scholarly journals Total Polyphenol, Rehydration Ratio, and Liquor Color of Different Grade Green Tea

2020 ◽  
Vol 3 (2) ◽  
pp. 159-169
Author(s):  
M Iqbal Prawira-Atmaja ◽  
Beauty Azhary ◽  
Sugeng Harianto ◽  
Hilman Maulana ◽  
Shabri Shabri ◽  
...  
Keyword(s):  
Green Tea ◽  
Alcoholic Beverage ◽  
Black Tea ◽  
Enzymatic Oxidation ◽  
Rehydration Ratio ◽  
Total Polyphenols ◽  
Potential Health ◽  
Total Polyphenol ◽  
Practice Gap

Tea is a non-alcoholic beverage that is widely consumed after water with potential health benefits. In general, tea processing divided into three types, non-enzymatic oxidation process (green tea), semi-oxidation (oolong tea), and with enzymatic oxidation (black tea). The sorting and grading is a stage in controlling the quality of green tea. This study aims to determine the characteristics of different grades of green tea on the total polyphenols, liquor color, and rehydration ratio. The results showed that the pekoe/pecco grade had the highest total polyphenol and rehydration ratio compared to other grades. Pekoe grade has a greenish yellow  and brighter liquor color. Application of good agriculture practice (GAP) and plucking of fresh tea leaves should be considered to obtain more grade pekoe in the green tea processing.

scholarly journals PENGARUH UMUR DAUN TEH DAN WAKTU OKSIDASI ENZIMATIS TERHADAP KANDUNGAN TOTAL FLAVONOID PADA TEH HITAM (Camellia sinesis)

2021 ◽  
Vol 10 (1) ◽  
pp. 41
Author(s):  
Jennifer Larisa Liem ◽  
Maria Marina Herawati
Keyword(s):  
Black Tea ◽  
Total Flavonoid ◽  
Enzymatic Oxidation ◽  
Average Level ◽  
Flavonoid Compound ◽  
Total Flavonoids ◽  
Tea Leaves ◽  
Time Treatment ◽  
Oxidation Stage

Flavonoid compound is an important compound of tea products. However, the flavonoid level content in black tea is lowest than other teas. This is due to the processing of black tea which has an enzymatic oxidation stage and  the tea age leaves when picking. Young tea leaves contain higher total flavonoids than old tea leaves. With an average level of total flavonoids, the young tea leaves is 27.76% qe w / w, while for the old tea leaves 18.61% qe w / w. However, the enzymatic oxidation time treatment did not affect the total flavonoids because the process only affected the quality of black tea steeping, on it’s colour, aroma, and taste. Keywords: age of tea leaves, black tea, enzymatic oxidation, total flavonoids

scholarly journals Influence of phenolic compounds on sensory parameters of tea infusions

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S195-S198
Author(s):  
P. Košulič ◽  
J. Pokorný ◽  
Z. Panovská
Keyword(s):  
Phenolic Compounds ◽  
Green Tea ◽  
Black Tea ◽  
Total Polyphenols ◽  
Iso Standards ◽  
Tea Infusions ◽  
Sensory Parameters

A set of 9 black teas and 10 green teas were analyzed. Sensory parameters of tea infusions were correlated with the content of total polyphenols (determined after Folin and Ciocalteu) and sensory parameters (determined after ISO standards). Total polyphenols affect both the astringency and the bitterness of green tea and black tea infusions. The relations are mainly semilogarithmic, but very close to linear. Sucrose decreased the astringency by 30–40%, and the bitterness was suppressed still more.

scholarly journals Changes in Phytochemicals and Determination of Optimum Fermentation Time during Black Tea Manufacturing

2020 ◽  
Vol 12 (4) ◽  
pp. 657-664
Author(s):  
M. M. Rahman ◽  
M. M. Hossain ◽  
R. Das ◽  
I. Ahmad
Keyword(s):  
Black Tea ◽  
Quality Parameters ◽  
Biochemical Changes ◽  
Enzymatic Oxidation ◽  
Time Intervals ◽  
Fermentation Time ◽  
Tea Quality ◽  
Processing Steps

