Puer Tea Research Articles

Identification and sorting of impurities in tea using spectral vision

Removing impurities from Puer tea is an important step in its processing. However, existing methods are unable to accurately and efficiently sort impurities from Puer tea. This study proposes a novel method based on spectral imaging technology to identify impurities in Puer tea. Hyperspectral images of tea and impurities were acquired in the 400–1000 nm wavelengths. The spectra of each category of samples were extracted from the hyperspectral images and comprehensively analysed and processed, mainly including outlier detection and elimination, spectral preprocessing, and characteristic wavelengths selection. Support vector machine (SVM) models are built based on full-spectrum data and characteristic wavelengths data to achieve pixel-level classification of hyperspectral images. The results showed that the best model based on full spectra achieved an accuracy of 97.8% on the test dataset. The best models based on characteristic wavelengths selected by successive projections algorithm and genetic algorithm achieved accuracies of 95.9% and 94.9%, respectively. Finally, these pixel classification models were applied to the test samples to test the effectiveness of the models in identifying impurities. The results indicate that the three selected models can effectively identify impurities and even perform well on identifying unfamiliar categories of impurities.

보이차 문화사에 있어서 『보이차기』의 위상에 대한 검토

This paper critically re-evaluates the status and significance of Puerchagi , a pivotal resource in the study of Pu’er tea culture during the Qing Dynasty. In this research, its contribution to the understanding of Pu’er tea culture is redefined by verifying the historical accuracy and cultural authenticity of Puerchagi through a comprehensive analytical approach. The study delves into the geographical origin, production method, and socioeconomic impact of Pu’er tea, in addition to an examination of the narrative style and methodology of Puerchagi. This research uncovers the historical context of Pu’er tea and enhances the understanding of its cultural heritage. The result is as follows. First, Puerchagi followed the compilation order, method, and most of the cited sources of Jeonhaewoohyeongji. Second, the description of Puer tea tribute represents the author's unique contribution. Third, most of the literature and materials related to Puer tea up to the early days of Daoguang were compiled through Puerchagi. Furthermore, since then, Puerchagi has become a model in Puer tea cultural history and has exerted a lasting influence.

코로나19 엔데믹 시대 차에 대한 소비자의 인식과 평가

This thesis analyzed consumers' perceptions and evaluations of tea in the COVID-19 endemic era using social big data from Sometrend. The purpose of this study was to provide basic data for the development of the tea industry. For this purpose, we selected eight teas (green tea, black tea, puer tea, kombucha, barley tea, pea tea, citron tea, and ginger tea) with more than 30,000 social media posts from consumers from July 13, 2022 to July 12, 2023 from social big data. Next, we collected and analyzed 30 relevant words of consumer perception of each tea and 30 emotional words of consumer evaluation of each tea through social big data. The main results are as follows. First, the associative words consumers mentioned with each tea in their social media posts were categorized into well-being, situation, and food. Second, the sentiment words consumers used to rate each tea in their social media posts were categorized into positive, neutral, and negative. In conclusion, for consumers during the COVID-19 endemic era, tea has been emphasized for its functionality to promote physical health, its healing properties for psychological stability, and its palatability for good taste.

Metabolite of chiral cycloxaprid in solvent and in the raw of Puer tea.

Cycloxaprid (CYC) with a chiral oxabridged cis- structure contains a pair of enantiomers. Enantioselective degradation, transformation and metabolite of CYC was performed in different solvents under light and raw Puer tea processing. The results showed that cycloxaprid enantiomers in acetonitrile and acetone was stable over 17day, however the transformation of 1S, 2R-(-)-cycloxaprid or 1R, 2S-(-)-cycloxaprid was founded in methanol. The fastest degradation of cycloxaprid occurred in acetone under light, the metabolites were founded with retention times (TR) at 34.83, 15.78min, which mainly was via the reduce reaction of NO2 to NO, and rearrange reaction to tetrahydropyran. Degradation pathways were via the cleavage of the oxabridge seven member ring and the whole C ring. However, the degradation pathway under raw Puer tea processing was via the cleavage of whole C ring and the cleavage of oxabridge seven member ring and reducing NO2, then it underwent an elimination of nitromethylene and rearrange reaction. This pathway of Puer tea processing was firstly founded.

