Development of a monitoring device for fermentation stage of black tea manufacturing
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Date
2018
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
Tea is one of the popular industries around the world for its social influence. Taste,
tea colour and odor are the ways to measure the quality on the final product, but
Theaflavins/Thearubigins ratio is accepted as 1/10 for a high quality. In general
factory officers estimate the optimum fermentation time visually. However, optimum
fermentation time might depend on humidity, temperature, moisture content of
leaves, which are processing on a particular day. Thus, there is a need for a system
independent from human decision. An electronic device was developed, in order to
determine the optimum fermentation time for the black tea. A set of sensors such as
humidity, moisture and temperature were attached to the device to store the physical
environment data of the fermentation bed. Colour changes during the fermentation
were monitored using an iPhone 6s camera, which have 12 mega pixels. First set of
tea particles from a batch of fermentation was selected for the research. This device
was allowed to collect data until the factory officer asked to stop the fermentation
according to his own decision. A sample of each monitored batch was collected after
firing to measure percentage of Theaflavins. Tea infusion was monitored using
Ultraviolet spectrophotometer. Finally, data were analyzed statistically. Theaflavins
content decreases with the fermentation time which is the trend expected. The average
temperature, temperature difference and average room temperature are statistically
significant with fermentation time at 0.05 level of significance and percentage of
variance is 96.6. Moisture content is constant because this is expected as we focused
on dry season leaves. Finally, study confirms the importance of measuring physical
parameters when monitoring fermentation stage to obtain quality tea. Some advanced
test has to be done on the fermentation tea colour in future.
Keywords: Black Tea, Optimum fermentation time, Theaflavins, Tea quality, Electronic eye
Description
Keywords
Mechatronics