FORM 2
THE PATENT ACT, 1970
(39 OF 1970) Complete Specification
(SECTION 2)
1. AN IMPROVED PROCESS OF PREPARING PURIFIED WAXY STARCH
2. CLARIS LIFESCIENCES LIMITED, a Company incorporated In India under the Companies; Act, 1956 having Its registered office at 'Corporate towers" Nr.Parimal Crossing,; Ellisbridge, Abmedabad-380 006 Gujarat State, India
An India Company
The Following specification particularly describes and ascertains the nature of the invention and the nature of the Invention and the manner in which it to be performed.

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3. AN IMPROVED PROCESS OF PREPARING PURIFIED WAXY STARCH.
Field of Invention
This invention relates to an improved process of preparing purified waxy starch.
This invention makes it possible to obtain purified waxy starch wherein proteins is substantially reduced arid purified starch obtained is colourless making suitable as starting material for the preparation of low cost and high quality Hydroxy Ethyl Starch for pharmaceutical applications.
Background of the invention
Purified Waxy starch Is used in the preparation of hydroxy ethyl starch (HES) for
Life saying, pharmaceutical applications.
Normal starches from maize potato, wheat, and rice contain both linear and branched polymer of glucose; Amylose (ref I); is a linear fraction and its presence is hot desirable especially in Hydroxy Ethyl Starch When used for pharmaceutical applications such as plasma volume expander, due to its physical instability. This is because linear molecule tend to undergo a side by side association resulting into; insoluble particles. Waxy starches contain only branched polysaccharide, and! therefore exhibit better physical stability as compared with ordinary starch ; when in the solution. Moreover a branched molecule is supposed to entrap more of the solvent medium with in its branches as compared with linear molecules.
There is a presence of high protein and natural pigments in waxy starch. In alkaline conditions, such as during hydroxyethylation stage in the production of pharmaceutical grade HES, yellow color develops due to the presence of high protein by the way of maillard reaction, This hampers production of colorless HES with protein content of Iess than 0.1%,

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the method described by T J. Schoch (ref-2) for purification of starch containing
high protein to a level of protein content below 0.1% is difficult in practical
execution In as much as the method prescribed requires special equipment such
as continuous flow centrifuge; the process also tends to become expensive.
Further the: temperature prescribed for extraction-is likely to cause gelatinization
of certain grade of waxy starch, making the process less reliable over and above
being cumbersome and expensive.
US Patent no. 4477480 describes the processing of (is starch materials to remove undesirable characteristic thereof. More particularly, a process for reducing the cost and increasing the quality of pregelatinized starches, especially those; pregelatinized starches used in desserts, is disclosed. The said process comprising the steps of:
(a) dispersing and agitating a sufficient quantity of a cereal starch in water So as to form a homogenous starch slurry that is between about 18 and 45%, by weight; starch;
(b) adding an alkali the slurry so that pH is no more than about 2 pH units from the starch's pasting pH;
(c) within about 5 hours of the alkali addition, removing the alkali liquid
from: the slurry;
(d) repeatedly washing the starch solids with an aqueous media, wherein the aqueous media; does not substantially lower the starch pH below a pH Of about 10; and
(e) drying the slurry.
The starch obtained; Is Having high percentage of proteins and also is not colourless. As such it may be suitable for use in food items but it may not suitable for preparing hydroxy ethyl starch for pharmaceutical applications.
The improved: process of: preparing purified waxy starch described herein is simple in; as much as it does not require expensive! equipment or such

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cornpllcated technique; The process ensures reduction of the protein content to less than 0,1% from the initial levels of say more than 0.5% and as well as purified starch obtained is colourless. .
The purified waxy starch so obtained by the process of this invention is the apt starting material for the preparation of low cost and high quality HES for pharmaceutical applications.
Detailed description of the invention
Waxy starch obtained from maize, potato, rice, wheat or any other appropriate source is suspended in purified /deionised water and stirred for about 10minutes, so as to get final solid concentration in the slurry/suspension form in the range of about 16%: by weight. The temperature of the; water taken is kept between 35°C to 37°C by heating if required. :
The suspension is made in a vessel, preferably made from inert plastic or any other vessel, with a surface area, such that about 1cm2 area is available for each 2g to 4g of waxy starch (on dry basis).
The starch slurry/suspension is then made alkaline using 12% to 18% by weight
Volume (equivalent to about 3M to 4.5M) quantity of Sodium hydroxide or Potassium Hydroxide solution, preferably Sodium Hydroxide (cheaper than Potassium hydroxide) to obtain the final pH of between 11.0 to 12.0 preferably
11.5 to 11.8.
The alkali as mentioned above is added slowly and with continuous stirring to
prevent gelation of Waxy starch.
Once the desired pH is achieved, stirring is Stopped and the slurry is allowed to stand for about 6 to 8 hours;, % reaction of protein with alkali.