Black tea processing consists of four steps, namely withering, CTC, fermentation and drying, while cup quality made tea mostly controlled by fermentation step. This study evaluated biochemical changes at different stages of black tea processing in Bangladesh and determined the optimum fermentation time. Samples were collected from different tea processing stages to measure major phytochemicals and time intervals during fermentation to measure theaflavins and thearubigins ratio. Caffeine content was the least susceptible to processing steps. Biochemical changes started at withering, cell maceration and enzymatic oxidation started at CTC processing, thus the major reduction in the reducing sugar (20.46 to 04.95 ppm), catechin (16.88 to 7.95 ppm) and polyphenol (42.30 to 30.73 ppm) occurred here. The significant changes appeared during fermentation when polyphenol content decreased from 44.66 to 18.23 and catechin from 17.41 to 03.98 ppm due to the breakdown of these compounds to theaflavins (TF) and thearubigins (TR). The TF and TR ratio increased with fermentation time, and the highest of 1:8.4 was found at 50 min, which turned into 1:10 in the final product. The made tea quality parameters were comparable or better at fermentation time of 50 min than the quality of the black tea available in market.

scholarly journals Effect of Musts Oxygenation at Various Stages of Cider Production on Oenological Parameters, Antioxidant Activity, and Profile of Volatile Cider Compounds

Biomolecules ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 890
Author(s):  
Tomasz Tarko ◽  
Aleksandra Duda-Chodak ◽  
Paweł Sroka ◽  
Magdalena Januszek
Keyword(s):  
Antioxidant Activity ◽  
Alcoholic Beverage ◽  
Control Sample ◽  
Wine Yeast ◽  
Volatile Components ◽  
Polyphenol Content ◽  
Total Polyphenol ◽  
Wild Yeast ◽  
Yeast Strains

The micro-oxygenation of musts may affect the quality of a finished alcoholic beverage. The aim of this study was to determine the effect of micro-oxygenation at various stages of fermentation on oenological parameters, antioxidant activity, total polyphenol content, and profile of volatile cider compounds fermented with various yeast strains. Rubin cultivar must was inoculated with wine yeast, cider yeast, distillery yeast, and wild yeast strains. Some of the inoculated samples were oxygenated immediately after yeast inoculation, and some on the second and third fermentation days. The control sample was non-oxygenated must fermented in bottles. Higher extract concentration and acidity as well as lower potency were observed in cider treated with micro-oxygenation. Must oxygenation in most cases contributed to the reduction of polyphenol content and to the antioxidant activity of ciders, especially when fermented using wild yeast. The oxygenation of musts before fermentation caused an increase in the content of esters and alcohols in ciders. However, the oxygenation of musts during fermentation reduced the concentration of these volatile components. The oxygenation of musts during fermentation produced a differentiated effect on terpenoid concentration in ciders.

scholarly journals Authenticity evaluation of tea-based products

2008 ◽  
Vol 26 (No. 4) ◽  
pp. 259-267 ◽  
Author(s):  
H. Čížková ◽  
M. Voldřich ◽  
J. Mlejnecká ◽  
F. Kvasnička
Keyword(s):  
Experimental Data ◽  
Green Tea ◽  
Analytical Methods ◽  
Black Tea ◽  
Equivalent Amount ◽  
Chemical Markers ◽  
Tea Leaves ◽  
Total Polyphenols ◽  
The Mean ◽  
Tea Extract

This study proposes a method for estimating the content of tea in tea-based products. Broadly, this methodology is based on selecting chemical markers of the quality and authenticity of tea (and, therefore, of tea-based products), optimising the relevant analytical methods, and determining variations (type, origin, quality) among samples of green and black leaf teas. The contents of the selected markers (theobromine, caffeine, theanine, and total polyphenols) in tea-based products (iced teas, instant teas) were determined. Then, the dry tea content in these products, expressed as the equivalent amount of dry tea leaves, was calculated on the basis of two sets of mean data for these analytes: average literature data, and the mean experimental data obtained with our samples of leaf tea. With regards to the latter, we propose to use of the following averages for caffeine, theobromine, theanine, and polyphenols: for 100 g of black tea-based products 1.9 g, 0.13 g, 1.3 g, and 9.1 g, respectively; for 100 g of green tea-based products 1.9 g, 0.16, 1.7 g, and 14.7 g, respectively. Using this method, we found that approximately one third of the analysed samples failed to meet the tea extract levels required by German and Austrian legislations, while about 10% did not comply with the less demanding Czech legislative requirements.