Research on the Efficacy of Ganpu Vine Tea in Inhibiting Uric Acid Production.

Ganpu vine tea is a new type of health care citrus fruit tea made from citrus shell, Pu-er tea, and vine tea baked as raw materials. In this study, the in vitro uric acid synthase inhibition system and hyperuric acid cell model were constructed to appraise the uric acid lowering efficacy of Ganpu vine tea, traditional Ganpu tea, and vine tea. Results showed that in the uric acid synthase inhibition system, the aqueous extract can inhibite the puric metabolically related enzymes, such as adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), and xanthine oxidase (XOD). The ability of the aqueous extract to inhibit the above enzyme was as follows: vine tea > Ganpu vine tea > Ganpu tea; all teas had a strong effect on XOD inhibition. The hyperuric acid cell model test showed that the aqueous extract inhibited uric acid production through accumulating inosine and hypoxanthine and hindering xanthine synthesis. The uric acid reductive ability was as follows: Vine tea > Ganpu vine tea > Ganpu tea. The inhibition of enzymes related to uric acid synthesis and the inhibition of uric acid production were significantly enhanced through adding vine tea to Ganpu tea. It also shows that flavonoids are the main factor driving this ability because they are the main active ingredients in these botanical drinks.

Synthesis of molecularly imprinted polymer based on cooperative imprinting for enrichment of gallic acid in Puer tea

AbstractThe molecularly imprinted polymer (MIP) for gallic acid (GA) was prepared based on the cooperative imprinting of boronate affinity interactions and hydrogen bond. The fabricated MIP were designed by the polymerization of template with co‐functional monomer, 3‐acrylamidophenylboronic acid (AAPBA) and methacrylic acid (MAA). The characteristics of the resulting polymer (AAPBA‐co‐MAA MIP) were tested by scanning electron microscope (SEM), Fourier transform infrared spectra (FTIR) and nitrogen adsorption–desorption. Bonding performance demonstrated that the AAPBA‐co‐MAA MIP possessed the excellent recognition ability in the incubation solution with pH 7.4 and presented higher adsorption capacity, faster adsorption rate and satisfactory selectivity for GA. Additionally, the AAPBA‐co‐MAA MIP revealed the good applications in the separation and enrichment of GA from Puer tea, and the amount of GA enriched by them was determined to be 2.75 mg g−1. This work suggested that the integration of cooperative imprinting strategy between covalent and non‐covalent would be an effective way to improve the specific recognition performance of the MIP.

Enantioselectivity and residue analysis of cycloxaprid and its metabolite in the pile and fermentation processing of Puer tea by ultraperformance liquid chromatography-high-resolution mass spectrometry.

The residues of cycloxaprid enantiomers and metabolites are investigated by ultraperformance liquid chromatography–high‐resolution mass spectrometry (UPLC‐HRMS) during raw and ripen Puer tea processing. A Chiralpak AG column with chiral stationary phase of amylose tris (3‐chloro‐5‐methylphenylcarbamate) is succeed to separate the 1R, 2S‐cycloxaprid, 1S, 2R‐cycloxaprid, and their metabolite, which is identified as nitrylene‐imidazolidine. It is not conversed 1R, 2S ‐cycloxaprid into 1S,2R‐cycloxaprid during Puer tea processing. The estimated half‐lives of the 1R,2S‐cycloxaprid and 1S,2R‐cycloxaprid are 0.97 and 1.1 h, respectively, and 1R,2S‐cycloxaprid decreases more quickly than the 1S,2R‐cycloxaprid. During raw Puer tea processing, the half‐lives of 1R, 2S‐cycloxaprid and 1S, 2R‐cycloxaprid are 1.68 h and 1.77 h, but the residue is still detected even if it is over 730 day. However, the half‐lives of 1R,2S ‐cycloxaprid and 1S,2R‐cycloxaprid are 0.60 day and 0.63 day during ripen tea processing. The amounts of metabolite are more in raw tea than in ripen tea; the terminal residues are still detected until 730 days during raw tea. A significant enantioselectivity of 1R, 2S‐cycloxaprid and 1S, 2R‐cycloxaprid is observed during raw tea or ripen tea processing. The degration result shows the enantioselectivity of cycloxaprid in raw or ripen Puer tea processing.

