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Dimiņš, Fredijs, Velga Miķelsone et Miķelis Kaņeps. « Antioxidant Characteristics of Latvian Herbal Tea Types ». Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences 67, no 4-5 (1 novembre 2013) : 433–36. http://dx.doi.org/10.2478/prolas-2013-0067.
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Abstract The aim of the study was to characterise antioxidative properties and antiradical activity of the herbal tea collection in Latvia. High-pressure liquid chromatography and spectrophotometry methods were used to characterise antioxidant properties of herbal tea. Antiradical activity was determined spectrophotometrically. The antiradical scavenging activity was measured by the DPPH (2,2-diphenyl-1-picrylhydrazyl) reaction. The herbal tea antiradical scavenging activity was estimated as the broken down quantity of DPPH on 100 grams of the herbal tea. Individual polyphenols in the herbal tea were identified and determined by liquid chromatography. Antiradical scavenging activity of the herbal tea was found to be 104 mol 100 g-1 tea. The following polyphenols were identified chromatographically in herbal tea: gallic, caffeic, chlorogenic, ferulic acids, rutin, catechin, vanillin, and epicatechin. Altogether 12 different varieties of herbal tea samples were analyzed. The results showed that different types of herbal tea substantially differed in composition. Polyphenol content of herbal teas was in the range of 1 mg in 100 g of tea up to 8 g per 100 g of tea. In the case of virus-related disease, infections and weakness of the organism, it is recommended to use tea with high content of rutin, as in Verbascum thapsiforme Schr., Alchemilla vulgaris L., Comarum palustre L. herbal tea.
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Yoo, Yang-Seok, et Hochul Jung. « Tea Concept and Tea Types Reflected in World Zen Tea Products ». Korean Tea Society 25, no 4 (31 décembre 2019) : 32–39. http://dx.doi.org/10.29225/jkts.2019.25.4.32.
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Erzsébet, Fogarasi, Fülöp Ibolya, Berecz Zsuzsa, Márton Kincső et Croitoru Mircea Dumitru. « Aluminium contamination of several types of tea ». Bulletin of Medical Sciences 92, no 1 (1 juillet 2019) : 42–46. http://dx.doi.org/10.2478/orvtudert-2019-0003.
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Abstract Introduction: Camellia sinensis, a widely used plant, optimally grows in a low pH soil that in most cases contains high amounts of aluminum. Objectives: The aluminum content of the tea obtained from Camellia sinensis and other plants was compared. The influence of pH on the aluminum content of the tea was also measured. Materials and methods: The aluminum content of 48 samples was measured using a colorimetric method. The method is based on the ability of aluminum to form a stable complex with xylenol orange at low pH; this complex has an absorption maximum of 555 nm. Results: The method was validated for tea obtained with water and for tea obtained with water containing citric acid. The method proved linear over the rage of 0.7 – 7 ug/ml, coefficient of variation ranged between 2.6 – 7.68% (was dependent on the pH of the solution used to obtain the tea), accuracy was suitable for quantitative measurement (92.39-102.92%) and the complex proved to be stable for at least 1 hour. The following concentrations were measured: green tea (1.59 - 7.70 µg/ml), black tea (1.39 - 5.60 µg/ml), fruit tea (1.01 - 5.63 µg/ml) and herbal tea (1.03 - 5.24 µg/ml). Conclusion: The method proved useful and easily applicable for screening aluminum content of plants used for tea brewing. Camellia sinensis both green and black types had significantly higher aluminum contents than other type of teas. Adding citric acid, as would result from use of lemon juice, significantly increased the aluminum extraction from the plants used for tea brewing.
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Matita, Intan Cidarbulan, Titri Siratantri Mastuti et Smita Maitri. « Antioxidant Properties of Different Types of Torbangun Herbal Tea ». Reaktor 20, no 1 (13 mars 2020) : 18–25. http://dx.doi.org/10.14710/reaktor.20.1.18-25.
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In this study, Torbangun leaves are processed into three different types varying in their oxidation degree, namely unoxidized, semioxidized and oxidized Torbangun leaves. Each type is then brewed into herbal tea and analyzed in terms of its total phenolic, total flavonoid and antioxidant activity. Unoxidized Torbangun herbal tea shows higher content of total phenolic (44.22 mg GAE/g) and total flavonoid (17.02 mg QE/g) compared to oxidized (24.66 mg GAE/g total phenolic content and 8.61 mg QE/g total flavonoid content) and semioxidized (33.83 mg GAE/g total phenolic content and 10.68 mg QE/g total flavonoid content) Torbangun herbal tea. In terms of the antioxidant activity, processing the Torbangun leaves into herbal tea tremendously decreased the antioxidant activity based on the IC50 value of 1400.89 ɥg/mL for unoxidized Torbangun herbal tea, 3211.71 ɥg/mL for semioxidized Torbangun herbal tea and 4504.78 ɥg/mL for oxidized Torbangun herbal tea. However, steam blanching used in the preparation of unoxidized Torbangun leaves is proven to increase the total phenolic and flavonoid content of raw or unprocessed Torbangun leaves from 39.02 to 44.22 mg GAE/g and an increase of total flavonoid from 10.32 to 17.02 mg QE/g.Keywords: antioxidant; flavonoid; herbal tea; phenolic; torbangun
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Fyda, Janusz, et Patrycja Żelazo. « Decomposition rate of two tea types in two different forestry niches ». Science, Technology and Innovation 15, no 1-2 (31 mars 2023) : 8–16. http://dx.doi.org/10.55225/sti.399.
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Organic matter decomposition is one of the most important processes associated with flow of energy and recirculation of organic matter in natural environments. Using commercially sold tea bags of Lipton Sencha green tea (SGT) and Lipton Ceylon black tea (CBT) their decomposition was studied in mixed and coniferous forest. At both stations 25 bags of each tea were buried for a period of 3 months. After elapsed time, the bags were dug up, dried, and the mean weight loss of organic material for each tea type and ecosystem was calculated. In the mixed forest the average weight loss of tea bags was 46.8% for Sencha and 32.1% for Ceylon tea and respectively 44.6% and 30.6%, in the coniferous forest. Statistical analysis test (ANOVA) revealed a statistically significant difference (p < 0.05) in rate of decomposition between tea types, however the differences between the decomposition of the same type of tea on both type of forest were insignificant.
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Sari, Putri Ardila, et Irdawati Irdawati. « Kombucha Tea Production Using Different Tea Raw Materials ». Bioscience 3, no 2 (31 octobre 2019) : 135. http://dx.doi.org/10.24036/0201932105584-0-00.
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Tea (Camellia sinensis) is an agricultural product that is widely issued by people around the world. Some types of tea in the world are green tea, black tea, oolong tea and white tea. Kombucha tea is brewed water for tea and sugar then given bacteria and fungi and fermented for 7-10 days. The purpose of this study was to determine the quality of kombucha of several different types and determine the organoleptic value of fermented kombucha tea using different types. This research was conducted in April-July 2019 in the Microbiology Laboratory of the Department of Biology FMIPA Padang State University. This research is an experimental study with 5 treatments and 1 repetition (K: kombucha starter, P1: kombucha starter + green tea, P2: kombucha starter + black tea, P3: kombucha starter + oolong tea, P4: kombucha starter + white tea. Parameters Calculated are the number of microbes, nata thickness, pH of kombucha tea, total acetic acid, and organoleptic tests of kombucha tea.The results of this study indicate differences in the types of tea used in kombucha fermentation, the quality of kombucha tea produced, kombucha tea using black tea. The organoleptic test requested by the panelists was kombucha tea from white tea.
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Nuryana, Isa, Shanti Ratnakomala, Fahrurrozi Fahrurrozi, Ario Betha Juanssilfero, Ade Andriani, Filemon Jalu Nusantara Putra, Erdiansyah Rezamela, Restu Wulansari, M. Iqbal Prawira Atmaja et Puspita Lisdiyanti. « Catechin Contents, Antioxidant and Antibacterial Activities of Different Types of Indonesian Tea (Camellia sinensis) ». ANNALES BOGORIENSES 24, no 2 (5 janvier 2021) : 106. http://dx.doi.org/10.14203/ann.bogor.2020.v24.n2.106-113.
