Brands Of Green Tea Research Articles

A sensor array based on a nanozyme with polyphenol oxidase activity for the identification of tea polyphenols and Chinese green tea

Green tea is popular among consumers because of its high nutritional value and unique flavor. There is often a strong correlation among the type of tea, its quality level and the price. Therefore, the rapid identification of tea types and the judgment of tea quality grades are particularly important. In this work, a novel sensor array based on nanozyme with polyphenol oxidase (PPO) activity is proposed for the identification of tea polyphenols (TPs) and Chinese green tea. The absorption spectra changes of the nanozyme and its substrate in the presence of different TPs were first investigated. The feature spectra were scientifically selected using genetic algorithm (GA), and then a sensor array with 15 sensing units (5 wavelengths × 3 time) was constructed. Combined with the support vector machine (SVM) discriminative model, the discriminative rate of this sensor array was 100% for different concentrations of typical TPs in Chinese green tea with a detection limit of 5 μM. In addition, the identification of different concentrations of the same tea polyphenols and mixed tea polyphenols have also been achieved. Based on the above study, we further developed a facile and efficient new method for the category differentiation and adulteration identification of green tea, and the accuracy of this array was 96.88% and 100% for eight types of green teas and different adulteration ratios of Biluochun, respectively. This work has significance for the rapid discrimination of green tea brands and adulteration.

Hot water infusion technique to prepare antioxidant-rich beverage with pomegranate peel: Formulation, nutritional study and cost analysis

This study aimed to utilize the pomegranate by-product for the formulation of antioxidant-rich beverage by the hot water infusion technique. The beverage was prepared with twelve variations of pomegranate peel powder at three different levels i.e. 2, 3 and 4 g along with combinations of three different spices (cardamom, ginger and cinnamon). Organoleptic properties of all the infusion formulations were examined, and it was noticed that the acceptable rate with no significant difference were there amongst the three levels of the pomegranate peel powder. Whereas, significant (p ≤ 0.05) difference in the acceptability of infusions with different spice powders was observed. However, cardamom spiced infusion was most liked by the panellist followed by ginger and cinnamon. Additionally, the antioxidant activity of the beverage was compared with four commercial brands of green teas. Peel infusion's DPPH● and FRAP values were found to be greater than those of the green tea brands by 18 % and 11 %, respectively. Cost estimation for the most accepted flavour, was also done.

Content of Some Elements in the Bestselling Brands of Green Tea on the Iranian market

Content of Some Elements in the Bestselling Brands of Green Tea on the Iranian market

Assessments of Cu, Zn, Pb, Cd, Fe and Mg in some brands of green tea in Baghdad markets

This study aimed to measure the concentration of the elements: Cu, Zn, Pb, Cd, Fe and Mg, as well as the percentage of fat, ash, protein and moisture of ten sample of green tea that collected from Baghdad city markets. The results showed the highest value of ash and moisture (6.10, 4.55) in chamain, Dilmah, while lowest value (5.12, 3.21) in Lipton, Mahmood green tea respectively. Dilmah and Alghazalaen show the highest value of fat, protein (2.80, 15.03) respectively, the lowest percent of fat and protein was abserved in Mahmood, Alwazah green tea, respectively. The levels of elements in this study were investigated by using atomic absorption spectrophotometry. All elements concentration was below the permissible limits of the Iraqi standard specifications for tea.

Characterization and Analysis of Polyphenols in Green and Black Tea Brands Available in Commercial Market of Pakistan

In present study, the quality of commercial brands of green and black tea available in Pakistan was analyzed on the basis of phenolic contents. Total phenolic content was analyzed through spectrophotometric measurement using the ferrous Tartrate method. Individual catechins along with gallic acid and caffeine were determined using HPLC-UV. TPC of green tea was found to be higher than black tea. Among green tea brands, Lipton Clear Green showed higher TPC than Tapal Gulbahar. Both green and black tea polyphenols showed higher solubility in the aqueous acetone (50%, v/v) compared towater. (-)-EGCG was detected as the most abundant catechins in all green and black tea samples. Theaflavin content of Lipton Yellow Label and Vital was significantly higher than Tapal Family Mixture and Tetley. Based on catechins and theaflavins content, Lipton Clear Green, Lipton Yellow Label, and Vital Tea were considered to be of higher quality than other brands.