scholarly journals Changes of phenolic compounds of tea leaves during Oolong tea process

2014 ◽  
Vol 17 (1) ◽  
pp. 67-75
Author(s):  
Tram Ngoc Nguyen ◽  
Oanh Ngoc Huynh ◽  
Hien Phuoc Phan
Keyword(s):  
Phenolic Compounds ◽  
Green Tea ◽  
The Other ◽  
Tea Leaves ◽  
Total Polyphenols ◽  
Oolong Tea ◽  
Other Hand ◽  
Green Tea Leaves

It was believed that provided photographs of changes of total polyphenols (TPP), tannin, theaflavins (TF), thearubigins (TR) contents and total colour liquids. Green tea leaves were going through the stages: fresh tea → withering → incubated 1 → aromatic spin 1 → incubated 2 → aromatic spin 2 →fried inactivated enzymes. Tea samples in the stages were provided by Cau Tre tea factory. Tea samples were divided into two groups: the activated and inactivated enzyme groups – microwave was applied to treated the activated enzyme one. Tea samples after the inactivation were conducted. The results showed that TPP and tannin contents generally decreased. Changes of theaflavin contents were contrast to tannin contents. On the other hand, theaflavin and thearubigin are the major polyphenols that determine on the quality of Oolong tea.

scholarly journals Effects of Coffee and Tea Consumption on Glucose Metabolism: A Systematic Review and Network Meta-Analysis

Nutrients ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 48 ◽  
Author(s):  
Yoshinobu Kondo ◽  
Atsushi Goto ◽  
Hisashi Noma ◽  
Hiroyasu Iso ◽  
Kunihiko Hayashi ◽  
...  
Keyword(s):  
Systematic Review ◽  
Glucose Metabolism ◽  
Green Tea ◽  
Meta Analysis ◽  
Fasting Blood Glucose ◽  
Black Tea ◽  
Tea Consumption ◽  
Post Intervention ◽  
Quality Of Evidence

Prospective cohort studies have described an association between coffee or tea consumption and the risk of developing diabetes. However, whether coffee or tea improves glucose metabolism remains uncertain. We investigated the effect of coffee and tea on glucose metabolism by conducting a systematic review and meta-analysis of randomized controlled trials. Electronic databases were searched for articles published up 19 February 2017. The primary endpoint was the mean difference in post-intervention fasting blood glucose (FBG) levels between the groups. Of 892 citations screened, 27 studies (1898 participants) were included in our meta-analysis. A network meta-analysis suggested that green tea, but not caffeinated/decaffeinated coffee or black tea, may reduce FBG levels, compared with placebo/water (−2.10 mg/dL; 95% confidence interval (CI), −3.96 to −0.24 mg/dL; p = 0.03; moderate quality of evidence). In a subgroup analysis, the effect of green tea on FBG levels was statistically significant only in studies with a mean age of < 55-years-old or Asian-based studies. The oolong tea group also showed a significant decrease in FBG, but the quality of evidence was very low. In conclusion, green tea consumption might decrease FBG levels, especially in < 55-year-olds or Asian-based populations.

scholarly journals Quality Green Tea (Camellia sinensis L.) Clones Marked through Novel Traits

Beverages ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 63
Author(s):  
Pradeep Kumar Patel ◽  
Dapeng Zhang ◽  
Devajit Borthakur ◽  
Monpi Hazarika ◽  
Pulakesh Boruah ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Green Tea ◽  
Net Photosynthesis ◽  
Black Tea ◽  
Carboxylation Efficiency ◽  
First Flush ◽  
Total Polyphenol ◽  
Novel Traits ◽  
Use Efficiency ◽  
And Cluster Analysis

