Improvements relating to the Manufacture of Soluble Starch.
Year: 1893

page_text: Date of Application, 15th Mar., 1893
Complete Specification Left, 10th Nov., 1893-Accepted, 23rd Dec.. 1893
PROVISIONAL SPECIFICATION.
[Communicated from abroad by WILHELM ANGELE, of Bülowstrasse No. 41,
Berlin, in the Empire of Germany, Civil Engineer.]
Improvements relating to the Manufacture of Soluble Starch.
1, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent Agents,
45 Southampton Buildings in the County of Middlesex, do hereby declare the
nature of this invention to be as follows:-
:―
This invention relates to the production of so-called "soluble starch," a product
well adapted for use as a thickening agent in many technical processes such as
dyeing cloth-printing dressing, glazing of paper and the like.
As is well known soluble starch is a derivative of amylum having the appearance,
structure and other properties of common starch but differing therefrom by perfect
dissolubility in hot or boiling water without being gelatinized. From the so-called
"white dextrine," which is another derivative of amylum, the soluble starch or
amyloide" as it is called by the inventor, is easily to be distinguished by perfect
indissolubility in cold water, insipidity, inodourousness, and absence of sugar.
66
Hitherto soluble starch has been prepared for scientific purposes exclusively by
subjecting starch (amylum, fecula) to the action of a considerable quantity of
hydrochloric acid of 7-5% at ordinary temperature, or of sulphuric acid of 15%
at a moderate temperature, washing the product of the conversion with water in
order to remove the acid, and drying.
It will be readily understood that this method is not adapted for manufacture on
a large scale for the reason of too great quantities of acid and water being
required.
Now the inventor has found that it is possible to bring about the conversion of
starch, (amylum, fecula) into "amyloide in a very perfect manner by means of a
quantity of acid which is only one tenth of that deemed necessary in the above
mentioned laboratory process.
Based on this fact the present invention consists in operating in the following
manner.
Dry starch (amylum, fecula) is intimately impregnated with so much of diluted
hydro-chloric (hydrofluoric, nitric, sulphuric, phosphoric, oxalic, lactic, acetic, or
other) acid that the mixture obtained contains about 0-5-1 part of acid free from
water for every 100 parts of perfectly dry starch. The mixture of starch and acid
is very advantageously produced by means of an agitating device or of an atomizer.
This mixture is allowed to stand and dry at a temperature not exceeding
40° centigrade, until a sample taken therefrom dissolves in hot or boiling water
without being gelatinised, when the conversion is complete. The lapse of time
necessary for this will in general be 48 hours or about, but it may be considerably
reduced by first extracting from the mixture a part of the water by centrifugal
action. In this case, however, a correspondingly greater quantity of acid has to
be employed. The product of the conversion is stirred with water and then freed
from the acid by repeated lixiviation with water, to which may be added
neutralizing agents. After lixiviation the remaining water is separated from the
product by first submitting it to centrifugal action, and then drying it in the same
manner as starch is treated in the manufactories.
The above described process may also be employed to produce amyloidle from
wet or green starch, i.e., freshly prepared starch which is not yet deprived of water.
In this case the impregnation with the acid may be carried out in the washing vat,

