BIVOLTINE RACE AND

8.0. COCOON DRYING : ': :
The primary objectives of drying cocoons are to kill pupae before they emerge and to kill
maggots of parasitic moths and flies if any, before they emerge from the pupae.Secondary
objectives are to reduce the water content of fresh cocoons to minimise the chances of fungal
infection during the period of storage so that the quality of cocoons becomes suitable for
subsequent processing.
8.I. Hot air drAing
The best method of cocoon drying is done at different temperatures for 6 hours. The weight
of green cocoons is recorded before drying.
Drying of cocoons is generally done by setting the initiai tenrperature with the range of
95-60'C and then Lry lowering the temperature gradually as drying progresses. Finally, drying
is completed at the temperature of around 60"C.
The procedure adopted for green cocoon drying is detailed below.
1) At the first one hour
2) At the second hour
3) At the third hour
4) At the fourth hour
5) At the fifth hour
6) At the sixth hour
In step wise drying, one should check the temperature every one hour following the above
mentioned standard method. At the beginning the moistuie in the cocoon is very high, so that
high ternperature is.preferred. After one hour of drying at 95'C, moisture in the cocoon is
decreased, then iow temperature is suitable for cocoon drying.
After five hours of drying, the first coeoon weight should be recorded. The second cocoon
weight should Lre recorded after drying again at 60'C for 30 rninutes. If the first and second
cocoon weight found same, one can assurne that drying is completed. Then the percentage of
the driage rnay be calculated. However, the standard drying percentage is calcuiated from
cocoon shell ratio.
9.0. R-EELXNG TEST
The test reeling centres have to process the eocoons as mentioned below.
Out of 1000 reeling cocoons, first 600 coeoons to be reeled are taken at random and
divided into two tlatches of 300 cocoons each. All the reeling parameters are to be sturiied. In
case, for any character, if the deviation of the results in the two tratches is significant, then the
ttrird batch of 300 cocoons are to be reeled again and the results are obtained. Then average
is calculated. The remaining 100 eocoons are tcl be used only for cooking test.
Note :
95"C (drying temperature)
93"C
90"c
85'C
75"C
60"c
300 : 300 : 300 : the cocaon weigttt shoutd be taken und the weiglrt b be nmde equal by interchanging
the cocoons among them.
Ihe results obtuined out of three batches, the batches which are shawing chqrscters nearer only to be
taken for calculqtion of average datn.
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