Changes in the quality parameters of clonal black tea due to fermentation time

1994 ◽  
Vol 64 (3) ◽  
pp. 319-326 ◽  
Author(s):  
Philip O Owuor ◽  
John E Orchard ◽  
Ian J McDowell
Keyword(s):  
Black Tea ◽  
Quality Parameters ◽  
Fermentation Time

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.

Effect of Fermentation Time and Vegetable Concentrate Addition on Quality Parameters of Organic Botifarra Catalana, a Cured–Cooked Sausage

2012 ◽  
Vol 60 (27) ◽  
pp. 6882-6890 ◽  
Author(s):  
Núria Magrinyà ◽  
Ricard Bou ◽  
Núria Rius ◽  
Rafael Codony ◽  
Francesc Guardiola
Keyword(s):  
Quality Parameters ◽  
Fermentation Time

scholarly journals Electronic Nose Technologies in Monitoring Black Tea Manufacturing Process

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Tharaga Sharmilan ◽  
Iresha Premarathne ◽  
Indika Wanniarachchi ◽  
Sandya Kumari ◽  
Dakshika Wanniarachchi
Keyword(s):  
Neural Network ◽  
Electronic Nose ◽  
Gas Sensors ◽  
Black Tea ◽  
Quality Parameters ◽  
Polyphenolic Compounds ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Optimum Level ◽  
Fermentation Stage

“Tea” is a beverage which has a unique taste and aroma. The conventional method of tea manufacturing involves several stages. These are plucking, withering, rolling, fermentation, and finally firing. The quality parameters of tea (color, taste, and aroma) are developed during the fermentation stage where polyphenolic compounds are oxidized when exposed to air. Thus, controlling the fermentation stage will result in more consistent production of quality tea. The level of fermentation is often detected by humans as “first” and “second” noses as two distinct smell peaks appear during fermentation. The detection of the “second” aroma peak at the optimum fermentation is less consistent when decided by humans. Thus, an electronic nose is introduced to find the optimum level of fermentation detecting the variation in the aroma level. In this review, it is found that the systems developed are capable of detecting variation of the aroma level using an array of metal oxide semiconductor (MOS) gas sensors using different statistical and neural network techniques (SVD, 2-NM, MDM, PCA, SVM, RBF, SOM, PNN, and Recurrent Elman) successfully.

scholarly journals THE EFFECT OF EXTRUDED FLOUR AND FERMENTATION TIME ON SOME QUALITY PARAMETERS OF IDLI

2000 ◽  
Vol 23 (1) ◽  
pp. 15-25 ◽  
Author(s):  
KULWINDER KAUR ◽  
NARPINDER SINGH ◽  
HARDEEP SINGH
Keyword(s):  
Quality Parameters ◽  
Fermentation Time

Clonal plain back tea quality parameters responses of hard physical withered leaf to rehydration and fermentation durations

2016 ◽  
Author(s):  
P. Okinda Owuor ◽  
And Martin Obanda
Keyword(s):  
Sensory Evaluation ◽  
Polyphenol Oxidase ◽  
Oxidase Activity ◽  
Black Tea ◽  
Quality Parameters ◽  
Moisture Loss ◽  
Polyphenol Oxidase Activity ◽  
Tea Quality

Hard physical withers in tea processing result in reduced plain black tea quality parameters, but improve flavoury black tea quality. Chemical withers with minimal moisture loss improve plain black tea quality parameters. But chemical withered leaf is normally bulky and not flaccid thus reducing maceration rates. Hard physical withers reduce polyphenol oxidase activity, thereby impairing ability of the leaf to produce high amounts of plain black tea quality parameters, especially theaflavins and thearubigins. This study examined if rehydrating hard physical withered leaf could improve its fermentability and influence fermentation duration, and if such changes are cultivar dependent. Rehydrating hard physical withered leaf increased (p≤0.05) total theaflavins, thearubigins, brightness, total colour and sensory evaluation of resultant black teas. The patterns of the responses did not vary with cultivars or fermentation duration. The theaflavins and brightness declined (p≤0.05) while thearubigins and total colour increased (p≤0.05) with long fermentation durations irrespective of withering regime. Results demonstrate that problems of plain black tea quality reduction due to hard physical withers can be partially reversed by rehydration to chemical wither standard, but the withering regime does not influence when maximum plain black tea quality parameters are produced.

The determination of optimum fermentation time in Turkish black tea manufacture

1997 ◽  
Vol 60 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Mehmet Tüfekci ◽  
Saadettin Güner
Keyword(s):  
Black Tea ◽  
Fermentation Time

scholarly journals Assessing biochemical changes during standardization of fermentation time and temperature for manufacturing quality black tea

2013 ◽  
Vol 52 (4) ◽  
pp. 2387-2393 ◽  
Author(s):  
Tanmoy Samanta ◽  
Vijayakumar Cheeni ◽  
Shrilekha Das ◽  
Amrita Basu Roy ◽  
Bijoy Chandra Ghosh ◽  
...  
Keyword(s):  
Black Tea ◽  
Biochemical Changes ◽  
Fermentation Time ◽  
Manufacturing Quality

scholarly journals Optimisation of amylase and xylanase addition in dependance of white flour amylase activity

2016 ◽  
Vol 70 (6) ◽  
pp. 673-683
Author(s):  
Davor Loncar ◽  
Vladimir Filipovic ◽  
Jelena Filipovic
Keyword(s):  
Quality Parameters ◽  
Bread Quality ◽  
Grain Structure ◽  
Wheat Bread ◽  
Good Prediction ◽  
Technological Parameters ◽  
Fermentation Time ◽  
White Wheat ◽  
White Flour ◽  
Score Analysis

In this study the effect of different quantities of added amylase to white wheat flours characterized with different activities of naturally existing amylases is tested. Response surface methodology is chosen to test the effects of main applied technological parameters on bread quality responses. Independent variables are chosen to be: quantity of added amylase and bulk fermentation time, while analysed responses are: specific volume, grain structure, bulk fermentation. Bread quality responses are statistically significant, while predicted and observed responses correspond very well, which allows good prediction of bread quality parameters based on applied technological parameters and flour characteristics. Score analysis shows that optimum quantity of amylase addition regarding bread quality depends on the activity of naturally existing amylases. Optimal quantity of added xylanase in bread samples made from both flour types is 0.004%. Xylanase improved properties of white wheat bread and higher effect is experienced with flour that has more active naturally existing amylases. Addition of amylase has statistically significantly increased a* values of crust. Addition of xylanase has statistically significantly decreased values of b* in comparison to the respective bread sample with only added amylase.

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