U.S. patent application number 09/758555 was filed with the patent office on 2001-08-23 for method and apparatus for producing a pre-gelled starch product and normally sticky extrudates with minimal or no surfactant.
Invention is credited to Huber, Gordon R., Plattner, Brian S., Renyer, Douglas D., Strahm, Bradley S., Sunderland, Robert D..
Application Number | 20010015138 09/758555 |
Document ID | / |
Family ID | 27384679 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010015138 |
Kind Code |
A1 |
Huber, Gordon R. ; et
al. |
August 23, 2001 |
Method and apparatus for producing a pre-gelled starch product and
normally sticky extrudates with minimal or no surfactant
Abstract
An improved low shear extrusion and dehydrating apparatus (10)
and method is provided for the continuous extrusion of various
starting materials (e.g., starch-bearing grains or starch fractions
thereof, proteinaceous materials and/or nutraceuticals) to yield
improved products, especially cold water swelling or soluble starch
products. The invention is also useful for forming pre-gelled
starch products and for processing starch-bearing materials using
little or no surfactant. The apparatus (10) preferably includes an
elongated extruder (18) together with a tubular die assembly (20)
coupled to the outlet of the extruder barrel (32), wherein the
volumetric ratio of the die assembly (20) to the free volume of the
extruder (18) is at least about 2, and the ratio of die assembly
retention time to the extruder retention time is at least about 5.
In another embodiment, the apparatus (10) further includes a
dehydration assembly (14) having an agitator (56) operatively
coupled to a drying or dehydrating tower (66) for drying and
comminuting the extrudate after it emerges from die assembly
(20).
Inventors: |
Huber, Gordon R.; (Sabetha,
KS) ; Strahm, Bradley S.; (Sabetha, KS) ;
Plattner, Brian S.; (Sabetha, KS) ; Renyer, Douglas
D.; (Wetmore, KS) ; Sunderland, Robert D.;
(Sabetha, KS) |
Correspondence
Address: |
HOVEY WILLIAMS TIMMONS & COLLINS
2405 GRAND BLVD., SUITE 400
KANSAS CITY
MO
64108
|
Family ID: |
27384679 |
Appl. No.: |
09/758555 |
Filed: |
January 11, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09758555 |
Jan 11, 2001 |
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09344468 |
Jun 25, 1999 |
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6247394 |
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09344468 |
Jun 25, 1999 |
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09135203 |
Aug 17, 1998 |
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09344468 |
Jun 25, 1999 |
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09249648 |
Feb 12, 1999 |
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Current U.S.
Class: |
99/353 ; 99/355;
99/483 |
Current CPC
Class: |
B29C 48/535 20190201;
B29C 48/42 20190201; A23P 10/40 20160801; B29C 48/761 20190201;
A23P 30/20 20160801; A23L 29/212 20160801; A23L 7/117 20160801;
A23L 7/143 20160801 |
Class at
Publication: |
99/353 ; 99/483;
99/355 |
International
Class: |
A23L 001/00; A47J
009/00; A23C 003/02 |
Claims
We claim:
1. Extrusion cooking apparatus comprising: an elongated extruder
including a tubular barrel having an outlet end and at least one
elongated, axially rotatable helically flighted screw within the
barrel for moving material through the barrel, said extruder having
a free volume within said barrel; a drive for axially rotating said
screw; and a tubular die assembly operatively coupled to said
barrel adjacent said outlet end thereof and including an elongated,
tubular body with an apertured die secured to the end of the
tubular body remote from said extruder barrel, the volumetric ratio
of said die assembly to said extruder free volume being at least
about 2.
2. The apparatus of claim 1, said volumetric ratio being from about
3-20.
3. The apparatus of claim 1, said drive being operable for axially
rotating said screw at a rate of at Least about 300 rpm.
4. The apparatus of claim 1, including a pair of axially rotatable
screws within said barrel.
5. The apparatus of claim 1, said extruder having an L/D ratio of
from about 5-14.
6. The apparatus of claim 1, said die including a substantially
centrally located, inwardly extending, flow-directing member.
