Improvement in Detection of Foreign Fats in Butter.
Year: 1891

page_text: Date of Application, 1st Dec., 1891
Complete Specification Left, 12th Aug., 1892-Accepted, 8th Oct., 1892
PROVISIONAL SPECIFICATION.
Improvement in Detection of Foreign Fats in Butter.
WILLIAM JOHNSTONE Doctor of Philosophy & Science Analytical & Consulting
Chemist & Public Analyst 13 Fish Street Hill Eastcheap London do hereby
declare the nature of this invention to be as follows :-
My improved process for the detection of foreign fats in butter consists in the
identification of the fatty acids which exist in butter & are natural constituents of
it & to the identification of the fatty acids natural to foreign fats & to the estimation
of the quantity of foreign fat added to butter as an adulterant. I proceed as follows.
I saponify with a suitable alkali and estimate the butyric acid.
I then ascertain the amount of iodine absorption possessed by the fatty acids or
glyceride & thereby ascertain the amount of foreign fat added as an adulterant
to butter.
1
1001
WILLIAM JOHNSTONE.
COMPLETE SPECIFICATION.
Improvement in Detection of Foreign Fats in Butter.
I WILLIAM JOHNSTONE Ph. D., D. Sc. Emeritus Fellow of the Institute of
Chemistry, Public Analyst, Analytical & Consulting Chemist 13 Fish Street Hill
Eastcheap London do hereby declare the nature of this invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
My improved process for the detection of foreign fat in butter consists in the
estimation of the liquid glyceride contained in butter. The liquid glyceride I term
oleo-vaccio-butyrate of glycerine. This liquid glyceride is a compound tri-glyceride
containing the three acids, oleic, vaccio butyric in the same molecule, that is to
say that the three radicals of these acids are combined with one molecule of
glycerine to form a molecule of the liquid glyceride & it is to this liquid glyceride
in particular to which butter owes it's particular character & therein differs from
ordinary fats. Seeing therefore that all the oleic acid natural to butter & all the
butyric acid contained in genuine butter are combined in the same molecule it then
becomes an easy matter to detect the addition of a small percentage of foreign fat
as any disturbance of the normal ratio between these two acids will immediately
indicate adulteration.
If there is an excess of oleic acid over the butyric acid it indicates the addition
of animal fat other than butter on the other hand if there is an excess of butyric
acid or volatile soluble fatty acid over the oleic acid the addition of a vegetable
fat may be suspected.
I proceed as follows:-
First. estimate the amount of butyric acid contained in the butter by any
suitable means, and calculate it into the corresponding amount of liquid glyceride,
or oleo-vaccio-butyrate of glycerine, which may be represented by the following
empirical formula:-

page_text: The percentage of butyric acid having been ascertained say 4.68 per cent., the
following calculation is made
CHO, CHO CHÃO, CH„O¸
88
40
6
: . 650 :: 4.68 :
or 34.56 per cent. of oleo-vaccio-butyrate of glycerine.
:-
40
34.56
Second I ascertain the iodine absorption of the butter or of the fatty acids
deriveable from butter by any suitable means.
The percentage of iodine absorbed by the butter, having been found, say
13.455 per cent., it is now calculated into the equivalent of oleic acid thus :-
The percentage of oleic acid thus found is in its turn calculated into its equivalent
of liquid glyceride thus:-
Oleic acid. Liquid glyceride.
282
:
650
::
Oleic acid found.
14.95
: 34.46
or 34-46 per cent. of oleo-vaccio-butyrate of glycerine.
Having obtained these data it now only remains to observe if these two
estimations correspond, namely give the same amount of liquid butter glyceride if
not adulteration is indicated. By operating in the manner above described I can
readily detect, the addition of from three to five per cent. of adulteration, against
the present uncertainty of from 30 to 40 per cent. and in some cases even to
50 per cent., when the Reichert-Wollny figure, or the amount of insoluble fatty
acids, are depended upon as the bases of calculation for estimating the amount of
adulteration.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what 1
claim is :-
The estimation of naccic acid contained in butter and the recognition and
estimation of the impurity of butter by departure from the normal ratio between
the butyric acid and the oleic acid.
2. The estimation of the amount of liquid glyceride contained in butter, as
ascertained in the manner substantially as hereinbefore described.
Dated this Twelfth day of August 1892.
WILLIAM JOHNSTONE.