K. S. RANGAPPA AND B. N. BANNERJEE 69
OBSERVATIONS
(a) Acidity. Acidity increases on storage, but in well-made ghee from healthy animals
the rise is too small to impair its quality. Except in the one-year old sample from Kirkee,
(and this may be due to some lapse in the process of manufacture), the acidity rise is kept down
to well below 1.5 per cent oleic acid. Porbunder samples represent ghee poor in carotene and
vitamin A content with its corresponding property. If these results are compared with those
of Sen Gupta * the importance of the quality of milk in the manufacture of ghee and its
acidity is brought out, He has stored for six months two samples of cow ghee of acid value
1. 0 to 1.5, buffalo ghee of acid value 2.8 and mixed ghee of acid value 0.9 (all bazaar samples,
no source is mentioned) and found the rise to be 1.5, 2.0, 4.6 and 2.1 acid value respectively,
which rendered them useless for analytical purpose or .for consumption. (The acid value is
about twice the corresponding number, expressed as percentage of oleic acid).
(b) H-ion concentration. The H-ion of ghee is not usually determined. But ghee made
by the boiling process—the universal practice in India—retains all the water-soluble con-
stituents of butter. After a number of trials it was found that H-ion concentration of ghee
could be measured in the following way. Ghee 1 c.c. in quantity was shaken with 19 c.c. of
carefully neutralized alcohol of 90 to 95 per cent. strength. The extract was divided into two
parts and tested with methyl red or bromo thymol blue indicator in the usual way. There is
a slight tendency for the H-ion concentration to fall on storage, but the fall is not marked or
regular as is the case with acidity; the pH never falls below 5.2.
(c) Colour. The yellow colour of ghee is mostly due to carotene. It decreases with age
and disappears in 12 months. If ghee is overheated in the clarification process then the colour
disappears much faster. Cow ghee is deeper yellow in colour than buffalo ghee.
(d) Flavour. All the samples of ghee, except those of Porbundar, were good in flavour
for three months. There was degradation in six months; and definite rancid odour developed
in 12 months. Cow ghee is richer in flavour than buffalo ghee.
(e) Texture. On storage, the texture of ghee changes from a firm, granular mass to a
pasty and, finally, greasy consistency. The free fatty acids in ghee are responsible for this
change in a remarkable way. In a stored container the top layer of ghee exposed to air may
be rancid and viscous, while the lower layer might be quite good, firm and granular in
texture.
(f) Vitamin A. The vitamin A content goes down on storage and is reduced to half its
original value in six months, and disappears altogether in a year.
(g) Saponification value. Saponification value of ghee increases on storage, but may
decrease in some cases. It has no correlation with acidity, nor is there proportionality with
storage.
Colour, flavour and texture. These properties of ghee show in a remarkable way the
quality and freshness of a sample. They deteriorate on storage and are fairly proportional
to the development of acidity, and other changes that may be determined by analysis. Flavour
is the most delicate property and is the first to disappear on degradation and storage. Carotene
and vitamin A are the next to go down. Texture and acidity, as mentioned before, are cor-
related with each other. In well-made ghee free fatty acid can be kept very low and the
grain structure and storage property high. With cotton seed feeding, better granular struc-
ture of ghee may be obtained; but unless this is accompanied by carotenoid feeding, the quality
of ghee in flavour, storage property and nutritive elements remains poor.
Composition of the free fatty acids of ghee. In laboratory-made ghee, the acidity is not
high, and the quantity handled never large. Therefore, market samples of ghee were obtained
that had high acidity. Two such samples whose acidity were 4.9 and 14.2 per cent oleic acid
were bought from the market. They were neutralized with alcoholic potash and the resultant
soap was washed out and collected. It was evaporated to dryness, freed from the adhering
ghee by extraction with ether, and then its volatile water soluble fatty acids (R. M.) and its
volatile water-insoluble fatty acids (P. V.) were determined. Its iodine value, lactic acid
content [Friedman et al., 1929], Kirschner value were also determined. The results are given
for comparison with the original ghee in Table III. The percentage composition of the free
fatty acids is also given.
*Sen Gupta (1943). J. Indian Chem. Soc. 6, 158.