POSSIBILITIES OF ADDING SESAME OIL TO HYDROGENATED FAT
OR VANASPATI, TO DISTINGUISH IT FROM GHEE
By ZAL R. KOTHAVALLA, NOSHIR N. DASTUR and K. G. BHIDE,
Imperial Dairy Research Institute, Bangalore
(Received for publication on 14 August, 1943)
SEVERAL varieties of hydrogenated vegetable
fats have been put on the market at present, which
closely resemble ghee in almost all their physical
characteristics. To distinguish ghee from such
hydrogenated fats has therefore become a matter of
great concern with the consumer. The problem is
analogous to the problem of butter vs. margarine
in Western countries. To facilitate the detection
of adulteration of butter with margarine, it has
been made compulsory in Austria, Belgium, Den-
mark, Finland, Germany, Portugal, Sweden and
Switzerland to a
5 to 10 per cent of sesame oil to
the latter. By this means margarine is easily dis-
tinguished from butter by the well-known Bouda-
nin or Villavecchia test. This investigation was
therefore undertaken to explore the possibilities of
adding sesame oil to hydrogenated fats to facilitate
their detection when mixed with ghee.
In the past whenever this subject received atten-
tion from the authorities concerned, objections
were raised to the adoption of such a precau-
tionery measure by the manufacturers of
hydrogenated fats on the ground that, as sesame
oil had a relatively high iodine value, it was likely
to lower their keeping quality. No data had,
however, been obtained so far to prove if this was
really so and to what extent the quality of hydro-
genated fats was actually likely to be affected by
the addition of sesame oil in different proportions.
This and related aspects of the problem have there-
fore been carefully determined by this investigation.
EXPERIMENTAL
(1) Effect of adding sesame oil on the keeping
quality of hydrogenated fats. Two different com-
mercial brands of hydrogenated fats, one made
from groundnut oil (Brand A) and the other from
cottonseed oil (Brand B) were used for these
studies. Sesame oil, after being freed from any free
acids and suspended matter, was mixed with these
samples in the proportions of 5, 10, 15 and 20 per
cent. The samples were kept in glass bottles and
exposed to diffused light. A sample of each of the
two original brands was also kept under identical
conditions as control. The keeping quality was
measured in terms of peroxide value at intervals by
the method described by Dastur and Lea [1940].
The results obtained are given in Tabes I and II.
The peroxide values are expressed in terms of
N/500 sodium thiosulphate.
TABLE I
Peroxide values of hydrogenated fat Brand A (ml. of N/500 thiosulphate)
Weeks
Hydrogenated fat .
5 per cent S. oil .
10 „ „ „ .
15 „ „ „ .
20 „
„
„ .
Original
1.33
1.69
2.72
2.86
2.94
IV
3.80
4.86
5.14
5.86
6.44
VIII
9.93
11.87
13.04
14.80
16.60
XII
14.33
16.38
18.04
19.77
22.82
XVII
14.92
17.71
19.98
22.33
25.64
XX
19.95
22.92
24.83
28.36
31.53
XXIV
25.39
28.34
30.80
35.27
39.76
XXVIII
31.37
35.08
37.69
41.87
47.82
TABLE II
Peroxide values of hydrogenated fat Brand B (ml. of N/500 thiosulphate)
Weeks
Hydrogenated fat .
5 per cent S. oil .
10 „
„ „ .
15 „ „ „ .
20 „
„ „ .
Original
1.66
2.30
3.25
3.33
3.65
TV
2.75
3.77
4.93
5.63
6.13
VIII
5.89
9.12
11.46
13.09
16.49
XII
8.14
12.25
16.32
18.63
21.29
XVII
8.94
13.98
15.00
22.09
25.17
XX
13.07
18.26
21.18
27.13
32.28
XXIV
17.87
22.39
26.34
32.09
37.94
XXVIII
22.22
26.90
31.50
37.83
44.81
163