Method
for the estimation of Bitter content
Solvents
Required:
Methanol, Ethyl Acetate (L.R.Grade)
Glass
wares and Apparatus Required:
R.B. Flask (100mL), Condenser, Beaker (250mL)
Glass rod, Separating funnel, Beaker (150mL).
Procedure:
Weigh accurately about 3.0gm of sample in a
100mL R.B.Flask, add 50mL of methanol and reflux for one hour, cool and filter
through Whatman no.1 filter paper. To the residue in R.B. flask add 50mL of
methanol and reflux for one hour on water bath. Cool and filter through same
filter paper. Again add 50mL of methanol to the residue in R.B flask and reflux
on water bath for one hour. Cool and filter through the same filter paper.
Combine all the three extracts and evaporate methanol completely and dissolve
the residue in distilled water (25mL), warm if necessary to dissolve. Transfer
it in a separating funnel through cotton. Wash the cotton with 10 mL of warm
water. Rinse the beaker with ethyl acetate and transfer to a separating funnel
through cotton. Shake well for 5 minutes. Remove ethyl acetate layer in other
separating funnel. Repeat the extraction of aqueous layer four times more each
of 25mL of ethyl acetate. Combine all the ethyl acetate layer and transfer in a
tare dish. Evaporate on water bath and dried at 105oC in an oven up
to constant weight.
Percentage of bitters (w/w) is calculated as:
(A – B) X 100
------------------------
W
A = Weight of dish + Residue
B = Weight of empty dish
W = Weight of material taken
For Raw
material:
10 gm sample (20#) is to be taken in the case of raw material and the volume of
methanol should be increased accordingly. Proceed the method same as above.
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