NOSHIR N. DASTUR, D. R. KASHYAP AND ZAL R. KOTHAVALLA 59
The results obtained with the Tile test using
different types of fats are briefly summarized as
follows:
(a) Vegetable oils. All the edible oils tested gave
negative results, i.e. left no chalky mark on the
surfaces tried.
(b) Vanaspati samples. In all 25 different
brands of vanaspati were examined. It was found
that, with a single exception, all the samples left
a chalky mark on the tile. It was also noticed
that this particular sample which gave the negative
result was quite hard compared with the other
samples of vanaspati, which were in a semisolid
condition at room temperature.
(c) Animal depot fats. These fats were extrac-
ted from the connecting tissues by the application
of heat. Cow's and goat's depot fats gave a chalky
deposit, while buffalo's and pig's fats showed
negative results. It may be added that at room
temperature, the buffalo fat was found to be as
hard as either cow or goat fat.
(d) Ghee samples. In all about hundred samples
of ghee were examined by the ' Tile ' test. Sam-
ples were collected from almost all parts of the
country with great care to ensure their genuineness.
For this test, the direct use of butter instead of
ghee made no difference as to its sensitivity. It
was found that approximately 45 per cent of these
ghee samples gave a positive result. The rest
were negative. This serious defect indicates the
unreliability of the test under everyday conditions.
(e) Effect of heating the fats on the tile test. It was
found that when vanaspati samples which gave a
positive ' Tile ' test were heated to 60° C. and
higher, they lost the property of throwing the
chalky deposit on the tiles. Melted samples were
always allowed to cool to room temperature by
leaving them overnight, and in some cases were
even solidified by keeping them in a refrigerator
before testing. This behaviour of vanaspati is a
great handicap in the application of the Tile test.
(f) Detection of adulteration using tile test. In
view of the fact that quite a large number of gen-
uine ghee samples gave a positive result, the utility
of this method for the detection of adulteration of
ghee, therefore, becomes very doubtful.
These results suggest that the positive results
given by most of the vanaspati samples and other
fats is due to the peculiar physical condition at the
time of their examination rather than to any in-
herent characteristic.
PRESENCE OF NICKEL IN VANASPATI
A study to estimate the nickel content of
vanaspati was undertaken. Any results of a simi-
lar study, if carried out in India, have not been
published. If nickel is found to be present in
vanaspati in considerable proportions due to faulty]
methods employed in its manufacture, the test could
then be utilized for the detection of such vanaspati
if added to ghee.
For detecting the presence of nickel, an acid
extract of the fats under test was prepared
by the method recommended by Atack [1913]
using Fortini's reagent as follows : 50 gm. of fat
were weighed in a flask and 20 ml. of concentrated
HCl added to it. The mixture was heated with
frequent shaking and then allowed to stand. The
TABLE I
Samples.
Vanaspati No.1
„ 2
„ 3
„
4
„ „
5
„ 6
„
7
„
8
„ 9
„
10
„ 11
„
12
„
13
„
14
Vanaspati No.15
„ 16
„ 17
„
18
„
19
„
20
„
21
„
22
„
23
„
24
Ghee
Bombay
Bombay
Jubbulpore
Jodhpur
Jodhpur
Jodhpur
Ajmer
Bangar
Darbhanga
Darbhanga
Calcutta
Calcutta
Calcutta
Calcutta
Narnaul
Bangalore
(buffalo)
Bangalore (cow)
Mandya
Bellier-Kries reaction
Upper layer
(other)
Brown
„ „
„
„ „
„ Pink
Brown
„ „
„
Turbid
Brown
Colourless
Colourless
„ Pink
„
Brown
„
„ „
Brown
Yellow
Pink
Faint pink
Pink
Colourless
Pink
„
Faint pink
„ Brown
„ „
Faint pink
„ Colourless
Faint pink
Faint brown
Colourless
Faint brown
Lower layer
(acid)
Colourless
„ „
„ „
„
„ Pink
Colourless
„ „
„
„
„ Faint pink
Colourless
„ Pink
„ Colourless
„
„
„ Colourless
Yellow
Brown
Yellow
Brown
Colourless
Faint pink
„ „
Yellow
„ Brown
„ Yellow
Colourless
„ Yellow
„
Colourless
Yellow
Remarks.
The
lower
layer
changed to deep red
after some time.
The
lower
layer
changed to reddish
brown.
The
upper
layer
changed to faint
pink and the ower
to yellow.