7. The apparatus of claim 1, further including a dehydrating
assembly for receiving an extrudate from said die assembly and
partially dehydrating said extrudate.
8. The apparatus of claim 7, wherein said dehydrating assembly
comprises: a receiver presenting a chamber positioned to receive an
extrudate from said die assembly and an agitator within said
chamber; apparatus operable to deliver a heated air stream to the
chamber of said device in order to partially dehydrate the agitated
extrudate therein; and an upright dehydrating tower having a
material inlet operatively coupled to said receiver for receiving
said partially dehydrated extrudate from said receiver.
9. The assembly of claim 8, said dehydrating assembly further
including a separator operably coupled to said tower for separating
dehydrated extrudate from said air stream as the extrudate rises in
said tower.
10. The assembly of claim 9, wherein said separator is a cyclone
separator.
11. The assembly of claim 8, said agitator comprising a plurality
of arms mounted radially on a rotating shaft, each of said arms
including a pair of blades disposed so that the free edges of said
blades form cutting edges directed in the direction of rotation of
said shaft.
12. The assembly of claim 8, said tower further including a
material outlet, the distance between said inlet and outlet being
from about 8-25 feet.
13. Extrusion cooking apparatus comprising: an elongated extruder
including a tubular barrel having an outlet end and at least one
elongated, axially rotatable helically flighted screw within the
barrel for moving material through the barrel, said extruder having
a free volume within said barrel; a drive for axially rotating said
screw; and a tubular die assembly operatively coupled to said
barrel adjacent said outlet end thereof and including an elongated,
tubular body with an apertured die secured to the end of the
tubular body remote from said extruder barrel, said extruder and
die assembly cooperatively configured for establishing a retention
time ratio of die assembly retention time to extruder retention
time of at least about 5.
14. The apparatus of claim 13 said retention time ratio being from
about 7-15.
15. The apparatus of claim 13, said drive operable for rotating
said screw at a rate of at least about 300 rpm.
16. The apparatus of claim 13, including a pair of axially
rotatable screws within said barrel.
17. The apparatus of claim 13, said extruder having an L/D ratio of
from about 5-14.
18. The apparatus of claim 13, said die barrel including a
substantially centrally located, inwardly extending, flow-directing
member.
19. The apparatus of claim 13, said extruder retention time being
from about 3-20 seconds.
20. The apparatus of claim 13, said die assembly retention time
being at least about 15 seconds.
21. The apparatus of claim 20, said die assembly retention time
being from about 50-600 seconds.
22. The apparatus of claim 13, further including a dehydrating
assembly for receiving an extrudate from said die assembly and
partially dehydrating said extrudate.
23. The apparatus of claim 22 wherein said dehydrating assembly
comprises: a receiver presenting a chamber positioned to receive an
extrudate from said die assembly and an agitator within said
chamber; apparatus operable to deliver a heated air stream to the
chamber of said device in order to partially dehydrate the agitated
extrudate therein; and an upright dehydrating tower having a
material inlet operatively coupled to said receiver for receiving
said partially dehydrated extrudate from said receiver.
24. The assembly of claim 23, said dehydrating assembly further
including a separator operably coupled to said tower for separating
dehydrated extrudate from said air stream as the extrudate rises in
said tower.
25. The assembly of claim 24, wherein said separator is a cyclone
separator.
26. The assembly of claim 23, said agitator comprising a plurality
of arms mounted radially on a rotating shaft, each of said arms
including a pair of blades disposed so that the free edges of said
blades form cutting edges directed in the direction of rotation of
said shaft.
27. The assembly of claim 23, said tower further including a
material outlet, the distance between said inlet and outlet being
from about 8-25 feet.
28. A method of processing a product comprising the steps of:
passing said product in serial order through an extruder and a die
assembly to yield an extruded product, said extruder comprising an
elongated, tubular barrel having an outlet end with at least one
elongated, axially rotatable, helically flighted screw within the
barrel, said die assembly including an elongated, tubular body
operatively coupled to said barrel adjacent the outlet end thereof,
and an apertured die coupled to said body adjacent the end thereof
remote from said extruder; and during said passing step, rotating
said screw at a rate of at least about 300 rpm, and causing said
product to experience a retention time ratio of die assembly
retention time to extruder retention time of at least about 5.