Quantitative Analysis of Caffeine in the Green Tea, Black Tea and Soft Drink Using UV-Visible Spectrophotometer

Objective -To determine the content of caffeine in the beverages like green tea, black tea, and soft drink which are commercially available in the local market of Hapur with the help of a UV Visible spectrophotometer. Method- To find out the content of caffeine, six different brands of green tea, black tea, and soft drink were purchased from the local market in Hapur. The caffeine was extracted from them using chloroform as an extractant and assessed qualitatively and quantitatively with the help of a UV Visible spectrophotometer. The maximum absorbance of caffeine in chloroform occurs at 273 nm. The standard solutions of caffeine from the range 2-30 ppm were prepared in the chloroform, show the linearity with the correlation coefficient of 0.99. From the calibration curve, the concentration of caffeine was determined in various brands. It is observed that black tea contains the maximum caffeine content followed by green tea and soft drinks. Findings- In this study the maximum caffeine content find out was (45.6 mg/g) in the Nice black tea sample and the minimum (0.161 mg/ml) in Pepsi soft drink sample. Novelty-The caffeine content reported here is higher than that of previous studies may be due to the modified approach [treatment temperature (90-1000C) and longer brewing time (05 minutes) in this study. The use of the UV-Visible spectrophotometer is also an alternative to the HPLC technique, thereby the working cost could be brought down. Keywords: Caffeine; brewing time; beverages; UV visible spectrophotometer; extraction

Bioactive compounds and antioxidant activity of black and green tea available in Bangladesh

People in Bangladesh are traditionally used to consume mainly black tea. However, some tea manufacturing companies are now producing green tea, though in a small scale. To create new knowledge as well as awareness about the consumption of green tea, the present study was carried out to compare the black and green tea available in Bangladesh based on their bioactive compounds and antioxidant activity. A total of eight brands of black tea and two brands of green tea were bought from the supermarkets. Total phenolics, total tannin, total flavonoids, and caffeine content were measured as bioactive compounds, and antioxidant activity was evaluated by using two different methods such as DPPH (1,1- diphenyl-2-picrylhydrazyl) radical-scavenging activity and ABTS+ radical scavenging activity of methanol extracts of black and green tea. Every bioactive compound in black and green tea was found to be significantly different (P < 0.05). The total phenolic content, on average, was measured at 242.46 mg GAE/g dry extract and 763.41 mg GAE/ g dry extract in black and green tea, respectively. Black tea contained 6.47 mg TAE/g dry extract tannin, whereas green tea had much more tannin content, 14.51 mg TAE/g dry extract, which is more than double in amount. On the other hand, the total flavonoid content was almost double in black tea (61.82 mg QE/g dry extract) compared to green tea (31.85 mg QE/g dry extract). Antioxidant activities were determined at different concentrations of tea samples. At every concentration, green tea presented higher ABTS+ and DPPH radical scavenging activity than black tea. The highest percentage of inhibition was observed at 20 ppm both in black and green tea, finding 98.50 % and 99.07 % inhibition, respectively. Overall, significantly (P < 0.05) higher amount of phenolic compounds as well as antioxidant activity were observed in green tea.

