36
REPORT OF THE KING INSTITUTE, GUINDY
To test what could be done I visited the Agricultural Dairy at . Coimbatore, where
churning experiments were carried out for me under my supervision. Samples of butter were
prepared both with and without the use of ice and I took samples at various stages of the
churning for analysis. Using no ice the finished. butter made from buffalo milk cream
contained. 15.5 per cent of moisture, from cow's milk cream 16.5 per cent. Six samples from
Coimbatore Dairy, at other times, forwarded to me by post have contained. from 14.5 to 17.4
per cent of moisture, the higher percentages being always obtained in cow's butter which
contains a softer fat than buffalo's butter. The samples prepared. for me without the use of
ice were churned in the early morning (about 7 a.m.), the temperature in the churn being
77° F. It would probably be unreasonable to expect every small dairy to use ice, otherwise
the English limit of 16 per cent might be adopted; but the figures that I have obtained
show that working under the best conditions without ice a butter containing very little more
moisture can be prepared. To allow for the fact that the technique of the churning at
Coimbatore was probably a little better than that obtaining in the ordinary small dairy,
I suggest that for the present a limit of 20 per cent be adopted. A proportion of water in.
excess of this will, in my opinion, be due either to deliberate over-churning, working at mid--
day temperatures or insufficient working of the butter, any of which will cause an increased
moisture content and an unduly large yield of butter.
I have examined a number of samples of butter purchased casually in Madras. I have
only found one sample with less than 20 per cent of water, this sample was from a small dairy
and contained 19.8 per cent, other samples have contained. from 20.5 to 27.9 per cent (ten
samples), one sample from a Madras dairy contained 57.5 per cent. Hence the adoption of a
20 per cent limit would involve considerable improvement, but I do not consider that dairies
would find any real difficulty in producing a butter of this quality.
Ghee is prepared by heating butter until all moisture has disappeared, and should contain
no moisture whatever. I suggest that a 1 per cent limit be allowed for adventitious moisture,
any moisture in excess of this amount will have been. fraudulently worked in. In England a
1 per cent limit was prescribed during the war for moisture in lard, which as a normally
anhydrous fat corresponds in some respects to ghee in India.
The natural standard for the fat in butter or ghee is the adoption of the definition. given
in the Act, i.e., it must be exclusively milk fat.
In some countries so-called standards have been prescribed fixing limits to which certain
analytical constants of the fat must subscribe. The authorities in England have always
refused to countenance any such standard, and I most strongly recommend that the same
policy be adopted in Madras.
The figure which has been. mainly used is known to chemists as the Reichert number.
Fats consist of a complex mixture of what are known as "glycerides." These are
compounds of glycerine with certain organic acids known as the "fatty acids." There are a
large number of these glycerides, one of which is the glyceride of butyric acid. It happens
that butter is the only fat which contains this glyceride in any considerable proportion and
the Reichert number is roughly proportional to the butyric acid present. At first sight it
might appear that the fixing of a minimum Reichert number would be of assistance to the
Analyst. The difficulty lies in the fact that although butter-fat is the only fat which gives
a considerable Reichert figure, the value of this figure for genuine butters is very variable,
the maximum figure being about double the minimum.
In Europe most butters have a Reichert value lying between 25 and 33. In Madras I
have obtained Reichert values below 15 (from butter made from the milk of a single cow in
the General Hospital herd), while other butter-fats have given values of more than 30.
Only four figures below 20 were obtained out of 81 determinations so that it might be
suggested that a figure of 20 should be adopted as a minimum limit; this would, in my
opinion., be extremely inadvisable. Should an Analyst obtain a Reichert value of 20, he
would know, after the publication of this report, that the sample under examination might be
genuine. On the other hand it might have been prepared by the adulteration of a sample of
butter of high butyric content, thus it might consist of a mixture of 66 per cent of butter of
a, Reichert value of 30 with 33 per cent of adulterant, such a mixture would yield a Reichert
value of about 20. He would next proceed to apply tests for certain specific adulterants
which are commonly used for adulteration and the presence of which is readily detected. He
would further determine a number of other constants than the Reichert value and in spite of
the sample having given a Reichert value consistent with the sample being genuine he
might obtain figures which could not be given by genuine butter-fat. There are certain
adulterants which could be added to a butter of high Reichert value and which could not
at the present moment be detected, in such a case an Analyst must give the vendor the
benefit of the doubt and pass the sample as genuine, but in the other cases mentioned the
onus of proof should a standard Reichert value be adopted, would lie with the prosecution,