Determinación De Compuestos Fenólicos Totales y Evaluación De La Actividad Antioxidante De Té Verde Comercial y Artesanal Comercializados en Maracay, Venezuela (original) (raw)
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Journal of food and nutrition research
The aim of this study was evaluation of individual phenolic compounds and antioxidant activity of commercially consumed black, green, fruit and herbal tea infusions in Serbia in order to characterize the quantity and quality of teas. The most abundant compound was gallic acid, followed by caffeic acid, rutin, (+)-catechin and (-)-epicatechin. The main procyanidin was procyanidin B1. The antioxidant activity was measured using five in vitro methods: determination of 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity (DPPH), 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) radical cation-scavenging activity (ABTS), ferric reducing antioxidant power (FRAP), reduction power (RP) Fe(III) to Fe(II) and cyclic voltammetry (CV). Obtained results of FRAP and of the Fe(III)/Fe(III) method correlated strongly with the total phenolics content (R 2 = 0.92246, R 2 = 0.88084, p < 0.0001). Antioxidant power of green tea and bearberry tea was considerably higher than that of black tea. Raspberry and cherry showed the highest antioxidant power among fruit tea infusions. Contribution of phenolic compounds to tea antioxidant activity was also quantified in this study. Stepwise linear regression demonstrated that quantification of different phenolic compounds responsible for tea antioxidant activity was dependent on the method used. Gallic acid, caffeic acid (+)-catechin, (-)-epicatechin, (-)-epigallocatechin, procyanidin B1, procyanidin B2 together made up 43.6-99.9% of the antioxidant activity of tea.
The analysis of quality and antioxidant activity of green tea extracts
The aim of the research was to analyze the composition of biologically active compounds, to determine the correlation between the concentration of biologically active compounds and antioxidant activity, the dependence of extractive compounds on the extraction time, the quality of different tea preparation forms (daily tea, infusions, decoctions) of those teas found in Lithuanian market. Four specimens of green tea from different regions of the world have been chosen as the object of analysis. Quality criteria's have been analyzed by using gravimetric and spectrophotometric methods. Detailed analysis has been performed using high performance liquid chromatography (HPLC) technique. With reference to analysis results it can be stated that in the aspect of relation to antioxidant activity/phenolic compounds, the teas with highest numbers in these dimensions were those from China region. The least numbers in antioxidant activity, dry residue and phenolic compounds were of teas from S...
Beverages, 2022
Tea contains about 230 chemical bioactive compounds, of which polyphenols represent the most considerable fraction (30% of total dry weight). These compounds have relevant nutritional and pharmacological effects on human health, exerting antioxidant activities against oxidative stress-induced damage. The industrial processes applied in tea production can lead to qualitative and quantitative changes in the phenolic content and composition and in antioxidant properties, thus influencing their potential biological activities. Meanwhile, the procedure for tea preparation may influence the quantity of the extracted phenolic compounds. In this study, the effects of different infusion parameters, such as the water type used for infusion (tap water, distilled water, and natural mineral water), time (3, 5, and 10 min), temperature (T = 80 °C and 100 °C), and pH (ranged between 3 and 9) were considered. The optimal infusion variables resulting from the study were obtained by extracting phenol...
Revista Vitae
Background: Tea (Camellia sinensis) is the most highly consumed beverage in the world in addition to water. The most common way of preparation is by immersing the tea bag in hot or cold water. In Colombia, it is a recent trend and the market is growing continuously. Objectives: The objective of this study is to compare the antioxidant characteristics of four brands of green tea sold in Colombia at room and hot-temperature in relation to the preparation conditions. Methods: Four commercial brands of green tea (Oriental ® , Lipton ® , Hindú ® , Jaibel ®) were used in an aqueous extraction at two temperatures: Cold tea extract (25°C) and hot tea extract (80°C). Total polyphenol concentration (TPC) was determined by Folin-Ciocalteu method; Total flavonoid content (TFC) was determined by spectrophotometric method and the antioxidant capacity was determined by two methods: DPPH radical capture assay, and the oxygen radical absorbance capacity (ORAC) assay. Finally, a method to quantify the catechins of the tea extracts, high performance liquid chromatography (HPLC) was applied. Results: The TPC vary between: 2.53-14.63 mg GAE/ g sample for cold tea extract and 29.34-55.06 mg GAE/g sample for hot tea extract. The TFC vary between: 2.67-7.08 mg CE/g per sample for the cold tea extract and 5.43-8.41 mg CE/ g sample for hot tea extract. A similar profile assays: for cold tea extract: 22.36-41.29 mg TE /g sample for DPPH and 22.95-46.25 mg TE/g sample for ORAC. Similarly, for hot tea extract the following ranges were: 38.50-110.01 mg TE/g sample for DPPH and 23.40-113.60 mg TE/g sample for ORAC. In general, the values obtained in each assay for each brand were as follows: Oriental ® > Lipton ® > Hindú ® > Jaibel ®. The chromatographic profiles showed the presence of ten compounds. Conclusions: These results confirm that the aqueous extraction of green tea at 80°C leads to the formation of infusions made up of compounds with higher antioxidant capacity in comparison with extractions at room temperature.
