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.

Tea saponins affect in vitro fermentation and methanogenesis in faunated and defaunated rumen fluid

The effect of tea saponins (TS) on rumen fermentation and methane emission was examined using an in vitro gas production technique named Reading Pressure Technique. Three levels of TS addition (0, 0.2, 0.4 mg/ml) were evaluated in the faunated and defaunated rumen fluid. Compared to the control, TS addition decreased the 24 h gas production in the faunated rumen fluid, but had a minor effect on gas yield in the defaunated rumen fluid. The TS significantly reduced methane production in vitro. In the faunated rumen fluid, 0.2 or 0.4 mg/ml TS decreased the 24 h methane emission by 12.7% or 14.0%, respectively. Rumen fluid pH value was affected neither by TS addition nor by defaunation. The TS addition had only minor effects on volatile fatty acids, but the yield and pattern of volatile fatty acids were greatly affected by defaunation. While the molar proportion of acetate was not affected by defaunation, the propionate was significantly increased and the butyrate significantly decreased. Ammonia-N concentration and microbial protein yield were influenced by TS inclusion and defaunation. Inclusion of 0.4 mg/ml TS increased the microbial protein mass by 18.4% and 13.8% and decreased the ammonia-N concentration by 8.3% and 19.6% in the faunated and defaunated rumen fluid, respectively. Protozoa counts were significantly reduced by TS inclusion. The current study demonstrated the beneficial effect of TS on methane production and rumen fermentation, and indicated that this may be due to the effect of the associated depression on protozoa counts.

Comparative study on Leaf Tissue Morphologic Changes of Chang-Sheng-Chuan Green Brick Tea Before ad After Fermentation

[Objective] The aim was to understand the change of fermentation pro- cess of Chang-sheng-chuan green brick tea and analyze the changes in the con- tents of structure components of tea leaves before and after fermentation. [Method] Ten tea leaves before and after fermentation were chosen. The tea leaves sections were made using paraffin microtomy, PAS staining, and observed under light mi- croscopy. Through image analysis for the tea leaves, we compared the changes on the areas of the cellulose and colloid in cell before and after pile-fermentation. At the same time, the tea leaves were observed under transmission electron micro- scope. [Result] The results showed that the pile-fermentation process caused the tea leaves tissue to become loose, and expanded the cell space. Besides, the cell wall of tea leaves was obviously thinning, and even breaking which composed of cellulose. Image analysis showed that the leaf fiber composition reduced significant- ly, with a corresponding increase of yellow colloid in cell. Under observation of transmission electron microscope, there were large amounts of fungi located in the space between the colloid and the cell wall of the tea leaves after pile-fermentation. [Conclusion] The fermentation of Green brick tea is the process of microbial bio- transformation of tea, which is dominated by microbe and consumed the cellulose components of tea leaves.

Isolation and identification of Starmerella davenportii strain Do18 and its application in black tea beverage fermentation

The objective of this study was to isolate and identify a yeast strain from the kombucha beverage and evaluate its potential as a novel starter in beverage fermentation in vitro.Starmerella davenportii Do18 was characterized for its cholesterol reduction;growth at different conditions such as temperatures(25,30,37 and 42◦C),low pH(1.2,1.5,2.03.0,and 7.0),bile salts(0%,0.25%,0.5%,1%and 2%)high-sucrose stress(2%,10%,20%,40%and 60%);and in-vitro survival in gastric and intestinal environments.Results showed that the yeast strain has a cholesterol-lowering capacity of 45%±2%,grew at temperature of 37◦C and is resistant to pH 1.5,2%bile and 40%sucrose solution,could survive in simulated gastric and intestinal environments.The physicochemical characteristics of the fermented beverages were also evaluated,which indicated that the yeast has pH reduction capacity and can produce organic acids and volatile compound such as 2-phenylethanol.Furthermore,the fermented beverage also has high total phenolics and flavonoids content and showed great antioxidant and antimicrobial activities.Therefore,the findings of this research provide strong evidence that S.davenportii Do18 has good fermentation properties,can be a potential starter in food and beverage fermentation.

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.