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Tea is one of the most popular beverages in the world. Produced from Camellia sinensis leaves, tea has been studied to provide health benefits due to the content of important metabolites. This study aimed to investigate the catechin contents, antioxidant, and antibacterial activities of Indonesian tea varieties, namely green tea, black tea, and white tea. Tea infusion was prepared by extracting 1 g of each sample into 10 mL of distilled water and incubated at 80 °C for 60 min. The catechin and epigallocatechin gallate (EGCG) contents of tea extracts were determined using high-performance liquid chromatography (HPLC). Antioxidant activity was measured using the free radical method with 2,2-diphenyl-1-pycrylhidrazyl (DPPH), while antimicrobial activity was assesed using paper disc diffusion assay. The results indicated that green tea had the highest contents of catechin (646 ± 17.14 mg/L) and EGCG (997.8 ± 36.72 mg/L), and antioxidant activity with IC50 of 5.65 µg/mL. Furthermore, green tea and white tea extracts showed inhibitory activity against Gram-positive bacteria such as Micrococcus luteus, Bacillus subtilis, and Staphylococcus aureus whereas black tea had no activity against all bacterial strains tested. Generally, we concluded that white tea and green tea contributed to the higher content of catechins and exhibited strong antioxidant and antibacterial properties.
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Li, Zhangwei, et Juhong Wang. « Identification and similarity analysis of aroma substances in main types of Fenghuang Dancong tea ». PLOS ONE 15, no 12 (21 décembre 2020) : e0244224. http://dx.doi.org/10.1371/journal.pone.0244224.
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Fenghuang Dancong tea covers the oolong tea category and is widely acknowledged for its unique floral and honey flavor. In order to characterize the volatile components in nine different aroma types of Fenghuang Dancong tea, the Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC- MS) were employed. In addition, the similarity analysis and cluster analysis (CA) were performed to compare the aroma characteristics and establish the correlation between the nine types of teas. The principal component analysis (PCA) and orthogonal partial least squares discrimination analysis (OPLS-DA) method were employed to determine the volatile components with a high contribution to the overall aroma of each type of tea. The results presented a total of 122 volatile aroma components including 24 kinds of alcohol, 23 kinds of esters, 15 kinds of olefins, 12 kinds of aldehydes, 12 kinds of ketones, 13 kinds of alkanes and 23 kinds of other components from the nine types of Fenghuang Dancong tea. Of these volatile aroma components, 22 types were common with linalool, dehydrolinalool, linalool oxide I, linalool oxide II, etc. The similarity of the nine types of Fenghuang Dancong tea was found between 46.79% and 95.94%. The CA indicated that the nine types of Fenghuang Dancong tea could be clustered into four categories when the ordinate distance reached to 10. The PCA demonstrated that decane, octadecane, 2,2,4,6,6-pentamethylheptane, dehydrolinalool, geraniol and nerol were the important aroma components to Fenghuang Dancong Tea. OPLS-DA proved that 2,2,4,6,6-pentamethylheptane, dehydrolinalool, phenylacetaldehyde, nerolidol, linalool oxide I and hexanal were the key differential compounds between the various types of tea samples. This study provides a theoretical basis for characterizing the volatile aroma components in the main types of Fenghuang Dancong tea as well as the similarity and correlation between various types of Fenghuang Dancong tea.
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Antarini, Anak Agung Nanak, Ni Putu Agustini et I. Komang Agusjaya Mataram. « effect of using various tea types on the characteristics of wong tea balinese tradisional beverage ». International research journal of engineering, IT & ; scientific research 8, no 2 (23 février 2022) : 1–13. http://dx.doi.org/10.21744/irjeis.v8n2.2060.
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This study aimed to determine the effect of various types of tea solutions on the characteristics of Wong Tea. This study used a Randomized Block Design (RBD) of 4 treatments with various types of tea solutions with 4 replications. The results showed that there were significant differences in the organoleptic quality including the taste, aroma, and color of Wong tea. The results of the research on pH, total acid, alcohol content, and total soluble solid showed no significant difference. The pH of Wong tea ranged from pH 3.28 - pH 3.35, total soluble solid ranged from 13.90°Brix - 13.95°Brix, total acidity of Wong tea ranged from 1.58% - 1.72%. The alcohol content of Wong tea ranges from 0.33% - 0.41%. The results of this study also showed that there was a significant difference in antioxidant activity and phenol levels of Wong tea, i.e., the antioxidant capacity of Wong tea ranged from 6.50% - 7.30%. The components that act as antioxidants in Wong tea ingredients come from phenolic compounds. Phenol levels in Wong tea ranged from 125.80 mg% - 141.10 mg%.
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Ismail, F. S., K. Yusoh, A. S. Zainal Abidin, A. H. Abdullah et Z. Ismail. « Three different types of tea as surfactant in liquid exfoliation of graphite : green tea, black tea and oolong tea ». IOP Conference Series : Materials Science and Engineering 702 (7 décembre 2019) : 012036. http://dx.doi.org/10.1088/1757-899x/702/1/012036.
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Kaur, Amandeep, Sumaya Farooq et Amit Sehgal. « A Comparative Study of Antioxidant Potential and Phenolic Content in White (Silver Needle), Green and Black Tea ». Current Nutrition & ; Food Science 15, no 4 (28 juin 2019) : 415–20. http://dx.doi.org/10.2174/1573401313666171016162310.
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Background: White, green and black are the major tea types obtained from the same tea plant (Camellia sinensis). The differences in processing result in different types of tea, of which green tea (20%) and black tea (78%) are the most consumed worldwide and also white tea is gaining popularity due to its subtle taste and recent evidences about its health benefits. Silver needle is a sub type of white tea, made purely from buds whereas green tea is procured from leaves that are steamed or panfried, and to produce black tea, the tea leaves are withered, fully oxidized and then dried. Objective: The present study was undertaken to analyze and compare the antioxidant activity and phenolic composition of white (silver needle), green and black teas of same brand. Method: The radical scavenging ability of different tea types was measured using various antioxidant assays. The total phenolic content was also estimated using Folin-Ciocalteu’s method. Results: The white tea (silver needle) demonstrated highest radical scavenging activity followed by green and then black tea in various antioxidant assays performed. The total phenolic content of different types of tea exhibited the following order: white tea (133.30mg/g) > green tea (118.37mg/g) > black tea (101.8mg/g). A strong correlation was observed between the total phenolic content and antioxidant activity of different tea types, the correlation coefficient ranged from 0.87-0.97. Conclusion: White tea (silver needle) manifested highest antioxidant activity followed by green and least in black tea. The pronounced antioxidant ability of WT (silver needle) may be ascribed to the different parts of the plant (unopened buds) and the least processing it undergoes, followed by obtaining green tea and black tea from different parts of the plant (leaves), and variation in degree of processing.
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Hu, Wenwen, Gege Wang, Shunxian Lin, Zhijun Liu, Peng Wang, Jiayu Li, Qi Zhang et Haibin He. « Digital Evaluation of Aroma Intensity and Odor Characteristics of Tea with Different Types—Based on OAV-Splitting Method ». Foods 11, no 15 (25 juillet 2022) : 2204. http://dx.doi.org/10.3390/foods11152204.
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Aroma is one of the most important quality indicators of tea. However, this evaluation method is a subjective one. In this study, the volatiles of tea with 5 types were determined by headspace solid-phase micro-extraction (HS-SPME) combined with gas chromatography mass spectrometry (GC-MS). The aroma intensity and odor characteristics of teas were comparatively analyzed based on the OAV-splitting method. The results showed that OAV were green tea (492.02), red tea (471.88), oolong tea (302.74), white tea (68.10), and dark tea (55.98). The odor index I(o) indicated that green tea was strong-flavor tea with highlight green accompanied by fruity, woody and fatty odors; oolong tea was strong-flavor tea with fruity and fatty accompanied by woody, floral and green odors; red tea was strong-flavor tea with highlight fruity accompanied by woody, green and floral odors; white tea was a light-flavor tea with floral, woody and green odors; and dark tea was light-flavor tea with woody and floral notes accompanied by fatty and green odors. These results fitted perfectly with the people’s consensus on these teas, and proved that the OAV-splitting method is feasible to evaluate the aroma intensity and odor characteristics of tea aroma. We suggest that the digital evaluation of tea aroma can facilitate people’s communication.
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Sarkar, Satyajit, Anurag Chowdhury, Sanjay Das, Bhaskar Chakraborty, Palash Mandal et Monoranjan Chowdhury*. « Major tea processing practices in India. » International Journal of Bioassays 5, no 11 (31 octobre 2016) : 5071. http://dx.doi.org/10.21746/ijbio.2016.11.0015.
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Tea is the most popular beverage in the world and is the economical backbones of some countries like India, China, Kenya, Sri Lanka etc. Indian tea is very much popular among the world, specially Darjeeling tea which is famous for its flavour and taste. Among the various types of tea, orthodox tea is highly demandable for its quality. The present paper deals with various types of tea processing in India. Mainly three types of tea processing are practices in India. Among these, CTC tea processing is more common in Indian sub-continent followed by Green tea and Orthodox tea. In this paper, details manufacturing process and step wise pictorial viewed are presented. All the data are extracted from different world famous tea gardens of Darjeeling, terai and duars of Northern West Bengal.