Extraction and Estimation of Different Active Constituents present in the different brands of Green Tea by using Analytical Methods

Green tea (camellia sinensis. L) is one of the most popular highly used in nutritional supplement in the world. Ethanol and water were used as a solvent to extract active constituents from different brand of green tea like Lipton, Tetley, and Ecovalley natural green tea. The active constituents of green tea can be determined by analytical instruments like IR spectrophotometer used to know functional groups and TLC technique is used to know purity and no of different constituents of different brands of green tea. The absorbances can be determined by Colorimetry and UV spectroscopy, The DSC can be used to know the melting point of different constituents of different brands of green tea. The antioxidants present in the different brands of green tea estimated by using DPPH method. Predict the Immune booster activity of-(-) epigallo catechin gallate (EGCG) with target protein 3NG5 by docking study using the software swiss docking. By the above analytical methods, Ethanolic extract shows high percentage of yield than hot water extraction. Lipton green tea brand shows more active constituents compared to other brands of green tea.

Proximate, Phytochemical and Antioxidant Mineral Compositions of Four Different Brands of Tea

The comparative studies of the proximate, phytochemical and antioxidant mineral compositions of four different brands of green tea were investigated. The four different brands, Tianshi®, Qualitea®, Slimfit®, and Xiang® were purchased from a supermarket in Ihiala Local Government Area of Anambra State, Nigeria. The samples were pulverized and stored in an airtight container prior to analysis. The proximate composition was analysed using AOAC method while phytochemical compositions of the green teas were investigated using standard methods. The result of the study indicated that the moisture content (15.80±0.01%) and protein content (1.05±0.00%) of Qualitea® was significantly higher (P<0.05) compared to Slimfit and Xiang tea while the fibre content of Xiang tea (80.35±0.03%) was significantly higher (P<0.05) than other tea studied. The phytochemical study showed the presence of flavonoids, tannins, alkaloids, saponins and cardiac glycosides in all the teas studied. However, Qualitea® contains the highest amount of phytochemicals when compared to the other brands of tea investigated. Data obtained from the antioxidant mineral study showed that the four brands of the tea are good sources of antioxidant minerals such as Fe, Zn, Cu, Mn and Se. It is therefore recommended that tea be included in our menu because of their nutritive and health benefits.

Comparative Studies on Total Polyphenols, Flavanoids and Antioxidant Potential of some Marketed brands of packed Green Tea

Many phenol compoundspresentin the green tea havea wide range of biological effects which improves many health issues due to its Antioxidant property. Our objectives are to conduct the comparative studies among some leading brands of green tea by ISO 14502 procedures to check the quality of the green tea. And the differences in polyphenol Content and Antioxidant Potential followed by specified preparation method in product package for the consumers. As per ISO 14502 procedure guidelines to tea manufacturers QC passing it should not less than 20gm/100gm Gallic acid Equivalent, the results showed that TETLEY brand contains GAE 21.9±1.48 gm/100gm, in case of LIPTON brand contains GAE 28.3±1.22gm/100gm and AVT brand contains GAE 17.67 ±0.12 gm/100gm it seems only LIPTON brand passed the QC. But in product package specified preparation method the results showed that TETLEY brand contains GAE 0.266±0.035gm/d L and QE 0.388±0.049gm/d L, LIPTON brand contains GAE 0.094±0.01gm./d L and QE 0.107±0.008gm/d Land AVT brand contains GAE 0.221±0.002gm/d L and QE 0.296±0.021gm/d L seems 65% to 75% content is less in case of LIPTON. In vitro antioxidant activity studies revealed that, one teaspoon (2.961g.approx) of TETLEY brand, one teaspoon (2.682g.approx) AVT brand and halfa teaspoon (1.623g. approx.) suggested by LIPTON brand possessed the IC 50 values 1.62, 1.55 and 2.5 respectively, if the IC50 value is lesser which indicates more the antioxidant capacity. The obtained results indicates that half a teaspoon of Lipton possess lesser antioxidant potential when compared to other brands. So considering from the results we may conclude that consumers can prepare the green tea as per their requirements not to stick on product specified method of preparation. In future this study can be extended to know the ground reality with subjective to human consumptions to know the actual amount of content is required to get maximum benefits for antioxidants potentiality.