29. The method of claim 28, said retention time ratio being from
about 7-15.
30. The method of claim 28, the retention time of said product in
said extruder being from about 3-20 seconds.
31. The method of claim 28, the retention time of said product in
said die assembly being at least about 15 seconds.
32. The method of claim 31, the retention time of said product in
said die assembly being from about 50-600 seconds.
33. The method of claim 28, including the step of controlling the
temperature of said product within said extruder to a maximum of up
to about 150.degree. C.
34. The method of claim 28, including the step of controlling the
pressure within said extruder to a maximum of from about 50-2000
psi.
35. The method of claim 28, said product being a starch-bearing
product selected from the group consisting of potato, tapioca,
grain, root and tuber starches, rice, wheat, oats, barley, corn
rye, and mixtures thereof.
36. The method of claim 28, including the step of subjecting said
product to a preconditioning step prior to passage thereof through
said extruder, said preconditioning step including the steps of
adding moisture to the product and heating the product.
37. The method of claim 28, including the step of drying said
product after passage thereof through said extruder and die
assembly.
38. The method of claim 28, said product being essentially free of
added surfactant.
39. The method of claim 36, the retention time of said product in
said preconditioner being at least about 15 seconds.
40. The method of claim 28, further including the steps of:
agitating said extruded product; and pneumatically passing said
agitated product through a dehydrating tower.
41. The method of claim 40, wherein said agitating step comprises
placing said extruded product into the chamber of a receiver having
an agitator within the chamber, said agitator comprising a
plurality of arms mounted radially on a rotating shaft, each of
said arms including a pair of blades disposed so that the free
edges of said blades form cutting edges directed in the direction
of rotation of said shaft, said shaft being rotated during said
agitating step so that said blades contact said extruded
product.
42. The method of claim 40, wherein said agitating step comprises
contacting air having an impact temperature of from about
300-550.degree. C. with said extruded product.
43. The method of claim 40, wherein said dehydrating tower has a
material outlet and said passing step comprises applying negative
air pressure to said outlet.
44. The method of claim 43, wherein said negative air pressure is
applied by a cyclone separator having a material outlet to create
an air flow through said separator for further drying the product
and for separating said product from said air flow.
45. The method of claim 44, further including the step of passing
said separated product through said cyclone material outlet, and
wherein the amount of time that passes from the beginning of said
agitating step to the time when the product passes through said
cyclone material outlet is less than about 15 seconds.
46. The method of claim 40, wherein the residence time of said
agitated product in the tower is from about 1-2 seconds.
47. The method of claim 40, wherein the product resulting from said
pneumatic passing step has a moisture content of from about 0.5-18%
by weight, based upon the total weight of the product taken as 100%
by weight.
48. The method of claim 40, the retention time of said product in
said extruder being from about 3-20 seconds.
49. The method of claim 40, the retention time of said product in
said die assembly being at least about 15 seconds.
50. The method of claim 40, wherein the maximum temperature of the
product within said extruder is up to about 150.degree. C.
51. The method of claim 40, wherein said starch is selected from
the group consisting of grain, root and tuber starches and mixtures
thereof, and starch-bearing grain products selected from the group
consisting of rice, wheat, oats, barley, corn, rye, and mixtures
thereof.
52. The method of claim 40, further including the step of
subjecting said product to a preconditioning step prior to passage
thereof through said extruder, said preconditioning step including
the steps of adding moisture to the product and heating the
product.
53. The method of claim 40, further including the step of
introducing an alcohol into said extruder barrel during the passing
of said product therethrough.
54. A method of processing a product comprising the steps of:
passing said product in serial order through an extruder and a die
assembly to yield an extruded product, said extruder comprising an
elongated, tubular barrel having an outlet end with at least one
elongated, axially rotatable, helically flighted screw within the
barrel, said die assembly including an elongated, tubular body
operatively coupled to said barrel adjacent the outlet end thereof,
and an apertured die coupled to said body adjacent the end thereof
remote from said extruder, said extruder having a free volume
within said barrel and said die assembly having a free volume
within said tubular body, the volumetric ratio of said die assembly
to said extruder free volume being at least about 2.
