Teas
Mostrando 1-12 de 60 artigos, teses e dissertações.
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1. Carbon Dots from Pilosocereus gounellei for Fluorimetric Determination of Tannin in Tea Using a Flow-Batch System
In this study, xiquexique (Pilosocereus gounellei) native endemic cactus from the Brazilian semiarid was used for the first time as a natural carbon source (“green precursor”) for the synthesis of highly fluorescent carbon dots (CDs). These CDs were successfully used to develop a fast, low-cost, eco-friendly fluorescence method for the determination of t
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. Determination of 3,4,5-Trihydroxybenzoic Acid Exploiting a Visible-Light-Driven Photoelectrochemical Platform: Application in Wine and Tea Samples
The present work is based on the development and application of a photoelectrochemical method for the amperometric determination of 3,4,5-trihydroxybenzoic acid in different samples. The method is based on the use of a photoelectrochemical platform based on a glass slide coated with fluorine-doped tin oxide, which has been modified with cadmium sulfide and p
Journal of the Brazilian Chemical Society. Publicado em: 2022
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3. Preoperative fasting for the infusion of “yerba mate”: a randomized clinical trial with ultrasound evaluation of gastric contents
Abstract Background The traditional infusion of “yerba mate” is widely consumed in South America and exported to countries around the world. Although generally considered a “clear fluid”, there is no data to date on the gastric emptying time of yerba mate and safe preoperative fasting intervals. The objective of this study was to evaluate the gastri
Brazilian Journal of Anesthesiology. Publicado em: 2022
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4. Determination of physical and chemical properties of kombucha teas prepared with different herbal teas
Abstract In this research, kombucha tea was prepared using 5 different tea extracts and physicochemical and sensory analyses were made. The tea extracts used are black tea, green tea, sage, linden and mint, respectively. The prepared tea samples were subjected to fermentation for 14 days. In tea samples, pH, electrical conductivity, water-soluble solid and p
Food Sci. Technol. Publicado em: 2021-06
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5. Determination of Total Antioxidant Capacity Using Thiamine as a Natural Fluorescent Probe
This work proposes a spectrofluorometric method for the determination of total antioxidant capacity (CAO) in beverage samples, based on inhibition of thiochrome formation (λex = 370 nm, λem = 440 nm); a product of thiamine (vitamin B1) oxidation from K3Fe(CN)6. In the development of the method, gallic acid (GA) was used as a reference, and inhibition of th
J. Braz. Chem. Soc.. Publicado em: 2020-12
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6. Comparison of total phenol content and antioxidant activity of herbal infusions with added Stevia reabaudiana Bertoni
Abstract Antioxidant capacity (AC) was determined by the ABTS method and DPPH, and total phenol content (TPC) in dehydrated plant material, in infusions and in residues (plant material after preparing the infusion) of white, black, red, green, spearmint, stevia, lemon grass and chamomile teas to which stevia leaves were added or not added; addition of proces
Food Sci. Technol. Publicado em: 2020-03
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7. Evaluation of α- and β-Endosulfan Residues in Teas and Yerba Mate Infusions by Bar Adsorptive Microextraction and Large Volume Injection-Gas Chromatography Mass Spectrometry
Tea and yerba mate are traditional beverages prepared through the infusion of leaves of Camellia sinensis and Ilex paraguariensis, respectively. During this process, the leaching of pesticides onto the beverage, such as endosulfan, may occur. In this study, a bar adsorptive microextraction (BAµE) method prior to large gas chromatography mass spectrometry an
J. Braz. Chem. Soc.. Publicado em: 2020-03
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8. PERFIL METABÓLICO DOS EXTRATOS POLARES DAS FOLHAS, GALHOS E CASCAS DE Copaifera multijuga HAYNE (COPAÍBA MARI-MARI DA AMAZÔNIA) POR ESI-EM
Copaifera multijuga Hayne is the main species of the genus in the Amazon region, being exploited for copaiba oil production mainly because of its therapeutic properties. The plant parts (leaves, branches, and barks) are widely used in folk medicine. However, they are little explored in terms of chemical composition. In this study, the polar extracts of leave
Quím. Nova. Publicado em: 2020-01
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9. Comparison of total phenol content and antioxidant activity of herbal infusions with added Stevia reabaudiana Bertoni
Abstract Antioxidant capacity (AC) was determined by the ABTS method and DPPH, and total phenol content (TPC) in dehydrated plant material, in infusions and in residues (plant material after preparing the infusion) of white, black, red, green, spearmint, stevia, lemon grass and chamomile teas to which stevia leaves were added or not added; addition of proces
Food Sci. Technol. Publicado em: 04/11/2019
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10. Use of Carbon Dots Synthesized from Citrate as a Fluorescent Probe for Quercetin Determination in Tea and Beer Samples
In this work, carbon dots (CDs) prepared by a one-step hydrothermal method were employed for the determination of quercetin in teas and beers. The fluorescence quenching of CDs was proportional to the concentration of quercetin. Under optimum experimental conditions, linear quenching was observed for quercetin in the range of 1.0 to 10 mg L-1 (F/F0 = (0.1511
J. Braz. Chem. Soc.. Publicado em: 24/10/2019
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11. Influence of preparation procedures on the phenolic content, antioxidant and antidiabetic activities of green and black teas
The influence of common tea preparation procedures (temperature, infusion time, consumption time interval and tea bag/loose-leaf) and the type of water used, on the total phenolic content (TPC), the radical scavenging activity and the α-glucosidase inhibitory activity were assessed. Higher TPC and antioxidant activity were obtained when using lower minerali
Braz. J. Pharm. Sci.. Publicado em: 23/09/2019
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12. Toxicological properties of an aqueous extract of Aristolochia triangularis leaves, using the brine shrimp lethality and Allium cepa bioassays
RESUMO: O extrato aquoso de folhas de Aristolochia triangularis mostrou atividade sobre larvas de Artemia salina, com um DL50 de 370,6 µg/mL. Em experimentos com sementes de Allium cepa, o extrato provocou uma redução de 51,26% no índice de germinação, inibiu o crescimento radicular médio e foi citotóxico nas concentrações de 668 e 2.000 µg/mL. S
Cienc. Rural. Publicado em: 15/08/2019