Abstract:
Theanine is a non
-protein amino acid representing as much as 50% of the total amino acids in
black tea and 1
%
- 2%
of dry weight in green tea. It has been shown to be able to reduce high
blood pressure, promote relaxation, and inhibit caffeine’s side effects among others. This current
study explored the effects of sunlight and withering durations on theanine levels in
tea shoots.
Theanine content from three leaves and a bud, two leaves and a bud and internodes were detected
and quantified
by
using High Performance Liquid chromatography (HPLC). Sunlight exposure ex-
periment was started at dawn (0600
HRS
, GMT + 3.0
0) when
the light intensity was low and tea
was collected at three
-hour interval throughout the day to (1800
Hrs, GMT + 3.0
0) when the light
intensity ha
d dropped. At the start of the experiment, the theanine levels were significantly high
but as the intensity of
sunlight increased during the day there was a significant drop in theanine
levels, and as the sun set the theanine levels increased significantly again in all samples. The r
e-
sults also showed that theanine levels were significantly increased after 15 hour
s of withering.
Three leaves and a bud withered for 3 hours had mean theanine levels of 1.41% and those withered
for 15 hours had mean theanine levels of 3.11%. Internodes exhibited higher mean theanine levels
than those of leaves. In the light of these results
, it’s evident that withering for a longer period of
time and harvesting of tea when th
e light intensity is low ensure
high amount of theanine in tea.