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KONDO, Takahide, Ayaka WATANABE, Hiroshi SHITARA, Yasuo KABURAGI, Masahisa SHIBATA, Noriko KANDA, Chieko KUROKAWA et al. « Residual Pesticide Concentrations in Tea after Processing to Various Types of Tea and in Tea Infusions ». Food Hygiene and Safety Science (Shokuhin Eiseigaku Zasshi) 54, no 4 (2013) : 259–65. http://dx.doi.org/10.3358/shokueishi.54.259.
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Rizhon, Rizhon, et Siska Amelia Maldin. « The Influence Of Tea Types In Making Kombucha On The Taste And Preference Of Hoteliers In Batam ». Jurnal Indonesia Sosial Teknologi 4, no 10 (25 octobre 2023) : 1749–60. http://dx.doi.org/10.59141/jist.v4i10.752.
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Kombucha is a popular drink with its benefits for human health. This tea-based drink is very famous in the world of tourism for its sour and refreshing taste. Kombucha is generally made using green tea or black tea. However, many types of tea can be used, such as white tea, oolong tea, and so on. Usually, kombucha is made using tea, sugar, and water, then given bacteria and fungi to ferment for around 7 – 15 days. This research aims to see how the use of tea as a basic ingredient affects the taste and preferences of hoteliers in Batam, where 15 panelists carried out organoleptic tests on 8 samples of kombucha that have been prepared, where the only differentiating variable is the type of tea used, the results found that kombucha that is made from green tea is most liked by the panelists, meanwhile, the kombucha that is made from black tea is least liked.
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Issaliyeva, M. A., Z. B. Yessimsiitova, Y. A. Sinyavskiy et D. N. Tuigunov. « DEVELOPMENT OF NEW TYPES OF TEA DRINKS WITH TARGETED PREVENTIVE PROPERTIES ». Bulletin of Shakarim University. Technical Sciences, no 1(13) (29 mars 2024) : 133–42. http://dx.doi.org/10.53360/2788-7995-2024-1(13)-17.
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Recently, interest in the production of tea and tea drinks has increased due to its nutritional and medicinal properties. The composition of tea is complex and is still not fully understood. Therefore, the development of new technology of tea and functional tea drinks opens a unique opportunity for domestic manufacturer to produce competitive products.In this study the technology of three types of tea drinks based on raw components of fruits, berries and medicinal plants «Antioxidant», «Immunostimulating», «Cardiovascular» with targeted preventive properties was developed, where the physicochemical, mineral composition and organoleptic parameters were studied.The results of the analysis showed that the highest concentrations of vitamin C (mg/100 g) were found in sea buckthorn fruits (215.7±18.4), black currant fruits (196.5±14.3), melissa leaves (100.1±9.9), lemon peel (90.5±8.4) and Goji berries (49.5±3.8). High β-carotene content (mg/100 g) was observed in Goji berries, lemon balm leaves and sea buckthorn fruits – 91.3±7.6; 47.2±3.6 and 33.7±2.9 mg/100 g, respectively. In addition, fruits, berries and medicinal plants selected as raw components had high levels of flavonoids, xanthophylls, tocopherols, phenolic compounds and other biologically active substances. Cranberry berries (44.8±3.2), Goji berries (31.0±2.6), black tea leaves (25.4±1.9), black currant fruits (21.6±1.2) and peppermint leaves (15.2±1.1) had high levels of total antioxidants (mg/100 g) due to the increased content of catechins, anthocyanins, carotenoids, vitamin C, tannin and bioflavonoids, contributing to the reduction of oxidative stress and protecting cells from the destructive effects of free radicals. Prophylactic tea blends have been studied and shown to have high taste, fine exquisite aroma and actively stimulating and therapeutic properties, according to the created formulations, taking into account antioxidant immunostimulating activity.
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Grużewska-Piotrowska, Kinga, Monika Pająk, Joanna Hubka, Agnieszka Grużewska et Wojciech Wcisło. « Benefits and disadvantages of drinking different types of tea – awareness of people based on anonymous surveys ». Journal of Education, Health and Sport 46, no 1 (25 août 2023) : 35–63. http://dx.doi.org/10.12775/jehs.2023.46.01.003.
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Introduction: Tea comes from ancient China and it is obtained from the leaves of the plant known as Camellia sinensis. It can be distinguished six categories of the tea: white, green, yellow, black, oolong, pu-erh (dark, fermented) depending on the complex production processes. Tea contains various bioactive ingredients that have beneficial effects on health. In addition, tea drinking is considered safe for humans as severe side effects from ingestion of tea infusion or extract are rarely observed.
The aim of the study: The aim of the study was to assess the level of knowledge among people about bioactive ingredients, different types of tea, health benefits, safety issues and disadvantages of drinking tea based on anonymous surveys.
Materials and methods: The research material was collected using an anonymous survey in June 2023. The obtained results were analyzed and verified on the basis of scientific literature and statistically processed using Microsoft Office Excel.
Discussion and conclusions: 97% of respondents drink tea, and 59.3% of people reach for it every day. The most commonly consumed type is green tea. 58.6% of respondents believe that tea may have health properties, and 80.9% believe that tea is not harmful to health. Tea contains numerous bioactive ingredients, including: polyphenols, polysaccharides, aminoacids, alkaloids, saponins, enzymes, minerals. They are responsible for a number of functions affecting human health, including: antioxidant, anti-inflammatory, immunoregulatory, anti-cancer, cardiovascular, anti-diabetic, anti-obesity and liver-protective properties. In tea, the bioavailability of active ingredients depends on the method of brewing, but also on the type of tea. Despite the many benefits, attention should be paid to the contamination of tea with heavy metals, pesticides and mycotoxins, and to excessive consumption of substances such as caffeine, as they can cause side effects observed in studies.
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Al-Zubaidi, Ez al-Din Khazal Najm. « The catechins profile and antioxidant activity in different types of green tea bags ». Journal of Misan Researches 16, no 31 (15 juillet 2021) : 279–98. http://dx.doi.org/10.52834/jmr.v16i31.32.
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Tea and mainly green tea as a rich source of antioxidants has been widely known for some time. The antioxidant capacity of tea including green tea is mainly due to its catechins content. The objective of this study was to determine the relationship between the ORAC value and the catechins content. Regular and decaffeinated commercial green tea bags commonly consumed in the United Kingdom (UK) have been examined using Reversed-Phase High-pressure Liquid Chromatography (RP-HPLC). Teabags were purchased from different local supermarkets in the UK and extracted with natural mineral water at temperature 100°C for 9 minutes at the pre-adjusted pH 4. The level of four catechins (Epi-structured) for the thirteen types of green tea were separated and determined by HPLC analysis, i.e. ()-epigallocatechin (EGC), ()-epicatechin (EC), ()-epigallocatechin-3-gallate (EGCG) and ()-epicatechin gallate (ECG). The standard graphs were validated using certified reference catechins supplied by the Laboratory of the Government Chemist (LGC). The levels of total catechins and oxygen radical absorbance capacity (ORAC) values varied from 34.61to 204.55 mg/g, 830.19- 4197.81 Trolox equivalents/g tea bags for thirteen types of green teas respectively. It was clear from the results of this study that there was a significant linear and positive correlation (r = 0.951, df = 12, p < 0.05) is found to exist between the total catechins contents and ORAC values. It can be concluded that the results of catechins measurements coupled to this; the well-known ORAC assay was successfully modified to measure the antioxidant capacity of the green tea extracts throughout this study. Furthermore, the higher the level of catechins the higher is the antioxidant capacity of the tea. This may stimulus consumers in selecting the type of tea and tea brewing times, exhibiting more health benefits. Nevertheless, the differences between the studied brands are owing to shelf life, production and storage conditions.
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Oh, Jeong-Ho, Chan-Yang Lee, Yeong-Eun Lee, So-Hee Yoo, Jin-Oh Chung, Chan-Su Rha, Mi-Young Park, Yong-Deog Hong et Soon-Mi Shim. « Profiling of In Vitro Bioaccessibility and Intestinal Uptake of Flavonoids after Consumption of Commonly Available Green Tea Types ». Molecules 26, no 6 (10 mars 2021) : 1518. http://dx.doi.org/10.3390/molecules26061518.
