Joint International Conference on Long-term Experiments ...

Column extraction (Beck, H. and Mathar W. 1985)
Mix 10 ml of liquid milk sample in a mortar with see sand and sodium sulphate (1 + 1
mix) to obtain a dry friable product. Transfer the mix in the extraction glass-tube
(interior diameter 12 mm and 300 mm length). Before this, introduce in the tube a tap of
“glass cotton” and a layer of 2 cm of sodium sulphate, for dehydration. Eluate the
column with a mix 2:1 (v/v) n-hexane and acetone. Collect the eluate and evaporate it in
a spinning evaporator at approximately 50 ºC under reduced pressure, using balloons of
constant weight to determine fat.
Partition extraction (SR EN 1528-2, 2004)
In a 1000 ml glass, add 100 g milk, 500 ml 2:1 (V/V) n-hexane and acetone mix and
homogenize for 4 minutes. Allow phases to separate. Decant the superior organic layer
in a separation funnel which contains 500 ml sodium sulphate solution. Add in the glass
50 ml 2:1 n-hexane-acetone mix and decant in the separation funnel to ensure the
qualitative transfer of the organic phase. Agitate the separation funnel for 30 seconds.
Allow phases to separate and remove inferior, watery phase.
Agitate the organic layer with another 500 ml sodium sulphate solution. Remove
inferior layer as before but keep about 2 ml in the funnel. Spin the separation funnel
around its axis to remove all the water from the vase’s walls. When all water settled,
drain the remaining watery phase and remove it. Put approximately 20 g sodium
sulphate with frit glass and pass the organic phase through the sodium sulphate in a
round bottom balloon which has been weighted first. Evaporate the solution in a
spinning rotator at approximately 50 ºC under reduced pressure.
RESULTS AND DISCUSSIONS
For each separation method, the final phase is the one when the solvent is removed
through evaporation and the fat is determined gravimetrically.
MG = (M2 –M1) / M1
% GR = MG /M X 100
MG - FAT MASS
% GR – FAT PERCENTAGE
M – MASS OF THE WORKING TEST
M1 – mass of the recipient where extracts are collected, empty
M2 – mass of the recipient where the extracts are collected, after removing the solvent
Note : for the column extraction method we determined the density of the test because
the methods implies the introduction of a certain volume, while the calculus refer to the
masses.
The results obtained are presented in the tables 2 and 3 for the two types of test in work.
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