Study the Effect of Far infrared-Withering on Black Tea Manufacturing
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Date
2018
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Journal ISSN
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Withering is the foundation step of black tea manufacturing which directly influences
the quality and the cup characteristics of the made tea. This stage consumes 49% of
the total electricity required for the production process and use of dendro thermal
power releases CO2 to the environment causing environmental pollution. Far infrared
(FIR) withering may be a good alternative to overcome these problems. Therefore,
this study was conducted to identify the essentials for developing a withering trough
using Far-infrared as the heating source for black tea production and to analyze its
performances. Plucked tea leaves with an initial moisture content of 43±1% were
withered using Far-infrared panels, by changing the treatment combination of Farinfrared power (650, 1300 and 1950 W), exposure times (4 hr, 4.15 hr and 4.30 hr)
and the leaf weight (400 kg, 425 kg and 450 kg). Temperature and the relative
humidity of plenum chamber and withered leaves were measured using DHT11
sensors to maintain the conditions uniformly throughout the study. The samples were
dried and Theaflavins (TF) Thearubigins (TR) ratio was measured and organoleptic
parameters such as aroma, flavor and colour were tested. It was found that there is a
significant interaction effect of Far-infrared power, exposure time and leaf weight on
"Theaflavins/Thearubigins" ratio and organoleptic properties (p<0.05). The optimum
combination of Far-infrared power, exposure time and leaf weight were 1950 W, 4.30
hours and 400 kg, respectively based on "Theaflavin/Thearubigins "(1 :10), high score
for organoleptic properties and low energy consumption. Therefore, it can be
concluded that FIR withering has high potential in black tea manufacturing. Further
studies are needed to improve the precision of the prototype to develop it as an
industrial level withering trough.
Keywords: Black tea manufacturing, Far- infrared withering, Sensory evaluation, Theaflavins,
Thearubigins
Description
Keywords
Tea Technology, Agriculture