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The aim of this study was to profile the bioaccessibility and intestinal absorption of epicatechins and flavonols in different forms of green tea and its formulation: loose leaf tea, powdered tea, 35% catechins containing GTE, and GTE formulated with green tea-derived polysaccharide and flavonols (CATEPLUS™). The bioaccessibillity and intestinal absorption of epicatechins and flavonols was investigated by using an in vitro digestion model system with Caco-2 cells. The bioaccessibility of total epicatechins in loose leaf tea, powdered tea, GTE, and CATEPLUS™ was 1.27%, 2.30%, 22.05%, and 18.72%, respectively, showing that GTE and CATEPLUS™ had significantly higher bioaccessibility than powdered tea and loose leaf tea. None of the flavonols were detected in powdered tea and loose leaf tea, but the bioaccessibility of the total flavonols in GTE and CATEPLUS™ was 85.74% and 66.98%, respectively. The highest intestinal absorption of epicatechins was found in CATEPLUS™ (171.39 ± 5.39 ng/mg protein) followed by GTE (57.38 ± 9.31), powdered tea (3.60 ± 0.67), and loose leaf tea (2.94 ± 1.03). The results from the study suggest that formulating green tea extracts rich in catechins with second components obtained from green tea processing could enhance the bioavailability of epicatechins.
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Jeong, Ilyong, Juyoung Lee, Miah Kim, Daewoo Lee, Yeonmi Yang et Jaegon Kim. « Anticariogenic Effects of Different Types of Tea ». JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY 44, no 4 (30 novembre 2017) : 437–45. http://dx.doi.org/10.5933/jkapd.2017.44.4.437.
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Helilusiatiningsih, Nunuk, et Sumarji. « Sensory Test on 3 Types of Functional Beverages ». East Asian Journal of Multidisciplinary Research 2, no 10 (25 octobre 2023) : 4025–34. http://dx.doi.org/10.55927/eajmr.v2i10.6450.
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The research method used was a qualitative test consisting of a visual test (color) and a sensory test including aroma and taste. The research treatments were M1, M2, M3. The results of the study showed that were as follows: M1, Ginger Tea: color, aroma, taste tests, namely 4 people really liked it, 14 people liked it, 2 people didn't like it; M2, Lemongrass tea: Color test, aroma test, namely 2 people really like it, 17 people like it, 1 person doesn't like it, the taste test shows 2 people really like it, 16 people like it and 2 people don't like it; M3, Lemongrass ginger tea: color, aroma, taste test yielded 13 people really liked it, 6 people liked it, 1 person didn't like it. So the functional drink most preferred by consumers was M3.
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Mohale, Keletso C., Araya T. Hintsa, Machel A. Emanuel et Fhatuwani N. Mudau. « Metabolic Profiling of Cultivated Bush Tea (Athrixia phylicoides DC.) in Response to Different Pruning Types ». HortScience 53, no 7 (juillet 2018) : 993–98. http://dx.doi.org/10.21273/hortsci13023-18.
Texte intégralRésumé :
Bush tea (Athrixia phylicoides DC.) is a popular medicinal South African indigenous plant and it has been used for many decades as a health beverage and medicine. The objective of the study was to profile metabolites for assessment of quality of bush tea (A. phylicoides DC.) subjected to different pruning levels. Treatments consisted of untreated control, top-branch pruning, middle pruning, and basal pruning arranged in a randomized complete block design (RCBD) using 10 single trees as replications. The liquid chromatography quadrupole time-of-flight mass spectrometry (LC–QTOF–MS) was carried out to annotate the bush tea metabolites present in bush tea. Orthogonal partial least square-discriminatory analysis (OPLS-DA) from 1H nuclear magnetic resonance (NMR) revealed a separation between the basal, middle, top pruning, and the unpruned bush tea plants. The pruned (top) and unpruned tea plants, exhibited higher levels of metabolites than the basal and middle pruned. Pruning bush tea showed a significant effect on accumulation of secondary metabolites and thus could enhance bush tea quality. The study successfully annotated 28 metabolites (compounds), which elucidated canonical differences in pruning treatment of bush tea, as validated through multivariate analysis. Top pruning (apically pruned) resulted in improved metabolite accumulation than other treatment and can be recommended in bush tea cultivation. Future studies to enhance vegetative enhancement after pruning will be evaluated.
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Lee, Tzan-Chain, Qian-Nan Zang, Kuan-Hung Lin, Hua-Lian Hu, Ping-Yuan Lu, Jing-Yao Zhang, Chun-Qin Kang, Yan-Jie Li et Tzu-Hsing Ko. « An Improved Method of Theabrownins Extraction and Detection in Six Major Types of Tea (Camellia sinensis) ». Journal of Chemistry 2022 (27 septembre 2022) : 1–9. http://dx.doi.org/10.1155/2022/8581515.
Texte intégralRésumé :
Tea pigments consisting of theabrownins (TBs), theaflavins (TFs), and thearubigins (TRs) affect the color and taste of tea. TBs include a variety of water-soluble compounds, but do not dissolve in n-butanol and ethyl acetate. Previously, the traditional method of TB extraction only mixed tea with n-butanol, and TBs were retained in the water phase. However, without ethyl acetate extraction, TFs and TRs remained in the water phase and affected the detection of TB content. Although an improved method had been devised by adding an ethyl acetate extraction step between tea production and n-butanol extraction, the proportional equation for calculating TB content (%) was not yet developed. In this study, we compared the absorbance at 380 nm (A380) of TB solutions from six major types of tea (green, yellow, oolong, white, black, and dark teas) extracted by improved and traditional methods from the same tea samples. Significantly lower A380 values were obtained from TB solutions via the improved method compared to the traditional method for six major types of tea, and the highest and lowest slops in TB concentrations from A380 analyses were from dark tea and green tea, respectively. Moreover, newly developed equations for TB content in those six tea types extracted by the improved methods were also established.
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Lin, Yanping, Ying Wang, Yibiao Huang, Huanlu Song et Ping Yang. « Aroma Identification and Classification in 18 Kinds of Teas (Camellia sinensis) by Sensory Evaluation, HS-SPME-GC-IMS/GC × GC-MS, and Chemometrics ». Foods 12, no 13 (21 juin 2023) : 2433. http://dx.doi.org/10.3390/foods12132433.
Texte intégralRésumé :
Tea (Camellia sinensis) is one of the most popular beverages worldwide. Many types of tea products continuously emerge in an endless stream; so, the classification of tea becomes more difficult. Aroma is a vital indicator of tea quality. The present study deals with the identification of aroma compounds in 18 different kinds of tea belonging to three typical tea varieties, including green tea, oolong tea, and black tea, using GC-IMS and GC × GC-O-MS. Moreover, the clustering of all 18 tea samples and the in depth correlation analysis between sensory evaluation and instrumental data were performed using the PCA and OPLS-DA. The results revealed that in all 18 kinds of tea, a total of 85 aroma compounds were detected by GC-IMS, whereas 318 were detected by GC × GC-O-MS. The PCA result revealed that green tea, oolong tea, and black tea could be clearly separated based on their peak areas. The OPLS-DA result showed that a total of 49 aroma compounds with VIP value > 1.0 could be considered as the potential indicators to quickly classify or verify tea types. This study not only compared the aroma differences across different types of teas, but also provided ideas for the rapid monitoring of tea quality and variety.
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SAGAYA, ABDULQUADRI, ABDULLAHI ALANAMU ABDULRAHAMAN et ADERIKE ADEWUMI. « AUTHENTICATION OF SOME COMMERCIAL TEAS IN ILORIN, NORTH-CENTRAL, NIGERIA ». Romanian Journal of Biology - Plant Biology 68, no 1-2 (30 décembre 2023) : 41–49. http://dx.doi.org/10.59277/rjb-pb.2023.1-2.06.
Texte intégralRésumé :
Adulteration and substitution of herbal drugs are trending issue in the herbal industry, posing a serious threat to commercial natural product research. Anatomical and chemical studies were carried out on Camellia sinensis and 6 commercial tea samples using chemical maceration technique (C-tea, L-tea, T-tea, H-tea, N-tea and A-tea). C. sinensis has hypostomatic leaves with paracytic and anomocytic stomatal complex types and thick-cell wall. The plant also possessed non-glandular unicellular trichomes. The anticlinal wall pattern was straight and rectangular, and it is undulating on the adaxial surface. Anatomically, C-tea has paracytic and pericytic stomatal complex types and unicellular non-glandular and multicellular glandular trichomes. L-tea has paracytic and anomocytic with unicellular glandular and multicellular non glandular trichomes. Paracytic, polocytic and anisocytic stomatal complex types with unicellular glandular and multicellular non-glandular trichomes were observed in T-tea. Occurrence of paracytic and anomocytic stomata was observed in H-tea; paracytic and tetracytic stomata were present in N-tea while paracytic stomata were observed in A-tea with unicellular glandular trichomes. The chemical tests shown that Prussian blue was present in three commercial samples of black tea and turmeric was present in two commercial green tea samples. Anatomical studies revealed that four of the selected commercial tea samples shown traces of adulteration.