page_text: before or during the extraction of the water, or within the dryer during the drying
process.
Dated this 15th day of March 1893.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements relating to the Manufacture of Soluble Starch.
I, HENRY HARRIS LAKE, of the Firm of Haseltine Lake & Co., Patent Agents,
45 Southampton Buildings in the County of Middlesex 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 production of the so called "soluble starch" by
means of acids, and its object is to so improve this acid process that it will permit the
product to be manufactured on a large scale, soluble starch being well adapted for
use as a thickening agent in many technical processes such as dying, cloth printing,
dressing, glacing paper, &c.
The product called "soluble starch" is known as being a derivative of amylum
having the appearance and structure as also other essential properties of ordinary
starch but differing therefrom by the caracteristic property that, in lieu of being
gelatinized when treated with hot or boiling water, it forms a clear limpid solution.
From the so called "soluble dextrine," which is another derivative of amylum, the
soluble starch or "amyloide," as I call it, is caracteristically distinguished by
perfect indissolubility in cold water, insipidity and inodourousness, absence of sugar
and an absolute neutral reaction.
Soluble starch although its aforesaid properties make it a very advantageous
thickening agent, has hitherto been prepared in very small quantities only and for
analytic purposes exclusively, for determining for inst. the diastatic power of
malt. The reason for this limited use will be readily understood from the nature
of the method employed which, up to the present invention, was the only one
known for producing soluble starch by the aid of acids. This method is as
follows: Starch (amylum, fecula) is subjected to the action of a considerable
quantity of hydro-chloric acid of 7.5 per cent. at ordinary temperature or of
sulphuric acid of 15 per cent. at a moderate temperature, so much of the acid being
added that it stands over the surface of the starch. When the conversion is
complete, the product is freed from the acid by washing with water and finally
dried. It is evident that a method based on the employment of so large a quantity
of a comparatively strong acid and requiring so large quantities of water for
extracting this acid, is not adapted for production on a large scale.
Now I have found that the conversion into amyloide of any kind of starch
or amylum or fecula can be effected in a very perfect manner by the aid of a
quantity of acid that is but one tenth of the quantity that was required by the old
method, in proceeding so as to intimately impregnate the starch with this acid and
allow the mixture to dry slowly at a temperature from about 26 to 40° centigr.
At a temperature exceeding 40° conversion into dextrine will take place, whilst at
a temperature below 26° centigr., the conversion into amyloïde is incomplete.
During exposure to the said temperature the acid, having penetrated into the inner-
most part of the grains of starch, is concentrated gradually by the evaporation of its
water and when sufficiently concentrated effects the conversion. As the final
product contains but little acid, it is evident that but a correspondingly small
quantity of water is required for extracting the same by lixiviation.
The process may be carried out with hydrochloric, hydrofluoric, nitric,
sulphuric, phosphoric, oxalic, lactic, acetic and other liquid or volatile acids.
And in order to enable my invention to be carried out to best advantage.
I proceed to describe one way which I have found to give very good results.

page_text: Dry starch, or amylum, or fecula, is intimately mixed by means of an agitating
device with so much of diluted hydrochloric acid that the mixture contains
about 0.5-1 part of acid free from water for every 100 parts of perfectly dry
starch. This quantity of acid is diluted with as much water as is required for
obtaining a stiff paste of such consistency as just to permit its being stirred. For
instance 1000 kilogrammes of dry starch are mixed with 1000 litres of water to
which are added 20-40 kilogrammes of an hydrochloric acid containing
25 per cent. HCl. The impregnation of the starch with the acid can also be
effected by the aid of an atomizer by which the acid is sprinkled in finely divided
state over the starch, the latter being simultaneously subjected to a repeated
turning over. The mixture is placed in a drying room on hurdles as in ordinary
starch drying and allowed to dry at a temperature of about 21 to 40° centigr.
The drying is continued until a sample taken from the mass dissolves in hot
or boiling water without being gelatinized; when this is arrived at the conversion
is complete, and the mass is taken from the dryer for further treatment as
hereinafter described. The lapse of time necessary for complete conversion will in
general be 48 hours or about and it depends in a certain degree of the more or less
perfection of the drying plant. It may considerably be reduced by first extracting
from the mixture a part of the water by the aid of a centifrugal. In this case,
however, the mixture must be prepared with so much acid that it originally
contains 5-10 kilogrammes of the latter for every 100 kilogrammes of starch, in
order that the mixture contains the required quantity of acid after centrifuging.
The excess of acid expressed together with the water from the mixture by the
action of the centrifugal may then be made use of for preparing fresh mixtures.
At the same time the action of the centrifugal causes a very intimate penetration
of the acid into the starch.
The mass taken from the dryer, which constitutes a mixture of soluble starch and
acid, has now to be freed from the latter. For this purpose it is first stirred with
cold water in order to extract the greater quantity of the acid, and the remainder
of the same is taken away by repeated lixiviation with cold water to which
neutralizing agents may be added such as alkaline carbonates. After disacidi-
fication the water remaining behind in the amyloïde is separated therefrom by
first centrifuging and then drying in the same manner as starch generally
is dried.
The described process can also be employed to produce amyloide from wet or
green starch, i.e. freshly prepared starch being not yet deprived of water. In this
case the impregnation of the starch with the acid may be effected in the washing
vat before or during the extraction of the water in employing such excess of acid
as is required for leaving a proportion of acid as stated in the deshydrated
starch, or the acid may be added to the starch in the dryer by means of an
automizer during the drying process.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, as communicated to me by my
foreign correspondent, I declare that what I claim is :
The improved process of producing amyloïde or soluble starch having the
appearance and structure of ordinary starch and dissolving in hot water without
gelatinizing consisting in mixing starch (amylum, fecula) with diluted acid in such
proportion that the mixture contains 0-5-1 part about of the same for every
100 parts of perfectly dry starch, allowing the mixture to dry at a temperature of
from 26 to 40° centigr. until it dissolves in hot water without gelatinizing, freeing
the product from the acid by washing with cold water, and drying it, substantially
as set forth.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.