Year: 1886

page_text: I, HERBERT JOHN HADDAN, of 67, Strand, in the County of Middlesex, Civil
Engineer, do hereby declare the nature of this invention, a communication to me
from abroad by Moritz Blumenthal, Doctor of Philosophy, of Grünau near Berlin,
Germany, and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
This invention relates to the manufacture of rennet and consists in a process for
obtaining the rennet free from mucous substances.
The dried rennet, extracts or powder employed heretofore by the process in
which they are made contain besides the efficient principle of the rennet, various
other constituents of the calves stomach which contain mucus and albumine, and
also large quantities of the salt used for preserving, these admixtures being .
detrimental to the ripening process in the manufacture of cheese.
The object of the present invention is to manufacture the pure principle of
rennet "chymosin" which shall be free from these admixtures.
In the improved process the vets are cut into small pieces and the rennet is
extracted by means of a solution containing about 5 per cent. of salt, to which is
added a small quantity of a mineral acid, (muriatic sulphuric, phosphoric or boracic
acid) which separates the mucous substances. The extract will contain the whole
of the principle of the rennet but with little of the mucous substances.
It is now filtered and subsequently, while continuously agitating is mixed with
powdered salt of an alkali or alkaline earth soluble in water until it is perfectly
saturated, Ordinary salt is preferably used. After the mixture has been standing
for a certain time, the principle of the rennet "Chymosin," is almost completely
precipitated.
The precipitate may subsequently be purified by again dissolving it in water
and precipitating by means of salt, or by washing with concentrated solution of a
Boluble salt of an alkali or alkaline earth such as ordinary salt, whereby it is freed
from acids and other impurities present in small quantities.
The precipitate of rennet is then dried and powered. The pure rennet may now
be mixed with sugar, mineral or organic acid, or a salt of the alkalies or alkaline
earths for allowing it to be conveniently measured for use.

page_text: Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is:
1. The pure pulverised principle rennet (" Chymosin ") manufactured as described
and combined with a soluble salt of the alkalis or alkaline earths, especially
cooking salt, or with sugar or a solid mineral or organic acid soluble in water.
2. The process of separating the pure principle of rennet (* Chymosin") free of
mucus by mixing the extract of the rennet with an excess of a soluble salt of the
alkalis or alkaline earths in pulverised state, preferably cooking salt, strongly
agitating the mixture and subsequently allowing it to stand until the precipitate
is obtained.
3. The process of purifying rennet containing or free from mucus and obtained
from an acid solution consisting in washing with a concentrated solution of a
soluble salt of the alkalis or alkaline earths, especially cooking salt, for the purpose
of removing acids and other impurities.