Phytochemical profile of differently processed tea: A review.

Fresh tea leaves (Camellia sinensis (L.) O. Kuntze) are processed by various techniques to produce different types of tea. The most common way to classify tea types is based on the similarities in processing methods resulting in the five commonly recognized tea types: white, green, oolong, black, and pu-erh teas. The differences in the degree and nature of fermentation of tea leaves lead to different chemical changes depending on the processing method. Understanding the phytochemical profile of differently processed tea is important, as tea types classified by processing methods are currently not well defined because the chemical parameters for these tea types are still not established. Therefore, any significant characteristics found for a tea type due to processing may be helpful in defining tea types. However, the evidence on the impact of tea processing on phytochemical profile and contents in differently processed tea is currently unclear. Therefore, this review aims to examine (1) the processing techniques of white, green, oolong, black, and pu-erh tea, (2) the impact of tea processing on tea phytochemicals, and (3) the key characteristics associated with the phytochemical profiles of differently processed tea. PRACTICAL APPLICATION: Tea (Camellia sinensis (L.) O. Kuntz) is the most widely consumed beverage in the world. Tea consumption has been demonstrated through in-vitro experiments and in animal and human intervention studies to exhibit potential in preventing various oxidative stress-related chronic diseases, such as cardiovascular diseases, Alzheimer.s disease, diabetes and certain cancers. Based on the processing methods, tea is commonly categorized into white, green, oolong, black and pu-er tea. However, there are large overlap in processing methods between some teas and, more importantly, the chemical compositions of differently processed teas are highly variable. This review aims to examine (1) how white, green, oolong, black and Pu-erh tea are processed, (2) what are the effects of tea processing on tea phytochemicals and (3) to identify whether there are key characteristics associated to the phytochemical profiles of differently processed teas. The review will contribute to tea research in collating in one article the state of knowledge on the chemical changes and composition of the differently processed teas, and point to future direction in this area of research.

Nonstereoselective dissipation of sulfoxaflor in different Puer tea processing.

The stereoisomer behavior of sulfoxaflor was investigated by liquid chromatography‐tandem mass spectrometry (LC‐MS/MS) during raw Puer tea, ripen Puer tea, and sun‐dry Puer tea processing. The persistence of sulfoxaflor stereoisomers was consistently prolonged with different Puer tea processing from sun‐dry Puer tea, ripen Puer tea to raw Puer tea with t 1/2 4.0–4.2 hr (sun‐dry Puer tea) to 6.21–7.04 months (raw Puer tea). Three fermentation temperature in ripen Puer tea shown that the sulfoxaflor residue was easy to degrade under low fermentation temperature (37°C). It implied that enzyme catalysis may play an important role in degradation of sulfoxaflor. The no‐enantioselective dissipation of sulfoxaflor was found in different Puer tea processing.