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Manchón, N., L. Mateo-Vivaracho, D. Arrigo M, A. García-Lafuente, E. Guillamón, A. Villares et M. A. Rostagno. « Distribution patterns of polyphenols and alkaloids in instant coffee, soft and energy drinks, and tea ». Czech Journal of Food Sciences 31, No. 5 (9 septembre 2013) : 483–500. http://dx.doi.org/10.17221/443/2012-cjfs.
Texte intégralRésumé :
A previously developed method of HPLC-DAD-Fl has been used for the determination of phytochemical profiles in different types of drinks: instant coffee, soft drinks, energy drinks, and different types of tea (green, white, black, and red tea). Using data on the concentrations of 20 main phytochemicals (phenolic acids, flavan-3-ols, flavonols, flavones, and alkaloids) it was possible to identify most of the sample types. Chlorogenic and caffeic acids, and caffeine are the main target compounds in instant coffee; in soft and energy drinks, only caffeine was found. Tea has a more complex phytochemical composition. Unfermented tea is mainly composed of flavan-3-ols and alkaloids, with a high caffeine concentration. Black tea is composed of alkaloids and low levels of flavan-3-ols, which are affected by oxidative reactions during the fermentation. Flavonols are present in lower concentrations in all kinds of teas. The identified phytochemical distribution patterns were used to correctly differentiate instant coffee, soft drinks, energy drinks, unfermented tea and fermented tea (within fermented tea, black tea from red tea can also be differentiated).
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Jakubczyk, Karolina, Justyna Kałduńska, Joanna Kochman et Katarzyna Janda. « Chemical Profile and Antioxidant Activity of the Kombucha Beverage Derived from White, Green, Black and Red Tea ». Antioxidants 9, no 5 (22 mai 2020) : 447. http://dx.doi.org/10.3390/antiox9050447.
Texte intégralRésumé :
Kombucha is a fermented tea beverage prepared as a result of the symbiotic nature of bacterial cultures and yeast, the so-called SCOBY (Symbiotic Cultures of Bacteria and Yeasts). Kombucha is characterised by rich chemical content and healthy properties. It includes organic acids, minerals and vitamins originating mainly from tea, amino acids, and biologically active compounds—polyphenols in particular. Kombucha is prepared mainly in the form of black tea, but other tea types are increasingly often used as well, which can significantly impact its content and health benefits. This work shows that the type of tea has a significant influence on the parameters associated with the antioxidant potential, pH, as well as the content of acetic acid, alcohol or sugar. Red tea and green tea on the 1st and 14th day of fermentation are a particularly prominent source of antioxidants, especially polyphenols, including flavonoids. Therefore, the choice of other tea types than the traditionally used black tea and the subjection of these tea types to fermentation seems to be beneficial in terms of the healthy properties of kombucha.
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Wang, Chen, Jiaxing Liu, Siyao Sang, Xue Ao, Mingjie Su, Binwei Hu et Hui Li. « Effects of Tea Treatments against High-Fat Diet-Induced Disorder by Regulating Lipid Metabolism and the Gut Microbiota ». Computational and Mathematical Methods in Medicine 2022 (29 mai 2022) : 1–12. http://dx.doi.org/10.1155/2022/9336080.
Texte intégralRésumé :
High-fat diet (HFD) may induce changes of metabolism and gut microbiota changes, and these changes are susceptible to diet adjustments such as tea treatment. However, the treatment effects may vary among different types of tea. In this study, we evaluated the effects of six types of tea on glucose and lipid metabolism and gut microbiota in HFD mice. We established HFD mouse model by 12 weeks feed with 60% fat diet, then treated with teas for six weeks. Here, we showed that treatment with different types of tea can inhibit weight gain and insulin resistance though different ways. Green tea regulated lipid metabolism by regulating the expression of adenosine 5 ′ -monophosphate-activated protein kinase (AMPK) and carnitine palmitoyltransferase-I (CPT-1). The effect of dark tea and white tea in reducing liver weight seemed to be related to activities of acetyl-CoA carboxylase (ACC). Yellow tea exhibited the best anti-inflammatory and antioxidant effects and effects of recovering the disorder of model mouse microbiota. The decrease in blood sugar and the upregulation of gluconeogenesis-related enzymes seemed to be related to the decrement of unclassified Lachnospiraceae. These different effects may result from the unique chemical compositions contained by different types of tea, which can regulate different lipid and glucose metabolism-related proteins. Despite variations in its compositions and metabolic reactions, tea is a potent antiobesity and hypoglycemic agent.
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Zheng, Fang, Kelie Chen, Jiamin Zhong, Song Tang, Sinan Xu, Weiguo Lu, Yihua Wu et Dajing Xia. « Association between Different Types of Tea Consumption and Risk of Gynecologic Cancer : A Meta-Analysis of Cohort Studies ». Nutrients 15, no 2 (13 janvier 2023) : 403. http://dx.doi.org/10.3390/nu15020403.
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Plenty of studies have shown that tea has an effect of inhibiting gynecologic tumors. However, there still remained controversy of the association between tea and gynecologic tumors in epidemiological studies. In this study, PubMed, Embase, and Cochrane Database were used to search the literature from 1 January 1960 to 26 December 2022 to investigate the association between tea intake and gynecologic cancer risk. In total, 19 cohort studies with 2,020,980 subjects and 12,155 gynecological tumor cases were retrieved. The pooled relative risk (RR) of gynecologic tumor for tea intake was 1.00 (95% CI: 0.96–1.04). RRs were 0.94 (95% CI: 0.88–1.01) for ovarian cancer, 1.02 (95% CI: 0.97–1.07) for endometrial cancer, and 1.06 (95% CI: 0.91–1.23) for cervical cancer. Subgroup analyses were adopted based on the tea type and geographic location. Interestingly, significant preventive impact of non-herbal tea on ovarian cancer (pooled relative risk: 0.67; 95% CI: 0.55–0.81) was found, especially for black tea (pooled relative risk: 0.64; 95% CI: 0.51–0.80). Dose–response analysis indicated that although it is not statistically significant, a decreasing trend of ovarian cancer risk could be observed when the tea consumption was 1.40 to 3.12 cups/day. In conclusion, our findings suggested that ovarian cancer, but not other gynecologic cancers, could possibly be prevented by drinking non-herbal tea. In addition, the preventive impact of green tea on gynecologic cancer seemed to be relatively weak and needs further cohorts to validate it.
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Wang, Jinmei, Peichao Zheng, Hongdi Liu et Liang Fang. « Classification of Chinese tea leaves using laser-induced breakdown spectroscopy combined with the discriminant analysis method ». Analytical Methods 8, no 15 (2016) : 3204–9. http://dx.doi.org/10.1039/c5ay03260a.
Texte intégralRésumé :
Six types of tea leaves, including Longjing green tea, Mengding Huangya, white tea, Tie Guanyin, Wuyi black tea and Pu'er tea, were analyzed and identified using laser-induced breakdown spectroscopy (LIBS) combined with the discriminant analysis (DA) method.
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Huang, Danyi, Zhuang Bian, Qinli Qiu, Yinmao Wang, Dongmei Fan et Xiaochang Wang. « Identification of Similar Chinese Congou Black Teas Using an Electronic Tongue Combined with Pattern Recognition ». Molecules 24, no 24 (12 décembre 2019) : 4549. http://dx.doi.org/10.3390/molecules24244549.
Texte intégralRésumé :
It is very difficult for humans to distinguish between two kinds of black tea obtained with similar processing technology. In this paper, an electronic tongue was used to discriminate samples of seven different grades of two types of Chinese Congou black tea. The type of black tea was identified by principal component analysis and discriminant analysis. The latter showed better results. The samples of the two types of black tea distributed on the two sides of the region graph were obtained from discriminant analysis, according to tea type. For grade discrimination, we determined grade prediction models for each tea type by partial least-squares analysis; the coefficients of determination of the prediction models were both above 0.95. Discriminant analysis separated each sample in region graph depending on its grade and displayed a classification accuracy of 98.20% by cross-validation. The back-propagation neural network showed that the grade prediction accuracy for all samples was 95.00%. Discriminant analysis could successfully distinguish tea types and grades. As a complement, the models of the biochemical components of tea and electronic tongue by support vector machine showed good prediction results. Therefore, the electronic tongue is a useful tool for Congou black tea classification.
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Winiarska-Mieczan, Anna, et Ewa Baranowska-Wójcik. « The Effect of Brewing Time on the Antioxidant Activity of Tea Infusions ». Applied Sciences 14, no 5 (29 février 2024) : 2014. http://dx.doi.org/10.3390/app14052014.
