ and the extraction time of 210 min, the extraction rate of polysaccharides from Yingshan cloud tea reached 2.16%. [Conclusions] This study will provide theoretical basis and reference for subsequent related research.

Optimization of Supercritical Fluid Extraction of Tea Flower Polysaccharides by Using Response Surface Method

Polysaccharide production from tea flower(TFPS) was carried out using supercritical fluid extraction(SFE).Response surface methodology(RSM),based on a five level,four variable small central composite design,was employed to obtain the best possible combination of extraction time,pressure,temperature and ethanol content of modifier for maximum production.The optimum conditions were as follows:extraction time of 170 min,pressure of45 MPa,temperature of 75 ℃,and 50% aqueous ethanol solution as modifier.Under these conditions,the experimental yield was 6.56 ± 0.37%,which was similar to the value predicted by the model.Monosaccharide composition of TFPS was fucose,rhamnose,arabinose,xylose,galactose,glucose,mannose,fructose,ribose,galacturonic acid and glucuronic acid in a molar percent of 31.69,0.21,0.49,1.29,35.82,0.97,1.63,18.34,7.88,1.06 and 0.63.Compared to other extraction methods,SFE could achieve higher yield and gain more types of monosaccharide.

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.

Green tea polysaccharide conjugates and gelatin enhanced viability of L. acidophilus by layer-by-layer encapsulation

Adverse environments such as the gastrointestinal tract can affect the efficacy of probiotics.Therefore,the adequate protection of probiotics and their total effect exertion are probiotics application research hotspots.Green tea polysaccharide conjugate(gTPC),an anionic polymer,and gelatin as the encapsulation materials,and layer-by-layer self-assembly technology as the method,were applied to encapsulate Lactobacillus acidophilus.Microscopic results showed that with the increase in the number of deposited layers,the encapsulation was more complete.After continuous exposure to simulated gastrointestinal fluid for 120 min,the survival rate of unencapsulated cells was 53.26%,and encapsulated cells with different deposited layers were 66.00%,71.99%,76.94%,and 79.89%,respectively.In addition,Gel/gTPC bilayers can efficiently improve cell thermotolerance and freezing resistance.Results indicated that the more the number of Gel/gTPC bilayers,the more significant the protection is.Therefore,gTPC and Gel are viable materials to protect probiotics through microencapsulation by Layer-by-layer self-assembly.

武夷岩茶酸性茶多糖对2型糖尿病大鼠胆汁酸的调节作用机制

[目的]研究从武夷岩茶黄片中提取的一种酸性茶多糖对高血糖大鼠胆汁酸的影响。[方法]通过体外试验评价茶多糖对胆酸盐的结合能力;通过液质联用仪测定大鼠盲肠内容物中胆汁酸组成,并检测大鼠肝脏、胰腺的胆汁酸受体法尼醇X受体FXR、G蛋白偶联胆汁酸受体TGR5 mRNA的相对表达量;Western Blot法检测结肠组织胰高血糖素样肽-1的表达水平。[结果]茶多糖对结合型和游离型的胆酸盐均有一定的结合能力,并且对结合型胆酸盐具有更好的结合能力,当茶多糖质量浓度为2.00 mg/mL时,其对胆酸钠的结合率仅为同浓度下甘氨胆酸钠和牛磺胆酸钠结合率的57.59%,62.62%。茶多糖的干预对大鼠盲肠内容物中胆汁酸水平的影响主要表现为初级胆汁酸鹅去氧胆酸水平的增加,以及次级胆汁酸脱氧胆酸、石胆酸水平的降低。此外,其对大鼠肝脏、胰腺胆汁酸受体FXR、TGR5的mRNA表达具有上调作用;对胰高血糖素样肽-1表达水平无显著性影响。[结论]茶多糖干预可改变大鼠初级胆汁酸/次级胆汁酸的比率,而疏水性更高的次级胆汁酸在肠肝循环中吸收性更差。

响应面法优化乌龙茶提取茶多糖的工艺研究

以乌龙茶为原料,选用回流法提取茶多糖,根据Plackett-Burman实验设计考察提取温度、提取时间、提取次数、料液比等多种因素对茶多糖提取率的影响;在单因素实验基础上,运用Box-Behnken实验设计进行响应面剖析.实验结果显示,当提取温度100℃、提取时长80 min、料液比1∶50时,乌龙茶茶多糖的提取率显著增加,得率是6.13%.对最佳提取工艺开展验证,结果显示实测均值与模型估计值相近,表明该提取工艺平稳可行.

茶成分对肠道菌群的调控作用及其健康效应的研究进展

茶是世界上最受欢迎的健康饮料之一,富含茶多酚、茶多糖、茶色素和茶皂素等多种生物活性成分,对人体健康具有重要影响。肠道是一个复杂而稳定的生态系统,肠道微生态与人体健康密切相关。肠道菌群是茶成分发挥生理调节作用和健康效应的主要作用靶点,本文对近年来几种重要茶成分对肠道菌群的调节作用及其对机体健康的影响相关研究进展进行了综述。茶成分主要通过靶向肠道菌群调节糖代谢和脂代谢,减轻炎症和肠道损伤,缓解情绪和记忆障碍以及调节昼夜节律,发挥其健康效应。阐明茶成分调控肠道菌群的内在作用机制将为更好地利用茶产品来改善肠道微生态,促进人体健康提供科学依据。