Monitoring black tea fermentation quality by intelligent sensors: Comparison of image, e-nose and data fusion

To scientifically and objectively monitor the fermentation quality of black tea,a computer vision system(CVS)and electronic nose(e-nose)were employed to analyze the black tea image and odor eigenvalues of Yinghong No.9 black tea.First,the variation trends of tea polyphenols,volatile substances,image eigenvalues and odor eigenvalues with the extension of fermentation time were analyzed,and the fermentation process was categorized into three stages for classification.Second,principal component analysis(PCA)was employed on the image and odor eigenvalues obtained by CVS and e-nose.Partial least squares discriminant analysis(PLS-DA)was performed on 117 volatile components,and 51 differential volatiles were screened out based on variable importance in projection(VIP≥1)and one-way analysis of variance(P<0.05),including geraniol,linalool,nerolidol,and α-ionone.Then,image features and odor features are fused by using a data fusion strategy.Finally,the image,smell and fusion information were combined with random forest(RF),K-nearest neighbor(KNN)and support vector machine(SVM)to establish the classification models of different fermentation stages and to compare them.The results show that the feature-level fusion strategy integrating the SVM was the most efficient approach,with classification accuracy rates of 100%for the training sets and 95.6%for the testing sets.The performance of Support Vector Regression(SVR)prediction models for tea polyphenol content based on feature-level fusion data outperformed data-level models(Rc,RMSEC,Rp and RMSEP of 0.96,0.48 mg/g,0.94,0.6 mg/g).

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...

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.

Recent trends in Kombucha:Conventional and alternative fermentation in development of novel beverage

Kombucha is produced by fermenting sweetened tea with symbiotic culture of bacteria and yeast(SCOBY).Kombucha is slightly sweet and acidic tea beverage that is popular all over the world due to its refreshing taste and health-promoting active metabolites formed during the fermentation process.Sucrose-sweetened tea is the traditional substrate for kombucha fermentation.However,due to consumers’demand as well as availability of resources,various alternative substrates,such as honey,molasses and coffee,have been used in the production of kombucha over time to promote additional health benefits.Aside from that,kombucha fermentation supplementation,such as with herbs,bee pollen,and lactic acid bacteria,have also been used to develop new novel kombucha,to value-add the biological activities and sensory properties.The activity of Komagataeibacter spp.bacteria results in the formation of a polymeric cellulose pellicle during the kombucha fermentation process.The cellulose produced has a wide range of application in a variety of fields.In this review,conventional and alternative fermentation methods were reviewed to better understand the development of kombucha.

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.

干燥工艺对红薯叶冠突散囊菌发酵茶品质的影响

为探讨干燥工艺对红薯叶冠突散囊菌发酵茶品质的影响,探寻红薯叶冠突散囊菌发酵茶最适干燥工艺。采用不同温度(60、70、80℃)热风干燥(hot air drying, HAD)、60℃热泵干燥(heat pump drying, HPD)、真空冷冻干燥(vacuum freeze drying, FD)5种不同的干燥工艺对红薯叶冠突散囊菌发酵茶进行脱水处理,并对干茶样品进行感官评价同时检测分析了干茶中的主要成分及风味物质。结果表明,在HAD中,随着干燥温度的升高,茶叶总酚、总黄酮含量下降,可溶糖含量升高,单宁含量没有变化;HAD 80℃干茶中,引发茶汤涩味的酚类物质和黄酮含量低,茶汤色及香气感官评分高,香气组分最多且综合品质最好;HAD 60℃干茶总酚、总黄酮和苦味氨基酸含量均高,苦涩味较重;FD干茶外形评价最好且单宁含量最低,但其总酚和总黄酮最高,且青草香气重,这与其挥发性物质中愈创木酚含量高有关,使其感官评分较低。所有干茶样品的香气成分中,1-辛烯-3-醇、愈创木酚和β-紫罗兰酮的OAV值均高于100,是红薯叶冠突散囊菌发酵茶干茶中的关键香气成分。该研究为红薯叶冠突散囊菌发酵茶风味的形成及加工工艺优化提供了指导。

德昂酸茶乳酸菌发酵饮料的工艺优化及品质分析

该研究以德昂酸茶为原料,以植物乳杆菌和嗜酸乳杆菌为发酵菌种制备德昂酸茶乳酸菌发酵饮料,利用单因素试验和Box-Behnken试验设计优化发酵工艺条件,并检测其理化指标和微生物指标。结果表明,德昂酸茶乳酸菌发酵饮料最佳发酵工艺条件为白砂糖添加量4%、植物乳杆菌和嗜酸乳杆菌接种菌液体积比1∶2、菌种接种量2.5%、37℃发酵12 h。在此优化发酵工艺条件下,德昂酸茶乳酸菌发酵饮料的感官评分为84.85分,pH值为4.01±0.01,总酸含量为(0.34±0.02)g/L,可溶性固形物含量为(4.00±0.01)%,总糖含量为(2.24±0.1)g/100 mL,茶多酚含量为(13.73±0.29)g/L,游离氨基酸含量为(36.30±0.13)mg/100 mL,微生物指标均符合国家标准GB 7101—2022《食品安全国家标准饮料》的要求。