Polyphenol, Flavonoid and Tannin Variation in Puer Tea Extracts

Polyphenol, Flavonoid and Tannin Variation in Puer Tea Extracts

중국 운남성(雲南省) 보이차 포장의 시각요소 분석 - 중국 보이차(普洱茶) 5대 브랜드 중심으로 -

중국은 차나무의 발원지로서 오래전부터 일상에서 차를 마시는 문화가 발달된 국가이다. 차문화의 역사 는 대략 4,700년 전부터 시작 되었다. 그 중에서 보 이차(普洱茶)는 중국을 대표하는 차라고 말할 수 있 다. 포장디자인의 문화가치는 물질적 문화와 정신적 문화만 단순히 나타내는 것이 아니라, 물질적 문화의 표현 양식을 토대로 정신적 문화를 결합시킨 것이다. 또한 보이차의 민족문화적 특징, 즉 운남성의 소수민 족의 문화를 소비자의 문화적 심리를 충분히 고려한 후에 독특한 특징을 가지는 가치적 소비 취향을 구 성했다. 보이차 문화적 가치는 지역문화를 토대로 사 회적 의미와 가치관을 부여한 것이다. 결국 중국 보 이차 포장디자인의 발전방법은 포장디자인에 민족문 화요소가 내포되어 있음을 각성하고, 보이차(普洱茶) 의 포장디자인은 중국의 문화를 이미지화하는 표현 방식 중 하나라고 판단하였다. 본 연구는 중국민족문화에 대한 문헌을 통하여 중 문화를 고찰하고, 중국 5대 보이차 제조회사의 포장디자인을 분석하여 중국 보이차 포장디자인에 운남성의 소수민족의 민족문화 특징이 활용되었는 지 살펴보고 발전방향을 제시한다. 연구범위는 중국 운남성에서 생산되는 보이차에 그 범위를 한정하고, 중국 5대 보이차 제조회사의 포장디자인으로 그 범 위를 제한한다. 결과로 보이차 포장디자인에 소수민 족의 문화적 특징이 적용되었음을 알 수 있었으며, 국제적 소비자로 확장되면서 운남성 보이차 포장디 자인에 민족문화적 이미지를 잘 도출하여 접목하는데 도움이 되기를 기대한다.

Tea Garden Detection from High-Resolution Imagery Using a Scene-Based Framework

Tea cultivation has a long history in China, and it is one of the pillar industries of the Chinese agricultural economy. It is therefore necessary to map tea gardens for their ongoing management. However, the previous studies have relied on fieldwork to achieve this task, which is time-consuming. In this paper, we propose a framework to map tea gardens using high-resolution remotely sensed imagery, including three scene-based methods: the bag-of-visual-words (BOVW) model, supervised latent Dirichlet allocation (sLDA), and the unsupervised convolutional neural network (UCNN). These methods can develop direct and holistic semantic representations for tea garden scenes composed of multiple sub-objects, thus they are more suitable than the traditional pixel-based or object-based methods, which focus on the local characteristics of pixels or objects. In the experiments undertaken in this study, the three different methods were tested on four datasets from Longyan (Oolong tea), Hangzhou (Longjing tea), and Puer (Puer tea). All the methods achieved a good performance, both quantitatively and visually, and the UCNN outperformed the other methods. Moreover, it was found that the addition of textural features improved the accuracy of the BOVW and sLDA models, but had no effect on the UCNN.

발효차를 통한 한국문화유전자 연구

This thesis concerns a study on characteristics of the fermented tea in the Korean cultural genes. THE KOREAN STUDIES INSTITUTE released the Korea s representative cultural gene, Society with a community and a natural and mature relationship is a good representation of the Korean sentiment. Korean tea culture was polite to gods and people in spirit, harmonization in social aspect, affection in emotional aspect, and fermentation in internal aspect, it showed a variety of relationships with cultural genes. In particular, because korean has long been drinking rice cake shaped tea, which is fermented by microorganisms, in the history of tea culture in Korea, this thesis studied the Korean cultural genes through the fermented tea by microorganisms. This fermented tea inhibits the activity of enzymes in tea leaves and actively uses microorganisms such as fungi, yeasts, and germs. Among them, the aerobic fermented tea, which is fermented by mold, is a tea made from the longer storage time of the microorganisms control method, and are Chungtaejeon and dark tea. In response, the researcher studied the connection with Korean cultural genes through fermentation of Puer tea and Cheongtaejeon, In particular, rice cake shaped tea had Korean cultural genes such as Etiquette, Society, Fermentation and Affection, which are representative of the cultural genes of Korea, and it was known that it is now being passed down to Korea. In addition, the researcher is preparing an experimental analysis to enhance the utilization value of the Korean fermented tea, which has great cultural value as a mental and cultural product in Korea. It is believed that this will be an important indicator in determining the brand of the fermented tea in Korea in the future.

