182
Components of Fatty Acids of Butter Fats
DISCUSSION
From the analytical data in Table I it will be seen that goat and sheep butterfats have almost
similar characteristics to those of cow and buffalo butterfats. Goat and sheep butterfats have a high
Polenske value and low iodine value. In the case of groundnut vanaspatis with a higher degree of
hydrogenation as indicated by the melting point, there is a gradual decrease in the B. R. index and
iodine value. The mustard oil is characterised from the other fats by a very high iodine value,
and low saponification value, indicating the presence of glycerides of high molecular weight fatty
acids.
The amount of butyric acid in cow butterfat as seen in Tables II and V is higher than in other
butterfats in which the molar percentage of this acid is almost equal. The values for C 6 C 10 acids
in goat and sheep ghee confirm the high Polenske value already described in Table I. The data given
by Dhingra [1937] and Hilditch and Jasperson [1944] are in agreement with present results. The
percentage of lauric acid is also higher in the butterfats of goat and sheep. With regard to percentage
of stearic acid, it is seen that the proportions in buffalo, goat and sheep butterfats are almost similar,
while cow butterfat is richer by about 6.0 per cent in stearic acid content. The sum of myristo-palmi-
to-stearic group acids is, however, constant in all the butterfats. The total of all the acids up to C 14
is higher in case of goat (31.5 per cent, and sheep 32.9 per cent) milkfats as compared to cow (20.3
per cent) and buffalo (21.2 per cent) milkfats. This is mainly caused by the high amount of capric
and lauric acids in goat and sheep butterfats. Arachidic acid is almost similar in all the fats.
The percentage of the lower unsaturated acids C 10 -C 16 in the butterfats is confirmed in the present
study [cf. also Acharya and Banerjee, 1946]. It is found that they are distributed in almost
the same proportion in all the butterfats. The percentage of oleic acid is similar in cow and buffalo
butterfats, while in goat and sheep butterfats, the proportion is found to be much less as will be seen
from Table V. This is in close agreement with the iodine values of the samples. There are marked
variations in linoleic acid content of different butterfats. However, Hilditch has shown that the
amount of this acid in butterfat varies with the diet of the animals as it increases if the animals are
given plenty of green grass. It is found from the data that unsaturated acids higher than C 18 are
also present. No attempt was made to examine this fraction in detail and they have been grouped as
C 20 -C 22 unsaturated acids. The proportions of this fraction in different butterfats were found to
be almost similar.
Our results for palmitic and stearic acids in buffalo ghee agree closely with those of Acharya and
Banerjee [1946]. The amount of oleic acid in the sample analysed here is much higher (26.3 per cent
molar) than the value (17 per cent molar) shown by the above workers. These workers, however,
have not given detailed results and as such no strict comparison can be made.
Our results for the major component acids of goat and sheep butterfats agree with those of Dhingra
[1933]. It is also found (Table V) that the proportions of different acids in sheep butterfats are
almost similar to those of goat butterfat.
The results of the analysis of hydrogenated groundnut oils of m.p. 34.1ºC., 37.0 o C. and 39.0ºC.
are represented in Table III. It is seen from those results that as the melting point increases from
34.1ºC. to 39.0ºC., there is a gradual increase in the content of stearic acid from 6.2 to 12.6 per cent.
Hydrogenation, however, does not seem to affect palmitic acid, arachidic, behenic, and lignoceric
acid contents. Obviously the total amount of saturated acids progressively increases with the rise in
melting point. The percentages of oleic and linoleic acids on the other hand, gradually decrease.
The net result of hydrogenation is the conversion of C 18 unsaturated acids to C 18 saturated acids.
The results of the composition of Indian mustard oil are presented in Table IV. The results
closely agree with those reported by Sudborough et al [1926]. Mustard oil differs from common edible
oils in that it contains a very high proportion of eureic acid (51.0 per cent). The oleic and linoleic
acids are present to the extent of 29.8 per cent and 18.2 per cent respectively. Thus the total un-
saturated acids in the mustard oil are 96.4 per cent, the remaining being made up of small quantities
of myristic, behenic and lignoceric acids.