Improvements in the Preparation of Rennet Powder for use in Cheese-making.
Year: 1889

page_text: Date of Application, 2nd Nov., 1839-Accepted, 7th Dec., 1889
COMPLETE SPECIFICATION.
Improvements in the Preparation of Rennet Powder for use in
Cheese-making.
I, RICHARD DENDY, of the West of England Annatto and Rennet Works, Bishop's
Sutton, near Bristol, Somersetshire Manufacturer 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:―
This invention relates to the preparation of a Rennet-powder for use in cheese-
making, and consists in a process combining simplicity and economy in the means
employed, without any perceptible loss of the active principle of the rennet. By all
known methods hitherto described, the processes of extracting a pure ferment in such
a form as to satisfy the requirements of cheese-makers have been very complicated,
involving several distinct operations, during which the extract assimilates certain
surrounding impurities, besides occupying a considerable time in the process; but
by the method which I have discovered, Lclaim that nearly the whole of the rennet
ferment is utilised, and that the ferment is prepared in such a manner as to be
practically free from any impurities.
In the manufacture of rennet powder according to the processes hitherto described,
the powder is produced from a liquid extract, containing either (1) a small quantity
of salt with the addition of some preserving substance or substances, such as mineral
or organic acids, or (2) a larger quantity of salt alone, but in no instance exceeding
10 per cent. From extracts made according to either of these methods, the powder
which is obtained by super-saturating the extract with salt, will not exhaust the
whole of the ferment, and a second process is necessary to cleanse the powder from
impurities acquired during the super-saturating operation, and by this second process
more of the ferment is lost.
After numerous experiments and observations, I have found that raw extracts
containing less than 12 per cent. of salt undergo rapid decomposition unless
mineral or organic acids or other preservatives are added, and that the filtration of
extracts so prepared is a long and tedious operation, owing principally to the
quantity of mucus held in suspension if only the described or any less proportion of
salt has been used in preparing the extract; while the addition of acids also tends to
make filtration more difficult, besides detracting from the value of the product. I
have also found that by using a larger quantity of salt in preparing the extract, it
may be kept fresh and good for a considerable time without the employment of any
acid whatever, and that the more salt is used up to 18 per cent. the smaller will be
the quantity of mucus and other impurities liberated from the vells and mixed
with the extract, consequently the work of filtration is greatly simplified and
shortened.
According to this invention, I prepare my rennet powder in the following
manner the vells are finely divided and macerated in a brine containing from
12 to 18 per cent. of common salt; after remaining in the same for some time, the
ferment will be dissolved, and in consequence of the increased quantity of salt used,
the mucus will be retained with remnants of the vells and other impurities, these
impurities are strained from the liquid, and the liquid is filtered in the ordinary way,
a clear extract being thus obtained; to this extract I add a further small quantity
of salt, not exceeding 5 per cent., which will precipitate the greater part of the
ferment, this precipitate or deposit, being practically pure and free from any
injurious matter, may be at once dried, either in vacuo or under ordinary atmospheric
pressure, at a temperature not exceeding 35° cent., additional salt being added to
the precipitate, either before, during, or after the drying process, according to the
degree of concentration required. The result of the evaporation will be a powder
ready for use in the manufacture of cheese.

page_text: The remaining extract, which will still contain some of the active principle, with
a very small proportion of albumenoids, and a relatively small quantity of salt, being
pure and clear can be at once brought into use, either in the preparation of liquid
extract of rennet, or may be sold and used as a weak rennet solution.
By the means herein described, I produce a rennet powder with the necessary
admixture of preserving salt, without the use of acids or other objectionable matter;
and although by this process I do not obtain the whole of the ferment in the powder,
the remainder is utilised in either of the two ways above mentioned.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is -
1. The process of obtaining rennet extract by steeping the vells in a brine solution
containing from 12 to 18 per cent. of salt, (whereby the mucus and other impurities
are separated from the rennet), and filtering the solution, the result being a strong
rennet extract.
2. The process of obtaining rennet powder from an extract prepared as described,
by the addition thereto of a small quantity of salt, not exceeding 5 per cent., the
deposit thereby produced being dried at a temperature of about 35° cent., whereby a
strong powder is obtained, which is attenuated by the addition of salt according to
the strength required.
3. The process of manufacturing rennet powder as herein before described by the
addition of salt only, thus obviating the use of acids or other chemical substances,
which, while detrimental to the ripening of the cheese, may possibly interfere with
the active principle of the rennet.
Dated 1st Novemba 1000
J. G. WESTLAKE,
Applicant's Agent.