Texte intégralRésumé :
Many studies have found that tea has an antioxidant, anti-inflammatory, anti-cancer, anti-obesogenic and anti-diabetic effect, mostly associated with the content of anti-oxidant compounds. Polyphenols, being the main secondary metabolites in tea, are often considered the physiological markers determining a tea’s quality. Apart from the tea production process and tea components, brewing conditions can also influence the levels of antioxidants in tea. This study aimed to verify whether the brewing time of various tea types (5, 10 and 15 min) affects the level of extraction of antioxidant compounds into infusions and their antioxidant activity. We examined 11 types of tea: green leaf tea, green tea bags, white tea bags, black tea bags, red tea bags, black leaf tea, yerba mate, raspberry tea bags, butterfly pea flower (Clitoria ternatea) tea, white lychee plum tea and hibiscus flower tea. Total polyphenol (TPC), flavonoids and anthocyanins content, as well as determination of antiradical and antioxidant capacity with DPPH radical and ABTS radical cation, were determined using spectrophotometric assays. Due to the antioxidant activity of tea infusions, the optimum brewing time for green tea (leaf and bags), black tea (leaf and bags), butterfly pea flower tea, white tea, white lychee plum tea, raspberry tea and yerba mate is 15 min. Red tea brewing time should be ten minutes, and for hibiscus flower tea it should be five minutes. The results refer to the brewing temperature recommended by tea manufacturers.
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Karori, M. S, Wachira, N. F, Wanyoko, K. J, Ngure et M. R. « Antioxidant capacity of different types of tea products ». African Journal of Biotechnology 6, no 19 (4 octobre 2007) : 2287–96. http://dx.doi.org/10.5897/ajb2007.000-2358.
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Pan, Junxian, Yulan Jiang, Yangjun Lv, Man Li, Shikang Zhang, Jun Liu, Yuejin Zhu et Haihua Zhang. « Comparison of the main compounds in Fuding white tea infusions from various tea types ». Food Science and Biotechnology 27, no 5 (23 mai 2018) : 1311–18. http://dx.doi.org/10.1007/s10068-018-0384-3.
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Sadeghnezhad, Reza, Seyyed Abbas Hashemi et Mohammad Zahedi. « Concentration of Fluoride in Different Types of Common Tea and Tea Bag in Iran ». International Journal of Medical Reviews 5, no 3 (30 septembre 2018) : 90–93. http://dx.doi.org/10.29252/ijmr-050302.
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Wu, Mu-Chen, Shih-Lun Liu, Bo-Kang Liou, Chun-Yeh Chen et Yuh-Shuen Chen. « Investigation on the Quality of Commercially Available GABA Tea in Taiwan ». Standards 3, no 3 (28 août 2023) : 297–315. http://dx.doi.org/10.3390/standards3030022.
Texte intégralRésumé :
This study collected 220 commercially available samples of γ-Aminobutyric acid (GABA) tea produced in Taiwan from 2016 to 2021. The 220 tea samples were categorized into five types of GABA tea, including 108 GABA Oolong tea, 71 GABA Black tea, 21 GABA Paochong tea, 12 GABA Green tea, and 8 GABA Puerh tea samples. The most common type of GABA tea in Taiwan is GABA Oolong tea, followed by GABA Black tea. The physico-chemical constituents and consumer acceptance of the GABA tea samples were analyzed. The GABA content varied among the different types of GABA tea: GABA Oolong tea ranged from 128–286 mg/100 g, GABA Black tea ranged from 182–360 mg/100 g, GABA Paochong tea ranged from 98–203 mg/100 g, GABA Green tea ranged from 56–174 mg/100 g, and GABA Puerh tea ranged from 142–191 mg/100 g. In terms of the commercial standard of GABA tea, 22 out of the 220 GABA tea samples failed to meet the commercial standard, with a failure rate of 10%. During the fermentation process of GABA tea, the contents of GABA increased significantly, but the total polyphenol and total catechin contents remained stable. In terms of consumer acceptance, GABA Black tea is the most accepted by consumers, followed by GABA Puerh tea, GABA Paochong, and GABA Oolong tea. The sour flavor in GABA tea is similar to the original sour sensory properties found in black tea. It is assumed that this is the main reason GABA Black tea has the highest acceptance.
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Mamatova, Maxfuza. « GENERAL CHARACTERISTIC OF TEA IN THE MARKETS OF TURKESTAN IN THE XIX-XX CENTURIES ». JOURNAL OF LOOK TO THE PAST 16, no 2 (30 août 2019) : 55–60. http://dx.doi.org/10.26739/2181-9599-2019-16-09.
Texte intégralRésumé :
This article deals with the general description of tea in the markets of Turkestan,provides an overview of the history of our country in the XIX-XX centuries, which based on archival materials and sources. This article tells about the types and varieties of tea consumed by our people, about the different types of tea that replace tea, where they were brought from, the meanings of their historical names and the consumption that was loved by our people.
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Setyaningrum, Kurnianti kumala, Nanik Suhartatik et Yannie Asrie Widanti. « Antioxidant Activity of Rose Tea (Rosa damascene) with Various Types of Sugar and Rose Tea Concentration ». JITIPARI (Jurnal Ilmiah Teknologi dan Industri Pangan UNISRI) 8, no 2 (2 septembre 2023) : 106–17. http://dx.doi.org/10.33061/jitipari.v8i2.7347.
Texte intégralRésumé :
Kombucha tea is a traditional beverages product manufactured from fermented tea and sugar solutions. Using Acetobacter xylinum sa starter. Kombucha tea has a refreshing sour taste, but the distinctives aroma make kombucha tea less attractives to consumers. Red roses (Rosa damascene) are a source of anthocyanin pigments that have not been widely used. In addition, to increase the economic value of roses. Based on research that has been done, red roses contain antioxidants in the form of purplish red anthocyanins. The purpose of this study was to determine the effect of the type of sugar and the concentration of rose extract on the characteristics of rose kombucha produced. This study used Completely Randomized Design (CRD). The factors used were the concentration of rose tea (1g/250ml, 2g/250ml, 3g/250ml) and variations in the type of sugar (palm, sand, fine). The best chemical and organoleptic analysis based on the highest antioxidant activity was the addition of palm sugar and the concentration of the addition of rose tea 1g/250ml with a total phenolic of 10.17mg GAE/L, total dissolved solids (TPT) 11.10%, acidity (pH) 3.86, antioxidant activity 48.28%, vitamin C 11.41%, 13.63% for total sugar, sour taste score 3.06, rose flavor 2.15 and 1.10 for overall preference the addition of palm sugar and the concentration of the addition of rose tea 1g/250ml. Kombucha made from rose extract can be an alternative functional food.
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Singh, Dharam, et Paramvir Singh Ahuja. « 5S rDNA gene diversity in tea (Camellia sinensis (L.) O. Kuntze) and its use for variety identification ». Genome 49, no 1 (1 janvier 2006) : 91–96. http://dx.doi.org/10.1139/g05-065.
Texte intégralRésumé :
Variability in the organization of repeats of 5S rDNA is useful for phylogenetic studies in various crops. We found variable repeats of 5S rDNA gene in the genome of tea (Camellia sinensis (L.) O. Kuntze) during Southern hybridization. Variability in the repeats of 5S rDNA with specific restriction endonuleases (Sau3AI, BamHI, and ApoI) was analyzed in 28 different tea clones representing 3 types of tea. Our results clearly show that the 5S rDNA gene in tea could be used as a molecular marker to distinguish C. sinensis Chinary tea from the other important types of tea, namely Assamica and Cambod. Upon analysis with restriction endonucleases, the 5S rDNA gene in the tea genome was found to be heavily methylated.Key words: Camellia sinensis, 5S rDNA, DNA methylation, restriction endonucleases, molecular marker.
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Komes, D., D. Horžić, A. Belščak, K. Kovačević Ganič et A. Baljak. « Determination of Caffeine Content in Tea and Maté Tea by using Different Methods ». Czech Journal of Food Sciences 27, Special Issue 1 (24 juin 2009) : S213—S216. http://dx.doi.org/10.17221/612-cjfs.
Texte intégralRésumé :
Caffeine-containing products have been consumed for hundreds of years for their pleasant flavor and stimulating effects. In recent years, caffeine received increasing attention in food and pharmaceutical industries, due to its pharmacological properties which comprise stimulation of the central nervous system, peripheral vasoconstriction, relaxation of the smooth muscle and myocardial stimulation. The aim of this study was to determine the content of caffeine in five types of tea (white, yellow, green, oolong, black) and two types of maté tea (green maté and roasted maté tea). The content of caffeine was determined by using four different methods: extraction with chloroform, micromethod, method with lead-acetate and high performance liquid chromatography method (HPLC-PDA). The antioxidant capacity of teas as well as of the extracted (“raw”) caffeine was determined by using two methods: reactions with 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical (ABTS assay) and Ferric reducing antioxidant power (FRAP assay). The content of caffeine has been associated with plant origin and growth conditions, as well as processing conditions. By applying all four methods, the highest content of caffeine was determined in white tea, whereas maté and roasted maté tea were characterised with the lowest content of caffeine. Spectrophotometric micro-method has proven to be the best alternative to the HPLC method. The highest antioxidant capacity was determined in yellow tea, while the lowest was determined in roasted maté tea. In comparison to the antioxidant capacity of teas, the antioxidant capacity of extracted (“raw”) caffeine is almost negligible, and does not contribute to the overall antioxidant properties of tea.
