K. T. ACHAYA AND B. N.
BANERJEE
149
The Kirschner value. This has recently been strongly advocated by Sen Gupta [1943]; since
it varies largely with the R.M. value, little is to be gained by encumbering the R.M. process with a
further K.V. determination.
The neutralization value of Hawley [1940] whose merit is that it measures the water-insoluble
acids, as it were, by omitting butyric acid, is not likely on theoretical grounds to have wide appli-
cation, since it is not merely the variations in content of butyric acid alone that affect the simple
S.V., but changes in the other acids as well. An extended trial, especially of ghees from cottonseed-
feeding areas which contain very little butyric acid but large proportions of stearic acid, should prove
the point.
The Ave-Lallement value has been shown long ago by Plymen and Aiyer [1921] and later by
Parthasarathi and Banerjee (unpublished work) to have very little value since positive values were
often obta . To quote a few of the figures of the latter workers, cows fed on the cakes mentioned
low gave baryta values as shown :
Groundnut +10.3
Gingilli
+8.0
Linseed
+0.1
........
Cottonseed + 4.7
Coconut
+16.4
Moreover, a genuine sample of buffalo ghee from the Kathiawar district gave a figure of+23, while
another sample gave a value as low as —15.5.
The colour-firnges of Godbole and Sadgopal [1939] obtained on an uncompensated butyro-
refractometer have been shown by Dastur, Kashyap and Kothavalla [1944] to be of no help in the
detection of adulteration, colours from violet to red being obtained as against the colourless or light
violet claimed by the originators. Besides, the colours closely followed the refractive index as might
be expected.
The ' A' and ' B ' values, also strongly recommended by Godbole and Sadgopal [1939] have
still to be tried on the different types of ghee available in India. though we anticipate that these cum-
bersome determinations would have little advantage over the simpler R.M. P.V. procedure.
The enzymic hydrolysis method of Giri and Bhargava [1937], while obviously of little quantitative
or qualitative use in the detection of adulteration, indicates a field for future work. If an enzyme
capable of selectively splitting butyric acid from a glyceride could be found, it would enable a perhaps
rapid and certainly easy method of estimation of butyric acid, results which would be useful in the
detection of fraudulence.
The thiocyanogen value has recently been suggested as a weapon against adulteration, since in.
combination with the iodine value, an estimation of the linoleic acid is possible in milk fat. Achaya
and Banerjee [1945, 1] have shown that the content of this acid in buffalo ghee is only about 1 per-
cent and that most oils and hydrogenated oils have very high contents, so that even slight adultera-
tion would greatly raise the normal percentage of the acid in ghee. It is hoped that extensive work
on these lines will be undertaken, since fixing the limits for the variation occurring in genuine samples
is a half-way house to the detection of sophistication. Correlation with the other analytical cons-
tants might also be looked for. The only two drawbacks are the low contents of linoleic acid in coco-
nut oil (which however could be detected by the R.M. -P.V. relationship) and in animal fats.
The fluorescence of ghee in ultra-violet light has recently been studied by Achaya and Banerjee
[1945, 2] who state that yellow pigments and/or vitamins mask the true fluorescence colour of. ghee.
On thorough bleaching with animal charcoal of fresh samples, a characteristic light green colour was
obtained, which turned progressively blue as rancidification proceeded. Since most adulterants of
ghee fluoresced blue, any sign of blue in a bleached ghee would indicate either bad quality or adul-
teration. The apparatus required is simple : a source of ultra-violet light, from perhaps a mercury
are, and a light filter to cut off visible light; the time required for the test is very short—the samples
after bleaching are merely viewed in ultra-violet light. The method is strongly recommended as a
routine sorting test in an analyst's laboratory.
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