Sensorial Place-Making in Ethnic Minority Areas: The Consumption of Forest Puer Tea in Contemporary China

This article examines sensorial place-making through analysing the taste and other sensory experiences of forest Puer tea in its consumption among the urban middle class in mainland China. In the process of creating the ‘terroir’ of forest Puer tea, sensorial experience has been frequently linked to its place of origin. I argue that ethnic minorities who cultivate the tea play a vital part in the imagination of the tea's terroir. Trips by consumers to the mountains where the tea is cultivated, which aim at facilitating a ‘full experience’ of the tea and its culture, have generated a special pattern of interactions between the urban middle class who consume the tea and the ethnic minorities who cultivate it. The consumption of Puer tea, which brings about social imaginary and transcendent economic value, has become a driving force for producing the locality of ethnic minority areas.

Sphingofungins G and H: new five-membered lactones from Aspergillus penicilliodes Speg.

Two new sphingofungins G (1) and H (2) with a five-membered lactone ring were identified from the solid-state fermentation of Aspergillus penicilliodes Speg., a dominant microorganism isolated previously from the post-fermentation of ripe Pu-er tea, together with six known metabolites. Their structures were elucidated by extensive spectroscopic methods. All of them were isolated from the mycelia culture of A. penicilliodes for the first time. The known compound, trypacidin, exhibited potent cytotoxities against five human cancer cell lines, e.g. myeloid leukemia HL-60, lung cancer A-549, hepatocellular carcinoma SMMC7721, breast cancer MCF-7, and colon cancer SW480, with IC50 values of 0.55, 11.45, 10.95, 3.58, and 3.49 μM, resp., while cisplatin as the positive control, with IC50 values of 8.63, 24.15, 21.99, 27.29, and 23.61 μM, resp.

Two New Indolyl Diketopiperazines, Trypostatins C and D from Aspergillus penicilliodes Speg.

Twelve indolyl diketopiperazines 1–12 were isolated from the mycelia culture of Aspergillus penicilliodes Speg., a dominant microorganism from the post fermentation process of ripe Pu-er tea. Their structures were elucidated by extensive spectroscopic methods. Among them, trypostatins C (1) and D (2) featuring with a rare methyl vinyl ketone side chain at C-2 are new compounds, while 3 and 4 were obtained for the first time from nature source. The isolates 3–12 did not show obvious cytotoxicities against five human cancer cell lines at a concentration of 40 μM.

Use of a Headspace Solid-Phase Microextraction-Based Methodology Followed by Gas Chromatography–Tandem Mass Spectrometry for Pesticide Multiresidue Determination in Teas

This study reports on the development of a fast and efficient method based on headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography–tandem mass spectrometry (GC–MS/MS) for simultaneous analysis of 128 volatile or semi-volatile pesticide residues belonging to nine classes of pesticides. The important factors related to HS-SPME performance were optimized; these factors include fiber types, water volume, ion strength, extraction temperature, and extraction time. The best extraction conditions include a PDMS/DVB fiber, and analytes were extracted at 90 °C for 60 min from 1 g of tea added to 5 mL of 0.2 g mL−1 NaCl solution. The methodology was validated using tea samples spiked with pesticides at three concentration levels (10, 50, and 100 μg kg−1). In green tea, oolong tea, black tea, and puer tea, 82.8, 88.3, 79.7, and 84.3% of the targeted pesticides meet recoveries ranging from 70 to 120% with a relative standard deviation of ≤ 20%, respectively, when spiked at a level of 10 μg kg−1. Limits of quantification in this method for most of the pesticides were 1 or 5 μg kg−1, which are far below their maximum residue limits prescribed by EU. The optimized method was employed to analyze 30 commercial samples obtained from local markets; 17 pesticide residues were detected at concentrations of 2–452 μg kg−1. Chlorpyrifos was the most detected pesticide in 80% of the samples, and the highest concentration of dicofol (452 μg kg−1) was found in a puer tea. This is the first time to find that the optimized extraction temperature for pesticide residues is 90 °C, which is much higher than other reported HS-SPME extraction conditions in tea samples. This developed method could be used to screen over one hundred volatile or semi-volatile pesticide residues which belong to multiple classes in tea samples, and it is an accurate and reliable technique.