On-line high-performance liquid chromatography coupled with biochemical detection method for screening of α-glucosidase inhibitors in green tea.

An on-line high-performance liquid chromatography-biochemical detection (HPLC-BCD) method, in which compounds separated by HPLC were on-line reacted with enzyme and substrate solutions delivered by flow injection and the enzyme inhibition signal was collected by UV detection, was developed to rapidly screen α-glucosidase inhibitors from green tea extracts in this study. The chromatographic fingerprints and enzyme inhibition profiles of the different brands of green tea could be simultaneously detected by the on-line HPLC-BCD method. Enzyme inhibition profiles were detected by the UV detector at 415 nm based on the reaction of α-glucosidase and p-nitrophenyl α-d-glucopyranoside (PNPG). PNPG (1.25 mm), α-glucosidase (0.4 U/mL) and the flow rate 0.07 mL/min were applied as optimized parameters to detect α-glucosidase inhibitors in green tea. Four components in green tea showed α-glucosidase inhibition action and three of them were identified as HHDP-galloyl glucose, (-)-epigallocatechin-3-gallate and (-)-epicatechin-3-gallate by HPLC-fourier-transform mass spectrometry (HPLC-FTMS). Two brands of green tea derived from Mengding and Enshi mountainous areas might be superior to the other samples in the prevention and treatment of diabetes owing to their stronger activities of enzyme inhibitors. The proposed on-line HPLC-BCD method could be used to rapidly identify the potential enzyme inhibitors in complex matrixes.

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

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

Preliminary analysis of eight brands of green tea commercially available in Kuwait

Green tea is known for its beneficial effects and content of polyphenols. However, no data is available on the composition of the brands of green tea available in the Kuwaiti market. Limited analysis of components in 8 locally available brands of green tea was carried out. The analysis included total phenol content, bioactive polyphenols (catechins), caffeine and antioxidants, as well as analysis of ascorbic acid, fatty acids and trace metals. Total phenols ranged between 6.46–40.40 mg/g dry weight (DW). (−)‐epigallocatechin gallate (EGCG) and (−)‐epicatechin (EC) contents ranged from 162–654 and 78–386 mg/g DW, respectively. Magnesium was the major metal in all brands of green tea with heavy metals, such as cadmium having variable levels (0.7–15.4 mg/kg DW). Five fatty acids (palmitic, oleic, linoleic, 11‐eicosaenoic, cis‐15‐tetracosenoic) were found in most of the brands of green tea analyzed. Ascorbic acid levels ranged from 0.650 to 0.904 mg/g DW and total antioxidants were between 2.10 and 3.25 mmole/g DW. We report that the 2 brands of green tea having the highest levels of phenols, polyphenols and antioxidants are Al‐Wazzah and Lipton. The major catechin, EGCG, was purified by preparative HPLC and assessed for anti‐diabetic activity in streptozotocin (STZ)‐induced diabetic rats during a 4 week daily treatment experiment. EGCG (100 mg orally daily) was effective in limiting weight loss and lowering blood glucose levels of diabetic rats. In addition, EGCG was effective in decreasing polydipsia and hypertension typical of diabetic rats.Support or Funding InformationThe study was supported by KU grant #SL 01/15.

COMPARATIVE STUDY OF THE ANTIOXIDANT CAPACITY IN GREEN TEA BY EXTRACTION AT DIFFERENT TEMPERATURES OF FOUR BRANDS SOLD IN COLOMBIA