A Comparison of Selected Phytochemical and Antioxidant Potential of Two Tea Beverages
Food and Nutrition Sciences, 2017
Herbal teas have been used as medicinal aids for centuries to treat a myriad of illnesses and have also been suggested to function in chemoprevention. Having numerous phytochemicals, the purported health benefits of herbal teas may be due to their antioxidant potential. Herbal tea blends infused with spices are increasing in popularity in U.S., and preliminary studies suggest the synergistic effects of combining herbal teas and spices. Some teas that are increasing in popularity include raspberry leaf, strawberry leaf, and hibiscus. The objectives of this study were to determine the antioxidant capacity of tea beverages (herbal (HT) (functional yogurt-based beverage-new product) and Chai (CT) (store bought) and to determine consumer preferences of tea beverages (HT and CT). Total phenolic content (TPC), total flavonoid content (TFC), free radical scavenging activity by 1,1-diphenyl-2-picryhydrazyl (DPPH), trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP) were evaluated in methanolic and aqueous beverage extracts. A functional yogurt-based beverage (HT) was developed and sensory analysis was also conducted using a 5-point hedonic scale comparing consumer preference of HT or CT beverages. The highest phenolic content was observed in CT aqueous extracts (AQ) (500 mg GAE/g), all other extracts had significantly (P ≤ 0.05) lower phenolic content. CTAQ had significantly (P ≤ 0.05) higher flavonoid content compared to all other extracts (1.7 mg CAE/g). The highest DPPH radical scavenging activity was observed in HT methanolic extracts (ME) (44.48% inhibition). The lowest DPPH radical scavenging was observed in HTAQ (21.88% inhibition). Approximately 61% of sensory panelists gave the yogurt-based developed product a rank of 4 or greater (on a 5-point hedonic scale) with 41% of panelists preferring the HT beverage over CT beverage. The results of this study suggest that a combination of herbal teas and spices may benefit consumers by improving their antioxidant status and may have potential as a functional-beverage.
Ciência e Tecnologia de Alimentos, 2010
Os benefícios de saúde atribuídos ao chá verde e suas catequinas têm levado a um grande aumento de produtos comerciais à base de chá verde no mercado. Os objetivos deste trabalho foram analisar e comparar estes produtos em relação ao conteúdo de fenólicos totais e capacidade antioxidante in vitro, incluindo produtos na forma de sachês, folhas desidratadas e bebidas prontas. O conteúdo de fenólicos totais em 200 mL (1 xícara) dos diferentes chás variou de 90 a 341 mg equivalentes de catequina, e o maior e o menor valor foram apresentados pelas bebidas prontas. As infusões preparadas a partir dos sachês tiveram conteúdos variando de 96 a 201 mg.200 mL-1 , e não foram encontradas diferenças significativas entre os lotes. Nos ensaios de sequestro do radical DPPH e ORAC (Oxygen Radical Absorbing Capacity), houve ampla variação dos resultados entre as diferentes preparações de chás, de 23 a 131 mmoles equivalentes de Trolox (ET).200 mL-1 (DPPH), e de 1,2 a 5,1 mmoles ET.200 mL-1 (ORAC), e novamente não houve diferenças entre as infusões e/ou bebidas comerciais prontas. Entretanto, a capacidade antioxidante das bebidas prontas para consumo é parcialmente devido à presença de outros compostos não fenólicos como o ácido ascórbico.
Screening of the antioxidant properties and polyphenol composition of aromatised green tea infusions
Journal of the science of food and agriculture, 2012
BACKGROUND: Aromatised green teas are widely sold and popular owing to their fragrance. In this study the antioxidant activity of six commercial green tea infusions was assessed by three complementary assays. RESULTS: In order to evaluate the tea infusions as antioxidant sources, their phenolic content (Folin-Ciocalteu assay), cupric ion-reducing antioxidant capacity (CUPRAC) and 2,2-diphenyl-1-picryhydrazyl (DPPH) radical-scavenging ability were determined. Their content of polyphenols was also determined by high-performance liquid chromatography/mass spectrometry (HPLC/MS) in negative electrospray ionisation mode. Some teas with citrus aroma, besides having a relatively high content of catechins, also contain other phenolic compounds such as naringin and hesperidin. The three assays used to evaluate the antioxidant capacity of the tea infusions gave different rank orders. Therefore an antioxidant index was calculated for better correlation of the results, and its highest value was...
Comparative study of antioxidant potential of tea with and without additives
Indian journal of physiology and pharmacology, 2000
Oxidative damage is one of the many mechanism leading to chronic diseases. Therefore interest is growing in the protection afforded by antioxidant nutrients against free radical reactions. More recently, the attention has shifted to polyphenols. Polyphenols are secondary plant metabolites occurring widely in plant food. They possess outstanding antioxidant properties, suggesting a possible protective role in man. Tea (Camellia sinensis) is a widely consumed beverage throughout the world containing polyphenols more than 35% of its dry weight. In the present work we have investigated the effect of tea without milk, tea with milk and lemon tea on the serum lipid peroxidation level (as a parameter of free radical generation). The results show that there were significant decrease in serum lipid peroxidation (Malonaldehyde) level half hour after ingestion of lemon tea and tea without milk which tends to normalize with increase in time. This decrease is much significant in case of lemon te...
Determination of Phenolic Components and Antioxidant Activity of Some Egyptian Tea Samples
Objective: Tea is the most widely consumed beverage in the world. Green tea (Camellia sinensis) is a good source of bioactive compounds and it is gaining interest due to its health benefits. The present study was conducted to determine the total polyphenols and total flavonoid content as well as the antioxidant activity of ethanolic extracts from different Egyptian tea samples. Methods: The determination process carried out using standard spectrophotometric methods and quantified various phenolic and flavonoid compounds by using high performance liquid chromatography (HPLC) method. The comparison was also made between Egyptian tea samples and commonly tea samples in the markets. Results: Results from this study showed that Egyptian green tea showed a significant higher values of total phenol and flavonoid, contents. The same trend was also observed in antioxidant activity as assessed using DPPH (2, 2-diphenyl-1-picrylhydrazyl) free radical scavenging assay. It revealed that the total antioxidant activity could be due to its total phenol content. Conclusion: The study concludes that Egyptian green tea offers higher amount of antioxidant properties.