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Brodziak-Dopierała, Barbara, et Agnieszka Fischer. « Analysis of Mercury Content in Various Types of Tea (Camellia sinensis) and Yerba Mate (Ilex paraguariensis) ». International Journal of Environmental Research and Public Health 19, no 9 (1 mai 2022) : 5491. http://dx.doi.org/10.3390/ijerph19095491.
Texte intégralRésumé :
Due to the content of active ingredients, teas can be used prophylactically, but most of all they are consumed for taste reasons. As with food or water, these products can be contaminated with heavy metals, including mercury. Mercury (Hg) is a toxic element, it causes many side effects in the human body depending on the form of Hg, which can include respiratory failure, kidney damage, neurological disorders. At the cellular level, Hg and its compounds lead to a disturbance of metabolism and cell death. The aim of the study was to evaluate the mercury concentration of tea (Camellia sinensis) and Yerba Mate (Ilex paraguariensis). Eighty-six samples were collected and analyzed, including the following kinds: black, green, white, Pu-erh, and Yerba Mate. The samples came from Poland. The Hg concentration was determined with an AMA 254 atomic absorption spectrometer. The study showed that the Hg content in each tea sample averaged 2.47 μg/kg. The Hg concentration in the tested types of tea differed significantly statistically (p = 0.000). It was the largest in Yerba Mate, followed by green, Pu-erh, and white tea, and was the smallest in black tea. Statistically significant differences in the Hg content (p = 0.004) were also dependent on the form of the product; in leaf tea samples, the concentration of Hg (2.54 µg/kg) was higher than in tea bags (1.16 µg/kg). The Hg concentration determined in the tested samples does not exceed the permitted EU standard. Consuming these teas poses no health risk in terms of the amount of Hg.
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Valiulina, D. F., N. V. Makarova et D. V. Budylin. « Comparative analysis of the chemical composition and antioxidant properties of different types of tea as a raw material for the production of tea extracts ». Proceedings of the Voronezh State University of Engineering Technologies 80, no 2 (2 octobre 2018) : 249–55. http://dx.doi.org/10.20914/2310-1202-2018-2-249-255.
Texte intégralRésumé :
One of the most frequently consumed sources of natural antioxidants is tea. High content of phenolic substances in it, makes it an excellent functional drink. At present, interest in tea is great not only as an independent drink, but also as a raw material for the production of tea extracts. The study was conducted on extracts obtained from samples of leaf tea of foreign and Russian origin in the following parameters: the content of soluble solids in tea extracts; total content of phenolic substances; total content of flavonoids; total content of tannins; antiradical activity by the DPPH method; restoring force by the method of FRAP. During the study of tea species, different in the way of processing and in the region of origin, it was determined that the leader among the presented teas is the white tea of Chinese origin, which has the highest antiradical activity and the highest content of tannins. Comparing green tea from China and Russia, it can be concluded that the content of individual groups of substances varies slightly against the background of slightly higher anti-radical activity of Chinese tea. In the group of black teas, the Indian "Harmutti" tea is in the lead by the results of the test, significantly exceeding tea from the Krasnodar Territory by anti-radical activity and the total content of phenolic substances. Thus, promising types of tea for the prevention of diseases (diabetes, atherosclerosis, hypertension, Alzheimer's disease), arising as a consequence of oxidative stress, are tea white Chinese and green tea Krasnodar.
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Chabbert, C., J. M. Chambard, A. Sans et G. Desmadryl. « Three Types of Depolarization-Activated Potassium Currents in Acutely Isolated Mouse Vestibular Neurons ». Journal of Neurophysiology 85, no 3 (1 mars 2001) : 1017–26. http://dx.doi.org/10.1152/jn.2001.85.3.1017.
Texte intégralRésumé :
The nature and electrophysiological properties of Ca2+-independent depolarization-activated potassium currents were investigated in vestibular primary neurons acutely isolated from postnatal mice using the whole cell configuration of the patch-clamp technique. Three types of currents were identified. The first current, sensitive to TEA ( I TEA) and insensitive to 4-aminopyridine (4-AP), activated at −40 mV and exhibited slow activation ( τ ac, 38.4 ± 7.8 ms at −30 mV, mean ± SD). I TEA had a half activation potential [ V ac(1/2)] of −14.5 ± 2.6 mV and was inactivated by up to 84.5 ± 5.7% by 10-s conditioning prepulses with a half inactivation potential [ V inac(1/2)] of −62.4 ± 0.2 mV. The second current, sensitive to 4-AP (maximum block around 0.5 mM) and to α-dendrotoxin ( I DTX) appeared at −60 mV. Complete block of I DTX was achieved using either 20 nM α-DTX or 50 nM margatoxin. This current activated 10 times faster than I TEA( τ ac, 3.5 ± 0.8 ms at −50 mV) with V ac(1/2) of −51.2 ± 0.6 mV, and inactivated only slightly compared with I TEA (maximum inactivation, 19.7 ± 3.2%). The third current, also sensitive to 4-AP (maximum block at 2 mM), was selectively blocked by application of blood depressing substance (BDS-I; maximum block at 250 nM). The BDS-I–sensitive current ( I BDS-I) activated around −60 mV. It displayed fast activation ( τ ac, 2.3 ± 0.4 ms at −50 mV) and fast and complete voltage-dependent inactivation. I BDS-I had a V ac(1/2) of −31.3 ± 0.4 mV and V inac(1/2) of −65.8 ± 0.3 mV. It displayed faster time-dependent inactivation and recovery from inactivation than I TEA. The three types of current were found in all the neurons investigated. Although I TEA was the major current, the proportion of I DTX and I BDS-I varied considerably between neurons. The ratio of the density of I BDS-I to that of I DTX ranged from 0.02 to 2.90 without correlation with the cell capacitances. In conclusion, vestibular primary neurons differ by the proportion rather than the type of the depolarization-activated potassium currents they express.
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Sun, Lingli, Qiuhua Li, Limin Xiang, Xingfei Lai, Wenji Zhang, Ruohong Chen, Junxi Cao et Shili Sun. « Phytochemical Profiles and Bioactivities of Cake Tea Leaves Obtained From the Same Cultivar : A Comparative Analysis ». Natural Product Communications 15, no 8 (août 2020) : 1934578X2094550. http://dx.doi.org/10.1177/1934578x20945505.
Texte intégralRésumé :
Cake tea, a traditional beverage of China, has excellent health benefits. Our study investigated the phytochemical profiles, antioxidant, and antiproliferative activities of cake tea leaves, which were obtained from the same cultivar and processed at different intervals. The effects of bioactive compounds and antioxidant activities of 4 cake tea varieties on a human lung cancer cell line (A549 cells) were systematically examined. The content of total polyphenol, an active ingredient of tea, was significantly higher in green cake teas (14.0% ± 0.4a) than their black (4.8 ± 0.3c), yellow (10.0 ± 0.6b), and white (8.8 ± 0.5b) counterparts. Likewise, the content of total free amino acids in green cake tea (3.6% ± 0.5a) was significantly higher than the other tea varieties. Our results indicated that the extent of fermentation of tea leaves could decrease the antioxidant activities of cake tea leaves. Furthermore, the white tea cake variety demonstrated the maximum antiproliferative activity on A549 cells as opposed to other types of cake tea leaves. Such an observation allows future researchers to narrow down their focus on using specific cake tea types (sourced from the same cultivar) that provide the maximum health benefits.
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Hasan Abdulraheam, Rukhosh, et Balkees Taha Garib. « Effect of Different Tea in Remineralization of Artificially- Induced Initial Enamel Caries of Human Teeth (Study in Vitro) ». Tikrit Journal for Dental Sciences 1, no 1 (22 janvier 2024) : 19–24. http://dx.doi.org/10.25130/tjds.1.1.4.