Tea clones and seed varieties released from Tocklai Tea Research Institutes are suitable primarily for manufacturing black tea (CTC/orthodox) while green tea manufactured from these clones are poor in quality. This led to identifying germplasm suitable for manufacturing green tea of high quality. Physiological parameters on net photosynthesis, transpiration, stomatal conductance, water-use efficiency, leaf temperature, and carboxylation efficiency of six selected germplasm (DH 1 and 2, DH 3 and 4, DH 5 and 6, DL 13, DL 25, and DL 39) were measured in first flush, second flush, rain flush, and autumn flush. Seasonal Yield, biochemical (L-theanine to total polyphenol ratio), and taster’s score were compared among seasons. Two protocols were used for green tea manufacturing, i.e., roasting and steaming. Significant differences in net photosynthesis (pn), stomatal conductance (gs), carboxylation efficiency (ci/ca), and yield were observed between flushes. Among the six test clones, the L-theanine to total polyphenol ratio found was highest in DH 5 and 6 in the roasting method. Structural and cluster analysis revealed that the DH clones genotypically occupied the same position as that of the popular green tea clone Longjing 43 of China and Yabukita of Japan, indicating suitability of these germplasm to develop new green tea clones. Clones DH 5 and 6 are suitable for green tea manufacturing and they can be released to the industry as new green tea clones. As far as manufacturing protocol is concerned, the roasting method of tea manufacturing was found superior over steaming.

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

2013 ◽  
Vol 6 ◽  
pp. 73-79
Author(s):  
Rojeena Shrestha ◽  
Jiwan Pravan Lama ◽  
Kshitij Shrestha
Keyword(s):  
Antioxidant Activity ◽  
Green Tea ◽  
Radical Scavenging ◽  
Kathmandu Valley ◽  
Polyphenol Content ◽  
Total Polyphenols ◽  
Total Polyphenol ◽  
Radical Scavenging Capacity ◽  
Scavenging Capacity ◽  
Different Parts

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

scholarly journals Effects of Foliar Spray Application of Selected Micronutrients on the Quality of Bush Tea

HortScience ◽  
2016 ◽  
Vol 51 (7) ◽  
pp. 873-879 ◽  
Author(s):  
Maedza V. Khathutshelo ◽  
Nkomo Mpumelelo ◽  
Ngezimana Wonder ◽  
Mudau N. Fhatuwani
Keyword(s):  
Foliar Application ◽  
Block Design ◽  
Foliar Spray ◽  
Total Flavonoids ◽  
Spray Application ◽  
Total Polyphenols ◽  
Total Polyphenol ◽  
Total Antioxidant ◽  
Quadratic Response

Bush tea (Athrixia phylicoides DC.) is a herbal beverage and medicinal plant indigenous to South Africa. The aim of the study was to provide the baseline for foliar spray application of micronutrients to enhance the quality of bush tea. A trial was conducted to determine the effect of micronutrients on the quality of bush tea. Four separate trials for boron (B), iron (Fe), zinc (Zn), and copper (Cu) were laid out in a completely randomized block design. Treatments consisted of an unsprayed control and single foliar sprays of B, Fe, Zn, and Cu, with 10 replicates. The levels of each element were unsprayed control, 50 mL·L−1, 100 mL·L−1, and 150 mL·L−1. Parameters recorded were leaf tissue B, Fe, Zn, and Cu, and total polyphenol, total antioxidant, total flavonoids, and total tannin contents. Results from this study demonstrated that foliar application of B did not induce significant response in terms of total polyphenol content after B application. There was a quadratic response for total flavonoids (167 mg·g−1), with most of the total flavonoids reaching maximum at 100 mL·L−1. Foliar application of Fe exhibited a quadratic response, with most of the total polyphenols (45.1 mg·g−1) reaching maximum at 100 mL·L−1. All treatments showed a linear response for total antioxidant, total flavonoids, and total tannin contents. Treatments elicited a quadratic response for total polyphenols (70.6 mg·g−1), total antioxidants (78.3 mg·g−1), total flavonoids (148.9 mg·g−1), and total tannin contents (78.3 mg·g−1) after foliar Zn application, reaching maximum at 100 mL·L−1. Foliar application of essential elements in bush tea led to a significant increase in the Zn, Fe, Cu, and B content; application at 100 mL·L−1 is recommended for improved chemical composition of bush tea. A further trial with treatment combinations is required to determine chemical responses of bush tea.

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