BACKGROUND: Tea ( Camellia sinensis ) is the most highly consumed beverage in the world in addition to water. The most common way of preparation is steeping it in hot or cold water.(1) In Colombia, this is a recent trend and the market is growing continuously. OBJECTIVES: The goal of this study is to compare the antioxidant characteristics of green tea of four brands sold in Colombia at room and hot-temperature in relation to brewing conditions. METHODS: A set of four commercial brands of green tea (Oriental ® , Lipton ® , Hindu ® , Jaibel ® ) was 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 using a spectrophotometric method and the antioxidant capacity was determined by means of both the scavenging of (DPPH) free radical assay, and the oxygen radical absorbance capacity (ORAC) assay. Finally, a method for quantifying the catechins present in tea extracts were developed applying high performance liquid chromatography (HPLC). RESULTS: The TPC obtained was: 2.53 – 14.63 mg EAG / g sample for cold tea extract and 29.34 - 55.06 mg EAG/g sample for hot tea extract. The TFC was found to vary: 2.67 – 7.08 mg EC/ g sample for the cold tea extract and 5.43– 8.41 mg EC/ g sample for hot tea extract. A similar profile was observed for the antioxidant capacity determined by both methods: 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 behavior of the two extraction concerning the assay, starting from the best followed this order: Oriental ® > Lipton ® > Hindu ® > Jaibel ® . The chromatographic profiles showed the presence of ten compounds. CONCLUSIONS: compounds with higher antioxidant capacity in comparison to extractions at room temperature. This results confirm the fact that extraction of green tea carried out with water at hot temperature leads to the formation of infusions rich in compounds with higher antioxidant capacity in comparison to extractions at room temperature.

Estimated daily intake of phenolics and antioxidants from green tea consumption in the Korean diet

To estimate daily intake of total phenolics and flavonoids from green tea and the contribution of green tea to the antioxidant intake from the Korean diet, 24 commercial brands of green tea were selected and analyzed. Data from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 and 2011 indicate that the green tea consumption in these 2 years was 2.8 g/tea drinker/day and 2.9 g/tea drinker/day, respectively. Based on data derived from direct measurements of green tea phenolics and the dataset of the 2008 KNHANES, we estimated the daily per tea drinker phenolics intake to be 172 mg gallic acid equivalents (GAE), the total flavonoids to be 43 mg catechin equivalents (CE) and the total antioxidants to be 267 mg vitamin C equivalents (VCE; 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay) and 401 mg VCE (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) assay). In 2011, we estimated the daily per tea drinker total phenolics intake to be 246 mg GAE, the total flavonoids to be 60 mg CE and the antioxidants to be 448 mg VCE (DPPH assay) and 630 mg VCE (ABTS assay). The daily intake of total phenolics, total flavonoids and antioxidants from green tea consumption increased from 2008 to 2011.

Comparative Study of the Antioxidant Activity of Two Popular Green Tea Beverages Available in the Local Market of Saudi Arabia

Antioxidants have numerous applications due to their multiple roles in diminishing harmful effects of oxidative stress. The objective of this work was to highlight the importance of green tea by evaluating the antioxidant activity of the most popular green tea brands in Saudi Arabia, Lipton and Rabea. To our knowledge, no studies have so far been done to estimate the antioxidant activity of these brands. To determine the antioxidant activities of these two brands, 10 mg/ml of each brand was extracted and their total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, hydrogen peroxide scavenging activity, ferric reducing power and ferrous ion chelating effect were measured. The TPC of Lipton tea was 678.7 υg of gallic acid equivalents (GAE)/10mg, whereas in Rabea tea, the TPC was 647.1 υg GAE/10mg. The presence study indicated that there were no significant differences in total phenolic contents and the percentage inhibition as shown in DPPH and H2O2 assays among Lipton and Rabea green teas. Moreover, it was found that all assays have exhibited high antioxidant activity in both green teas. In conclusion, our study showed evidence for evenness and stability of the antioxidant activity of the two commercial green teas available in the markets of Saudi Arabia. Continued researches are needed to further the current knowledge on the health-promoting effects of this popular beverage using different supplements by different mechanisms.

