N. S. DOCTOR, B. N. BANERJEE AND Z. R. KOTHAVALLA 67
was determined by the method recommended by Mohr [1925] and adopted
by Lyons [1936]. Refractive index measurements were taken on an Abbé
refractometer at 40°C. and converted to butyro-refractometer readings at
40°C. The carotene content was determined by the method of Ferguson
and Bishop [1936]. Vitamin A determinations were made colorimetrically
using the B. D. H. Lovibond tintometer with Carr and Price reagent (SbCl 3 ,
saturated solution in CHC1 3 ) on the unsaponifiable matter. The other
physical and chemical constants were determined by standard methods.
The averages of the results of the various determinations for each sample
of butterfat were calculated and are given in Table III.
The results obtained also represent the individual variation. While
the individuals of different breeds do not show any appreciable change in the
various constants of their butterfat, the variation due to different breeds of
animals is remarkable. The foreign breeds of cows show the remarkable
property of transferring more carotene from the food to the fat than Indian
breeds of cows. Buffalo ghee is always characterized by its higher content
of butyric acid and very low content of carotene. In all these cases a close
correlation has been observed between the refractive index and iodine value.
A high refractive index corresponds to a high iodine value. The refractive
index, however, does not vary between such wide limits as the iodine value.
EFFECT OF FEEDING OIL CAKES ON CHEMICAL AND PHYSICAL CONSTANTS OF GHEE
The concentrates available for feeding the dairy cattle in this country
depend on the oil seed or grain grown in different areas. Thus, in Gujarat,
Kathiawar and other areas where cotton is extensively grown, only cotton seed
is fed ; in certain areas in the South, only coconut cake is fed. In other parts
gingili, linseed, or groundnut cake is fed. The effect of feeding such rations
high in vegetable fat on the composition of butterfat has been much studied and
it is now well known that feeding different oils and fats does to some extent
change the chemical composition of the butterfat, the modification depending
on the composition of the oils and fats fed [Holland et al., 1918, 1923 ; Cranfield,
1911, 1916; Channon et al., 1924; Hilditch, et al., 1930, 1931; Eckles and
Palmer, 1917 and others].
This has caused difficulties in fixing an all-India standard for grading
and marketing of ghee (Rept. Ghee Conference II, Agriculture Marketing, Jan.
1938). Therefore, an experiment was conducted under conditions similar
to those practised in the villages, where free use of oil cake is made, with
the view to studying the effect of oil cakes on the analytical constants of
ghee.
A number of Sindhi cows were selected from the Imperial Dairy Institute
herd and were kept on a general ration for periods sufficiently long (four
weeks) to cause the butterfat to approach constant composition before col-
lecting the experimental samples.
Particulars of the cows used.—Ten Red Sindhi cows were selected. They
were all in early lactation. The cows were divided into five groups of two
each (Table IV). The members of each group were more or less similar in
live weight and milk yield and were receiving the following ration of concen-
trates :—