Texte intégralRésumé :
One of the beneficial effects of consumption different types of tea is preventing tooth decay that attributed to their mineral contents. Purpose: to investigate the microscopical changes of different types of tea ; Camellia sinensis (black and green), Mentha spicata and Ocimum basilicum on artificially- induced initial enamel caries. Initial enamel caries-like lesions were introduced in 30 sound extracted human 1st premolar teeth using pH cycling procedure. Teeth were divided into 6 groups to test 4 types of tea ( black, green, Mentha spicata and Ocimum basilicum) and 2 control solutions (0.05%NaF and de-ionized water as positive and negative control respectively )for enamel re-mineralization, using polarized microscope. The concentration of calcium, inorganic phosphorous and fluoride ions in all tea solutions were also measured. Results revealed that green tea produced the best enamel remineralization, while black tea and Mentha spicata were coming next and result in different mode of re-mineralization. On the other hand, teeth treated Ocimum basilicum showed mild evidence of re-mineralization.The chemical analysis indicated that both Mentha spicata and Oci mum basilicum had the highest calcium and phosphorous ion s levels (higher than their fluoride concentration). Green tea had nearly equal concentration for the 3 tested ions, which were l ess than its counterpart black tea. All selected tea solutions were effective in remineralizing of initial enamel caries, in the following sequence: green tea, black / Mentha spicata , then Ocimum basilicum.
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Thapa, Anita. « Socio-economic Background of the Women Workers in Guranse Tea Estate, Dhankuta ». Geographic Base 6 (27 octobre 2019) : 87–96. http://dx.doi.org/10.3126/tgb.v6i0.26170.
Texte intégralRésumé :
Abundance of female workers in tea estate is common phenomena in the context of Nepalese tea industry. Women are main work force especially for leaf picking in any tea industry. So, the role of women participation is notable in this sector. This study focusses on socioeconomic background of women workers in Guranse Tea Estate, Dhankuta. Both qualitative and quantitative methods have been used to collect data and information through questionnaire, interview, focused group discussion, key informant interview and observation. Various types and nature of tea workers are found in the tea industry. Different types of socio-economic background such as caste/ethnicity, age group, educational status, land ownership, income level etc. have been found in this tea estate. Most of the workers are represented from indigenous and ethnic group with 20-40 age group. Similarly, a large number of tea workers are illiterate and landless as well as having low level of income.
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Carvalho, Elisabete, P. A. Nimal Punyasiri, H. P. P. Sudarshana Somasiri, I. Sarath B. Abeysinghe et Stefan Martens. « Quantification of γ-Aminobutyric Acid in Sri Lankan Tea by Means of Ultra Performance Tandem Mass Spectrometry ». Natural Product Communications 9, no 4 (avril 2014) : 1934578X1400900. http://dx.doi.org/10.1177/1934578x1400900426.
Texte intégralRésumé :
γ-Aminobutyric acid (GABA), an important bioactive component of tea, acts as a major inhibitory neurotransmitter and is considered to influence other physiological processes in human as well as in planta. In the hereby presented study, the content of this valuable metabolite was investigated in two novel types of Ceylon Tea, explicitly “Silver Tips” and “White Tea”, originating from minimally processed buds of the unique cultivar, “TRI 2043″. The samples were subjected to hot water infusion, equivalent to the traditional beverage preparation procedure, and analyzed by means of hydrophilic interaction ultra performance liquid chromatography coupled to tandem mass spectrometry (HILIC LC-MS/MS). The registered GABA levels were compared with those obtained for the classic “Black Tea” and “Green Tea” samples from Sri Lanka. A high variation of GABA content was observed among the different tea types, especially in the case of “Silver Tips” and “White Tea”, indicating the crucial influence of the manufacturing procedure (processing extent) on the final abundance of the bioactive component of interest. Furthermore, “White Tea” samples boasted the highest GABA concentration reported for this type of tea so far, reaching up to 50% of that characteristic of the high-priced “GABA Tea”. Therefore, “White Tea” and “Silver Tips” were proved to be high quality teas with amounts of γ-aminobutyric acid comparable with those described for similar types before. To our knowledge, this is the first report on HILIC LC-MS/MS application for the quantification of GABA and for in-depth characterization of teas from Sri Lanka.
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Carloni, Patricia, Federico Girolametti, Elisabetta Giorgini, Tiziana Bacchetti, Cristina Truzzi, Silvia Illuminati et Elisabetta Damiani. « Insights on the Nutraceutical Properties of Different Specialty Teas Grown and Processed in a German Tea Garden ». Antioxidants 12, no 11 (31 octobre 2023) : 1943. http://dx.doi.org/10.3390/antiox12111943.
Texte intégralRésumé :
European countries have recently started experimenting with growing and producing their own teas in small quantities, mainly for the specialty tea sector. To characterize European teas, this study investigated a set of five tea types obtained from different Camellia sinensis varieties/cultivars, representing various oxidation grades (green, white, yellow, oolong, black), all grown and processed in the only tea garden in Europe (in Germany) that focuses on all five types. Hot and cold brews were studied by measuring the total phenolic (TPC) and flavonoid contents (TFC), the antioxidant capacity and UV-Vis spectra, also with the objective of discriminating between the different tea types and the different plant varieties. The dried leaves were analyzed to measure the content of essential and toxic elements and by ATR-FTIR spectroscopy to determine a chemical fingerprint for identifying the tea varieties and types. The average levels of TPC (hot brew = 5.82 ± 2.06; cold brew = 5.4 ± 2.46 mM GAEq), TFC (hot brew = 0.87 ± 0.309; cold brew = 0.87 ± 0.413 mM CAEq), and antioxidant capacity (ORAC assay-hot brew = 20.9 ± 605; cold brew = 21.8 ± 8.0 mM TXEq, ABTS assay-hot brew = 15.2 ± 5.09; cold brew = 15.1 ± 5.8 mM TXEq, FRAP assay-hot brew = 9.2 ± 3.84; cold brew = 10.4 ± 5.23 mM AAEq) observed compared well with those from other parts of the world such as China, Africa, and Taiwan. The hazard quotient <1 and the hazard index of 0.14 indicate that there is no non-carcinogenic risk from consumption of these teas. The obtained information is essential for elucidating the characteristics and the impact of tea processing and tea variety on the health benefits of these tea products coming from a single European tea garden. This multifaceted approach would help tea growers in Europe increase their knowledge on the health attributes of the teas they grow, ultimately leading to optimization of the nutraceutical properties of these teas.
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Damhuji, Damhuji, Budi Suryana et M. Ibraar Ayatullah. « Antibacterial Effects of Steeped White Tea, Black Tea, and Green Tea against Streptococcus mutans and Plaque Accumulation ». Open Access Macedonian Journal of Medical Sciences 10, G (20 mars 2022) : 472–77. http://dx.doi.org/10.3889/oamjms.2022.8698.
Texte intégralRésumé :
BACKGROUND: Tea is the most consumed beverage in the world after water. Tea (Camellia sinensis) is native to Southeast Asia and is now available in more than 30 countries. Tea has various health properties. Tea has an active component, namely catechins, which can inhibit the growth of Streptococcus mutans as a component of dental plaque formation. AIM: This study aims to determine the antibacterial effect of steeped white tea, black tea, and green tea on S. mutans and plaque accumulation. METHODS: The research used a quasi-experimental design with pre-test and post-test group design. The population was students of the Department of Dental Nursing. Purposive sampling technique is used with a sample size of 48 students who were divided into three parts of the sample group for the 2.5% concentration of tea mouthwash treatment. The analysis used paired t-test to see the antibacterial effect and differences in three-variable test followed by Kruskal–Wallis test. RESULTS: The results showed that the mouth rinses of steeped white tea, black tea, and green tea were effective in reducing S. mutans and plaque accumulation on teeth. There is a significant difference in the inhibition zone of S. mutans against the three types of tea, and white has the largest inhibition zone. As for plaque accumulation, there is no difference between the three types of tea. CONCLUSIONS: It can be concluded that mouth rinsing with steeping white tea, black tea, and green tea with a concentration of 2.5% has antibacterial properties that can inhibit S. mutans and plaque accumulation.
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Hsieh, Yi, Ming-Chung Chiu et Jui-Yu Chou. « Efficacy of the Kombucha Beverage Derived from Green, Black, and Pu’er Teas on Chemical Profile and Antioxidant Activity ». Journal of Food Quality 2021 (8 novembre 2021) : 1–9. http://dx.doi.org/10.1155/2021/1735959.
Texte intégralRésumé :
Kombucha is a symbiotic culture of bacteria and yeast which produces a high-end fruity fitness beverage by fermentation of normal tea for approximately two weeks. In addition to the advantage of being a low-sugar probiotic-rich drink, kombucha also offers the benefits of the tea used for its preparation, especially its high antioxidant content. In this research, kombucha tea was prepared by using three different tea types: green, black, and pu’er tea, and the chemical profiles and antioxidant activity were analyzed during the fermentation process (up to 20 days). The results showed that the tea type has an obvious influence on the factors associated with the antioxidant potential. The fermentation process caused a marked increase in polyphenol content and antioxidant activity initially, but this slowed progressively over time. In contrast, the fermentation of black tea contributed to the degradation of flavonoids but showed no significant effect on the other tea types. Therefore, we conclude that the tea type selected to make kombucha affects the end product as well as the fermentation time.