An Improved Method of Preventing the Curdling of Albuminous Solutions.
Year: 1891

page_text: Date of Application, 24th Nov., 1891-Accepted, 23rd Jan., 1892
COMPLETE SPECIFICATION.
An Improved Method of Preventing the Curdling of Albuminous
Solutions.
1, JOHAN EDVARD ALEN, of Gothenburg in the County of Bohustán, Kingdom
of Sweden, Town-chemist, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:—
My invention relates to a method of preventing albuminous solutions from
curdling which quality among others forms a very essential obstacle to the proper
testing and controlling of milk, because the latter often cannot be conveyed to the
milk testing station, without curdling on the way (in consequence of the coagulation
of the albumen) which renders the testing impossible or difficult.
This method consists in adding to the fresh milk a small quantity of a soluble
chromate which mixture is then stirred up. The quantity of the mixture depends
on the quantity of the albuminous solution, as also on the temperature, to which the
solution is exposed, and on the time, for which the curdling is to be prevented.
If the curdling is only to be prevented for a short time for instance for 24 hours
only an inconsiderable quantity of the chromate is required, but if the curdling is
to be prevented for a longer time, the quantity of the mixture must be increased.
If the albuminous material, as milk, is to be preserved in a higher temperature,
somewhat more of the said mixture than usual must be added. For the preservation
for a longer time of albuminous solutions it is preferable to use a little quantity
of the chromate and a low temperature instead of a greater quantity and a
higher temperature. As an example it may be stated here, that a quantity of
only 0.05 grammes of bichromate of potassium prevents the curdling of 200 cubic
centimetres of milk at the usual temperature for 12 days; in the same way a
mixture of 2 grammes of the same salt has prevented the curdling of 500 cubic
centimetres of milk during 4 months. A quantity of 0.01 grammes of a chromate
could therefore probably be sufficient, to prevent the curdling of 100 cubic
centimetres of milk at a usual temperature for a time of 24 hours, although the
said quantity may without injury be increased a thousand fold. If the curdling of
the same quantity of milk is to be prevented for one or two months, an addition
of 0.1 to 2 grammes or more of the same salt will probably be suitable.
Although all soluble chromates would probably be applicable for the purpose
in question, the bichromate of potassium will probably be the most suitable ou
account of its cheapness and of its being easily procured. In conclusion it will be
well to add, that a part of the albumen in milk coagulates immediately, if to a
relatively small quantity of milk, a relatively large quantity of chromic acid is
added.
I have also found, that the addition of some soluble chemical combination of
mercury to milk has the same effect as the addition of some chromate, on which
account the effect of the latter can be still more increased by a further addition of
any soluble chemical combination of mercury in a proportion of 0.005 to 0.5 grammes
to 100 cubic centimetres of milk.
The milk treated in the manner above mentioned by way of example for the
testing of albuminous solutions, is of course not applicable as food, it being only
intended for the testing of milk, thus permitting a comprehensive and exact testing
of milk, by the testing of a sample collected during several successive days, that
is to say a sample of the milk can be taken every day and mixed with the chromate
(and eventually also with the soluble combination of mercury) to prevent the
curdling. The samples thus prepared can then be mixed together to form a
general sample which can be sent to the chemist if for example the chemical station

page_text: is situated some distance from the place of production. The milk therefore does
not need to be sent to the chemical station for testing every day, but can be stored
up for several days.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what I
claim is
An improved method of preventing the curdling of albuminous solutions by the
addition of a soluble chromate and eventually also of a soluble chemical combination
of mercury.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.