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At the end of standing period, the supernatant liquid which is yellow to dark yellow in; color due to protein extraction, is removed by decantation.
The residual solid remaining in the vessel is again suspended (second extraction) in purified/deionised water as mentioned above, with; stirring, to get a solid concentration of about 16% and the pH is adjusted between 11.0 to 12.0 preferably 11.5 to 11.8, if required using an alkali as mentioned above, the slurry Is allowed to stand for about 3 to 5 hours, for reaction of remaining protein with alkali.
The process of alkali extraction is repeated third time in the same manner as of second extraction.
The residual solids, of starch, is suspended in purified water to get final solid concentration of about! 16%. The slurry is then neutralized using 4% 4M Hydrochloric acid so that the final pH is between 5.0 to 7.0, preferably 6.0. Slurry is stirred for about 10minutes.
The slurry Is then centrifuged and washed with water such that the final chloride content of the resultant water from washing is not more than 50ppm.
the washed starch with low chloride content is then removed from the centrifuge and dried, using suitable method such as tray drying or spray drying at 70°C to . 80°C preferably 75°C until the moisture content is reduced to 12%.
Example - 1
250 ml of purified/deionised water, heated to about 37°C, is filled into a 500ml
capacity plastic beaker with a surface area of about 48cm2 (diameter about 7:8cm). 100g waxy maize; starch is then slowly added into the water with

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continuous stirring using magnetic stirrer, Once all; the starch is added and dispersed fully, further purified water is added into beaker to make volume to about 400ml. 3.0ml of 4M sodium: Hydroxide Is .then added to slurry prepared above with stirring to get pH; of 11.7. Finally the volume was made with purified water to 500ml Slurry was then stirred for about 10min and allowed to settle. Firsti dedantation wais carried out after 6 hrs when yellow supernatant liquid was removed. Again the volume was made with purified water (temp.30°C) to 500ml and sfurfy stirred. pH was found ;to be 11.6. No alkali was therefore added. Second deqantation was carried otit after 3.5hours and the process repeated as mentioned for second decahtation, 2.0ml of 4M Hydrochloric acid was added to the slurry made after third decantatiori and pH was found to be 6.1.
The slurry was then centrifuged at about 1500rpm and washed twice with purified /deionised water to achieve chloride content-of less than 50ppm in the supematant liquid.
Solids were in the tray and dried in hot air oven at 73°C to 75°C for about 4 hours.
Example-2
250 Lit of purified water, heated to about 36oC, is filled into a 450Lit capacity plastic trough with a surface area of about 15000cm2 (I=w=125cm). 70 kg waxy maize starch having proteins about 0.5% is then slowly added to into the water with continuous stirring using mechanical stirrer; Once all the starch is added and dispersed fully, further purified water was added into trough to make volume to about 400Lit. About 1.5Lit of 4M sodium Hydroxide is then added to slurry prepared above with stirring to get pH of 11:7. Finally the volume was made with purified water to 450Lit. Slurry was then stirred for about 10min and allowed to settle.

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First decantation was carried out after 6 his; when yellow supernatant liquid was removed; Again the volume! was made with purified water (temp.30oC) to 450Lit arid slurry stirred. pH was found to be 11.63. NO alkali was therefore added.
Second decantation was carried out after 3.5hours and the process repeated for third decantation. 500ml of 4M Hydrochloric acid was added to the slurry made after third decantation and pH found to be 6:1.
The slurry was then centrifuged: at about 1200rpm and washed with purified to achieve chloride content of less than 50ppm in the supernatant liquid.
Solids were put in the tray and dried in hot the air oven at 73oC to 75oC for about 5 hours.
The product so obtained was analyzed for protein content by classical Kjeldahl
Method.
Result of analysis

Sr. Characteristics Before purification After purification

01 Description Off white to cream White
02 Protein 0,532% 0.063%
References:

1
2

Studies on starch of high amylose content by w.Banks, C.T.Greenwood and: D.D;Muir.
Preparation and characterization of Hydroxyethyl starch, by T.J.Schoch.

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We claim,

1. An improved process of preparing purified waxy starch comprising of the following
Steps:

a. heating the purified/deionised water kept in inert plastic vessel upto a
ternprature 35oC to 37oC,

b. adding slowly waxy starch in the said water under continuous stirring to obtain solid concentration in the slurry form of about 15% by weight,

c. adding 12% to 18% (equivalent to about 3M to 4.5M) of Sodium hydroxide or Potassium Hydroxide into the slurry formed in a step (b) to obtain pH between 11 to 12.

d. Adding water and stirring the slurry for about 10 minutes and allowing to settle for alkali treatment for about 6 hours and decantation supernatant yellow colour liquid,

e. Adding purified/deionised water to the residual solid waxy starch of step (d) and stirring the slurry and allowing to settle for alkali treatment for about 3.5 hrs and decanting supematant yellow colour liquid, repeating this step one more time to active colourless supernatant liquid,

f. adding 4M Hydrochloride acid to slurry of the step (e) to obtain pH between 5 to 7,

g. centrifuging the slurry of step (f) at about 1200 to 1500 rpm and washing the slutty with purified/deionised water to obtain chloride content less than 50ppm,

h. drying the residual starch of step (g) in hot air at temerature about 70oC to 80oC for about 4 hours to reduce the moisture content up to 12% and abtaining purified colourless waxy starch containg protesins less than 01.%,

2. An improved process of preparing purified waxy starch substantiales as herein described an illustrated in the examples 1 & 2.

Dated 19th September, 2000

ABSTRACT
An improved process of preparing purified waxy starch from such sources as maize, rice, potato and wheat is described so as to reduce the protein content. Waxy starch treated with alkali such as Sodium Hydroxide or Potassium Hydroxide at a specified pH range for a definite period of time. At the end of such period the protein alkali complex is removed and waxy starch is washed and dried. This invention makes if possible to obtain purified waxy starch, which is apt starting material for the preparation of low cost and high quality Hydroxy Ethyl Starch for pharmaceutical and other application.