Determination of Pesticide Residues in Teas via QuEChERS Combined with Dispersive Liquid–Liquid Microextraction Followed by Gas Chromatography–Tandem Mass Spectrometry

In this study, an effective gas chromatography–tandem mass spectrometry method was developed to determine 47 pesticide residues in tea. Sample preparation involved a quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure, wherein the sample is extracted by acetonitrile and cleaned up with multiwalled carbon nanotubes and primary secondary amine adsorbents; dispersive liquid–liquid microextraction (DLLME) was subsequently performed using carbon tetrachloride as extractive solvent and the extract obtained by QuEChERS as dispersive solvent. Factors influencing DLLME efficiency, including type and volume of extractive solvent, volume of dispersive solvent, and extraction time were evaluated. For validation purposes, recovery studies were performed using matrix blanks fortified with pesticides at three concentrations, namely, 10, 50, and 100 μg kg−1. Most of the analytes were recovered at an acceptable range of 70‒120% and RSDs ≤ 20% were acquired for green tea, oolong tea, black tea, and puer tea. Limits of quantification of pesticides obtained for these teas were sufficiently low, and most pesticides levels were lower than 10 μg kg−1, which satisfies the requirements for maximum residue levels (MRLs) as prescribed by the European Community. Twenty-four commercially available tea samples were analyzed using this optimized method. Results revealed that the contents of chlorpyrifos and alpha-HCH from different green tea samples exceed the MRLs, and chlorpyrifos, bifenthrin, lambda-cyhalothrin, and cypermethrin are among the most frequently detected pesticides in teas.

The anti-aging and anti-oxidation effects of tea water extract in Caenorhabditis elegans

Tea includes puer tea, black tea, green tea and many others. By using model organism Caenorhabditis elegans, the anti-aging and anti-oxidation effects of tea water extract were systemically examined in this study. We found that water extract of puer tea, black tea and green tea all increased the lifespan of worms, postponed Aβ-induced progressive paralysis in Alzheimer's disease transgenic worms, and improved the tolerance of worms to the oxidative stress induced by heavy metal Cr6+. Moreover, the anti-oxidation effects of tea water extract at low concentration were different among 4 kinds of brands of green tea. The underlying mechanisms were further explored using genetically manipulated-mutant worms. The anti-oxidative stress effects of green tea water extract depend on the dietary restriction and germline signaling pathways, but not the FOXO and mitochondrial respiratory chain signals. Therefore, tea water extract provides benefits of anti-aging, anti-AD and anti-oxidation.

Aflatoxin B1 can be complexed with oxidised tea polyphenols and the absorption of the complexed aflatoxin B1 is inhibited in rats.

Aflatoxin B1 (AFB1) is the most prevalent and carcinogenic form of the aflatoxins. In this report, we explored the interaction between AFB1 and oxidised tea polyphenols (OTP). Then, the influence of OTP on the absorption and toxicity of AFB1 in rats was investigated. We found that AFB1 can be complexed with OTP, and a transmembrane bidirectional transport experiment verified the absorption of complexed AFB1 (C-AFB1) was inhibited by OTP dramatically (P < 0.001). Animal experiments results showed that the AFB1 plus OTP group had significantly (P < 0.05) decreased AFB1-albumin (AFB1-alb) compared to the AFB1 group at 4 h after ingestion. OTP could significantly (P < 0.01) promote the elimination of AFB1 in faeces. Moreover, the liver injury induced by AFB1 was significantly inhibited by OTP. Our results demonstrated AFB1 can be complexed with OTP and the absorption of the C-AFB1 is inhibited in rats. Consequently, the liver injury induced by AFB1 can be inhibited by OTP. These results provide insight that consuming OTP-containing products, like fermented Pu-er tea, can protect damage from AFB1, and OTP may be used as a kind of food additive. © 2016 Society of Chemical Industry.