Fbb i, 1902.] THE TEOPICAL AGRICULTURIST. 
the latter, '■ total enzyme," though probably ft part 
of this does not exist ready formed in the leaf, 
and may hence be known as " zymogen " or " pro- 
enzyme." 
OXIDISING ACTION OP THE FEBMENT. 
After isolating these substances the first question 
would naturally be as to what effect they have 
when added to fermenting tea leaf. The experiment 
was therefore made, and it was found that the leaf 
coloured more quickly in their presence and at the 
same time the colouring proceeded normally. The 
same happened if tea juice instead of tea leaf was 
taken. It may therefore be taken that the ferment 
which I have isolated does play a part in the fer- 
mentation of the tea. This was confirmed by its 
action on several other easily oxidiaable substances. 
Pyrogallic Acid, for instance, coloured (i. «., oxidised) 
with great rapidity in its presence. Hydroquinone 
did the same. So that we have here an oxidising 
enzyme or oxidase, present in the tea leaf, capable 
of causing increased rapidity of fermentation in the 
tea, and capable of oxidising various easily oxidi- 
sable substances like Pyrogallic Acid and Hydro- 
quinone. 
EFFECT OF HEAT, &C,, ON THE FEKM«ST. 
The next point appeared to be to ascertain the 
effect of heat upon this oxidase, especialiy as this 
has an important bearing on the temperature ne- 
cessary to stop the fermentation at the commence- 
ment of firing. It was found that a temperature of 
160-165°F. had no appreciable effect in three minutes, 
that at 176*F. the oxidase was partly destroyed on 
the same time, but it was not till over 180°F. 
was reached that the ferment was completely de- 
stroyed in this period. On the other band its acti- 
vity is considerably modified at a much lower tem- 
perature. I could not ascertain the precise point at 
which it ceased to be effective, but while very active 
at iac»F., it was much more feeble at US^F., and 
doubtless at a very short distance above this it 
ceased altogether to exercise its functions. It ia 
therefore absolutely necessary that the whole of the 
tea in the drying machine fand not merely the 
machine, thermometer, which is a very different thing 
be raised considerably above 150'F. immediately on 
putting in the firing machine, and to ensure the 
destruction of the ferment at least 180°F. should 
be reached. This is of course what is attained in 
the best practice, but the reason and necessary for 
it become obvious when considered in the light of 
the above observations. 
The effect of various chemicals on the oxidase was 
next considered. It acts best in slightly acid solu- 
tion, bat if this acidity be increased especially with 
mineral acids, beyond a small amount, all action 
ceases and the enzyme may be destroyed. '4 pet 
cent, of Sulphuric Acid in a liquid was sufficient to 
absolutely destroy the ferment at once. -04 per cent 
apparently hindred all oxidising action. To organic 
acids such as those which occur in tea juice it was 
much less sensitive, and 3 per cent, of Acetic Acid 
were required to destroy it in 2 hours. Alkalies 
were less effective, but here 3 per cent, of Ammo- 
nia or Caustic Potash were sufficient to practically 
destroy the active part of the enzyme after four 
and a half hours. The result in manufacture of 
these observations I have not as yet been able to 
ascertain. Whether it may be wise or practicable 
to make up the leaf to a certain definite acidity, 
being the point at which the ferment was most 
active, before fermentation, one cannot at present 
say. It is well known that Hydrochloric Acid added 
to the roll softens and weakens the liquor,* but in 
this case the acid itself is objectionable, and we 
have no record of the amount added. This is a 
matter for experiment. 
! Sea Tea Notes. A. F. Dowling. 1885. 
DISTRIBUTION OF FEHMENT IN THE FLtTSHINO SHOOT. 
If the various leaves on a flushing shoot be taken, 
the amount of enzyme is by no means the same in 
every part. The fresh leaf, for instance, contains 
about an equal amount in the unopened tip leaf 
and in the stalk, but below the tip the percentage 
decreases in every leaf. Taking the leaf as plucked, 
for instance, on a China-hybrid bush in September, 
the following table gives the relative amount present 
in each leaf separately, calculated both on the fresh 
leaf and on the dry matter in the leaves (taking 
that in the tip leaf as unity) : — 
Active Enzyme. Total Enzyme. 
a 
O 
1-00 
•64 
•48 
1^13 
a 
o 
1-00 
•65 
•48 
1-64 
leaf. 
(S 
<B 
m 
<o 
£• 
u 
m 
a 
o 
a 
O 
100 
•64 
•61 
(•80 ?) 
(•80 ?) 
•95 
139 
Unopened tip leaf . . 
First open leaf . . 
Second open leaf ... 
S3talk 
These figures apparently seem to indicate that 
where the largest quantity of enzyme ia present; the 
best tea is made, and yet not wholly so, because 
the stalk, which is objectionable in the tea, contains 
as much as any part. The reason of this is seen 
however if the relative amount of acidity, of tannin, 
and of phosphoric acids in the same samples of these 
leavee are taken. These give the following figures : — 
Acidity. Tannin, Fhosphoi; 
Acid, 
u 
13 
a 
Tip nnopened ., I'OO l^OO 100 1-00 1 00 1*00 
leaf 
First open leaf ... ^94 ^94 103 1.03 '88 '88 
Second open leaf.. ^94 ^94 ^91 ^91 -75 '75 
Stalk ... '47 -70 -59 ^86 '55 -79 
It therefore appears that, where a large amonnt 
of enzyme is combined with tho greatest acidity, 
and with the greatest amonnt of tannin, there the 
tea produced ia the best. Snch ia only a prelimi- 
nary conolnsioD, and it must strictly be considered 
applicable to similar conditions. It is, however, one 
to which the next set of experiments gives support. 
RELATION or FERMENT TO QUALITT. 
Several gardens were taken in the Darjeeling 
District. A produces average or rather better 
than average Darjeeling tea ; B has for many 
years produced absolutely the beat tea in India ; 
C ia during the present season giving the 
highest priced product in the district. Condi- 
tions being therefore aa near as possible equal, the 
quality, if the above condition be true, should 
vary according to the amonnt of enzyme present, 
provided the same amount of stalk, or approxi- 
mately so, be present in the samples. Comparing, 
first, garden B with garden A. B No. 3 ia from a 
young Assam or high hybrid extension giving very 
fine tea ; B No. 2 ia from a low level Assam ex< 
tension giving the worst tea on the garden, but yet 
an above-average quality ; B No. 3 is from China 
tea giving an exoellently flavoured product. Deter- 
mining the enzyme present in each of these samples 
in September 1900, and comparing the amount with 
that in A (Chiutk hybrid plant), have, takicK 
A as unity. 