Polifenóis totais e flavonoides em amostras de chá verde (Camellia sinensis L.) de diferentes marcas comercializadas na cidade de Salvador-BA

RESUMO Camellia sinensis é amplamente conhecida por seus efeitos benéficos à saúde humana. Dentre as diversas formas de processamento desta erva, o chá verde e chá preto são os mais populares. Neste trabalho objetivou-se avaliar os teores de fenólicos totais e flavonoides em amostras de 25 diferentes marcas disponíveis à venda em farmácias e supermercados de Salvador-Ba. Os resultados obtidos apresentaram diferenças significativas na concentração dos compostos fenólicos entre as marcas de chá verde estudadas. No estudo também ficou comprovado que, no preparo do chá verde, as amostras obtidas por infusão aquosa com agitação mecânica apresentaram maiores teores de polifenóis e flavonoides em relação àquelas que não foram submetidas à agitação.

Contribution of temporal dominance of sensations method to the sensory description of taste properties of commercial green tea brands

This paper aims to investigate the most dominant taste attributes of green tea samples in panelists perception over time. In order to assess the samples, a brand new method of sensory evaluation called „Temporal Dominance of Sensations“ was used. The five commercial green tea brands were evaluated by eight trained panelists (students). For each sample of green tea, curves of the dominance of each attribute over time were computed. The TDS curves provided information about the sequence of attributes that were dominant during degustation. This methodology was useful to characterize taste properties of green tea samples.

Total Polyphenols Content and Antioxidant Activity of Different Tea Commercially Produced in Nepal

This study was conducted to assess and compare the total polyphenol content (TPC), antioxidant activity of different tea varieties commercially produced in Nepal. Nine different brands of tea samples, three from each CTC, orthodox and green tea were collected from different parts of Kathmandu valley. TPC was analyzed as per folin-ciocalteu method and antioxidant activity as per DPPH (2, 2-diphenyl-1-picrylhrdrazine) free radical scavenging capacity. The TPC was found to be 4.60, 8.79, 18.20mg of phenol equivalent (PE)/gm of sample in CTC, orthodox and green tea respectively. Green tea Emerald and green tea Kanchanjunga contained the highest level of polyphenol. Antioxidant activity (for 0.36 mg of tea sample) was found to be 25.04, 43.86, and 72.39% for CTC, orthodox and green tea respectively. Moreover, some commercial brands of green tea (Emerald and Kanchanjunga) showed the highest antioxidant activity. The TPC and antioxidant activity of different commercial brands of tea were found to be positively correlated (r=0.97). J. Food Sci. Technol. Nepal, Vol. 6 (73-77), 2010 DOI: http://dx.doi.org/10.3126/jfstn.v6i0.8264

Qualidade funcional da infusão do chá verde comercial

OBJETIVO: O objetivo deste trabalho foi avaliar a qualidade de duas marcas comerciais de chá verde em sachê, e verificar o efeito do tempo de infusão, em intervalos de tempos que incluem o recomendado pelo fabricante, sobre a disponibilidade dos compostos funcionais. MÉTODOS: Por análises em cromatografia líquida ultrarrápida com detector de arranjos de díodo,foram identificadas e quantificadas a cafeína, a catequina, a epigalocatequina, a rutina e a epicatequina. RESULTADOS: A epigalotocatequina e a catequina foram encontradas em maior concentração no tempo seis minutos de infusão em água (100°C) em ambas as marcas, sendo a rutina apenas encontrada na infusão por seis minutos e em apenas uma das marcas avaliadas. A extraçãocom metanol (99,8%) aumentou significativamente o rendimento de todos os compostos avaliados. Foi observado que atividade antioxidante equivalente ao trolox do chá aumentou diretamente com o aumento do tempo de infusão, no entanto, para os extratos obtidos em metanol, a atividade antioxidante foi menor que todos os outros tratamentos, havendo diferença significativa (p<0,05). CONCLUSÃO: As análises químicas de umidade, cinzas e cinzas insolúveis em ácido clorídrico revelaram que as duas marcas avaliadas estão em conformidade com a legislação para esses parâmetros, bem como com relação à presença de sujidades e materiais estranhos, revelados na microscopia.