144
KEEPING QUALITY OF GHEE
[VOL. XX, PART II,
Ghee samples collected from different centres in India
Samples were obtained from ten centres. Special instructions were issued to
parties concerned to purchase milk and prepare ghee as per instruction. Butter
was not to be melted at a temperature exceeding 120°C. The ghee soon after pre-
paration was to be packed in clean tins and despatched to Bangalore. Inspite of
these instructions, it was found that ghee was sometimes over-heated and some of
the tins were heavily rusted with the result that samples were already rancid when
received at Bangalore. The results of such samples are not given here. The samples
on arrival at Bangalore were heated at 60°C., filtered, transferred to glass bottles
and stored at 37°C. The results of this study are given in Tables IV and V. For
obvious reasons the names of parties who supplied the samples are not given but
only the place of the origin of the sample is indicated.
DISCUSSION
(i) Farm produced ghee samples. The results of keeping quality of farm samples
are given in Table I. These samples were prepared by the ordinary method taking
no special precautions. Over a period of nearly seven months only ten samples out
of 17 showed peroxide values exceeding 5.0, but in a majority of cases it was well
below 2.0. These low peroxide values were recorded inspite of the fact that the
samples were stored in clear glass bottles and they were therefore occassionally
exposed to light during the course of analysis. That light is a very powerful catalyst
for oxidation is now well established [Dastur and Banerjee, 1936 ; Lea, 1931]. The
results also show that for preparing ghee of good quality high temperature is not
necessary. Ghee prepared carefully either at 60°C. or 120°C. had equally good
keeping quality. The data show that cow and buffalo ghee samples when properly
made and stored with reasonable care keep good for a fairly long period.
The figures for acidity reveal that all the samples had very low acid value. Similar
results were obtained for both the first and second batch of ghee and to avoid repeti-
tion, results for only the second batch are given, as in this series ghee was prepared
from the same samples of butter at two temperatures. In no case was the acid value
over 0.50 per cent oleic, a figure which is well below the stand for ' special quality '
Agmark ghee (1.5 per cent oleic). Method of preparation, or the breed of the animals
had little effect on the development of acidity.
Banerjee and co-workers (loc. cit.) have shown that the main causes of develop-
ment of high acidity in ghee are the use of raw milk for preparing curds, long storage
of curds and unwashed butter, and incomplete removal of moisture and associated
impurities during the preparation of ghee. The data given confirm this conclusion.
(ii) Effect of feeds on the keeping quality. That different types of feed effect the
chemical composition of ghee has now been well established [Doctor et al., 1940 ;
Anantakrishan et al., 1947]. As the object of the present study was to find out if
different feeds affect the keeping quality of ghee, the data for composition are not
given here. The keeping quality of butter as well as of the butter fat was studied.
In appearance butter fat obtained from animals receiving cakes was much whiter
in colour compared to samples from other animals. All the butter samples as soon
as prepared were judged for texture and aroma by a panel of judges. They were
then stored at room temperature for seven days and again judged. On storing for