Improved Process for Producing Soluble Starch.
Year: 1898

page_text: Date of Application, 26th May, 1898
Complete Specification Left, 22nd Feb., 1899-Accepted, 20th May, 1899
Improved Process for Producing Soluble Starch.
-
I, Dr. FERDINAND VIRNEISEL, of 223, Friedrichstrasse, Berlin, in the Empire
of Germany, do hereby declare the nature of this invention to be as follows:-
This invention relates to a wet process for converting ordinary starch and sub-
stances containing starch into soluble starch.
As is generally known, the conversion of starch into soluble starch, by wet
process, requires, even at a temperature reaching to 40° Celsius, not less than
per cent. hydrochloric acid or 15 per cent. sulphuric acid, and from 3 to 8 days
digestion. Such a method is not therefore commercially practicable. More-
over, so much dextrine and sugar is formed in the process, that the loss in starch
is very considerable.
The inventor has ascertained that the starch can be made soluble with 1 to
2 per cent. of acid and in from 12 to 24 hours, if the process be carried on at
a temperature of from 50° to 55° Celsius, and that, in such case, the formation
of dextrine and sugar is avoided.
According to this invention if technically pure starch be treated, (potato, maize,
rice, wheat starch, etc.) 1000 parts of dry starch are mixed, with 1000 parts of
water at a temperature of 60° Celsius, and containing 2 per cent. of sulphuric
acid. The mixture is then heated to 55° Celsius, and kept at from 50° to 55°
Celsius until the conversion has been completely effected. The process of conver-
sion takes from 12 to 15 hours. The starch is then washed, subjected to centri-
fugal action and dried..
If wet starch be treated (starch with about 50% water) a smaller quantity of
water is taken. In using maize, rice, wheat, barley and other granular vegetable
substances one and a half times to double the quantity of water is used with 2%
sulphuric acid at a similar temperature of 55° Celsius.
Instead of sulphuric acid other mineral acids or organic acids can be used,
but sulphuric acid is the cheapest material for the conversion.
The pure converted starch is free from dextrine, sugar, acids, alkali, completely
soluble in hot water and likewise in cold weak alkaline solution. As the soluble
starch forms a clear solution with hot water it penetrates fibrous material more
thoroughly than ordinary starch. The converted starch can thus be employed
in many ways in the textile and other industries. The conversion of the starch
also is of great advantage in connection with the production of spirits, beer, sugar
and the like.
Dated this 26th day of May 1898.
I, Dr. FERDINAND VIRNEISEL, of 223, Friedrichstrasse, Berlin, in the Empire
of Germany, do hereby declare the nature of this invention and in what manner
[Price 8d.]

page_text: the same is to be performed to be particularly described and ascertained in and
by the following statement:-
This invention relates to a wet process for converting ordinary starch and sub-
stances containing starch into soluble starch.
As is generally known, the conversion of starch into soluble starch by wet
process, requires, even at a temperature reaching to 40° Celsius, not less than
7 per cent. hydrochloric acid or 75 per cent. sulphuric acid, and 3 days
digestion. Such a method is not therefore commercially practicable. More-
over, so much dextrine and sugar is formed in the process, that the loss in starch
is very considerable.
The inventor has ascertained that the starch can be made soluble with 1 to
2 per cent. of acid and in from 12 to 24 hours,, if the process be carried on at
a temperature of from 50° to 55° Celsius, and that in such case, the formation
of dextrine and sugar is avoided. At this temperature the cellulose of the grains
of starch are most sensitive to the action of the diluted acids, but nevertheless,
sufficiently resistant to preserve the structure of the grains of starch, which con-
sequently, pass into the soluble form in shorter time, the hydrating action thus
extending only to the cellulose of the grains of starch.
According to this invention if technically pure starch be treated, (potato, maize,
rice, wheat, starch, etc.) 1000 parts of dry starch are mixed with 1000 parts of
water at a temperature of 60° Celsius, and containing 2 per cent. of sulphuric
acid. The mixture is then heated to 55° Celsius, and kept at from 50° to 55°
Celsius until the conversion has been completely effected. The process of conver-
sion takes from 12 to 15 hours. The starch is then washed, subjected to centri-
fugal action and dried.
If wet starch be treated (starch with about 50% water) a smaller quantity of
water is taken. In using maize, rice, wheat, barley, and other granular vegetable
substances one and a half times to double the quantity of water is used with 2%
sulphuric acid at a similar temperature of 55° Celsius.
Instead of sulphuric acid other mineral acid or organic acids can be used,
but sulphuric acid is the cheapest material for the conversion.
The pure converted starch is free from dextrine, sugar, acids, alkali, completely
soluble in hot water and likewise in cold weak alkaline solution. As the soluble
starch forms a clear solution with hot water it penetrates fibrous material more
thoroughly than ordinary starch. The converted starch can thus be employed
in many ways in the textile and other industries. The conversion of the starch
also is of great advantage in connection with the production of spirits, beer, sugar
and the like.
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:
The conversion of ordinary starch and substances containing starch into soluble
starch by wet process, the distinguishing feature of which is that the starch or
substances containing starch is digested with water, containing from one to
two per cent. of mineral or organic acid at a temperature of from 50° to 55°
Celsius, the digestion being continued until the starch has been converted into a
soluble form, the starch being then washed with water, the material so obtained
being then fit for use in a wet or dry state.
Dated this 22nd day of February 1899.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.