55. The method of claim 54, further including the steps of:
agitating said extruded product; and pneumatically passing said
agitated product through a dehydrating tower.
56. The method of claim 55, wherein said agitating step comprises
placing said extruded product into the chamber of a receiver having
an agitator within said chamber, said agitator comprising a
plurality of arms mounted radially on a rotating shaft, each of
said arms including a pair of blades disposed so that the free
edges of said blades form cutting edges directed in the direction
of rotation of said shaft, said shaft being rotated during said
agitating step so that said blades contact said extruded
product.
57. The method of claim 55, wherein said agitating step comprises
contacting air having an impact temperature of from about
300-550.degree. C. with said extruded product.
58. The method of claim 55, wherein said dehydrating tower has a
material outlet and said passing step comprises applying negative
air pressure to said outlet.
59. The method of claim 58, wherein said negative air pressure is
applied by a cyclone separator having a material outlet to create
an air flow through said separator for further drying the product
and for separating said product from said air flow.
60. The method of claim 59, further including the step of passing
said separated product through said cyclone material outlet, and
wherein the amount of time that passes from the beginning of said
agitating step to the time when the product passes through said
cyclone material outlet is less than about 15 seconds.
61. The method of claim 55, wherein the residence time of said
agitated product in the tower is from about 1-2 seconds.
62. The method of claim 55, wherein the product resulting from said
pneumatic passing step has a moisture content of from about 0.5-18%
by weight, based upon the total weight of the product taken as 100%
by weight.
63. The method of claim 55, the retention time of said product in
said extruder being from about 3-20 seconds.
64. The method of claim 55, the retention time of said product in
said die assembly being at least about 15 seconds.
65. The method of claim 55, wherein the maximum temperature within
said extruder is up to about 150.degree. C.
66. The method of claim 55, wherein said product is a
starch-bearing product selected from the group consisting of grain,
root and tuber starches, rice, wheat, oats, barley, corn, rye, and
mixtures thereof.
67. The method of claim 55, further including the step of
subjecting said product to a preconditioning step prior to passage
thereof through said extruder, said preconditioning step including
the steps of adding moisture to the product and heating the
product.
68. The method of claim 55, further including the step of
introducing an alcohol into said extruder barrel during the passing
of said product therethrough.
69. The method of claim 68, wherein said alcohol is ethanol.
70. An extruded starch product having a water solubility of at
least about 10%.
71. The product of claim 70, said starch product being selected
from the group consisting of grain, root and tuber starches and
mixtures thereof, and starch-bearing grain products selected from
the group consisting of rice, wheat, oats, barley, corn, rye, and
mixtures thereof.
72. The method of claim 28, said product selected from the group
consisting of protein-bearing products and nutraceuticals.
73. The method of claim 72, said protein bearing products selected
from the group consisting of vegetable, dairy and meat protein
products.
74. The method of claim 54, said product selected from the group
consisting of protein-bearing products and nutraceuticals.
75. The method of claim 74, said protein bearing products selected
from the group consisting of vegetable, dairy and meat protein
products.
Description
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Nos. 09/135,203 filed Aug. 17, 1998 and 09/249,648
filed Feb. 12, 1999.
FIELD OF THE INVENTION
[0002] The present invention is broadly concerned with low shear
extrusion and drying apparatus and methods of extrusion of various
products such as starches and proteinaceous products. In one aspect
of the invention, methods of forming granular cold water soluble
starch products (which can also be referred to as cold water
swelling products) while producing little or no liquid effluent are
provided. In this way, large quantities of the starch products can
be produced in shorter periods of time compared to prior art
processes. The invention is also directed towards methods of
forming pre-gelled starch products and of processing starch-bearing
materials which normally yield sticky, unworkable products using
little or no surfactant, amylose-complexing agents, or lipids. In
practice, an extruder is coupled with an elongated, tubular die
assembly and processing conditions are selected so as to
substantially cook the starch-bearing materials. This involves
product residence times within the downstream die assembly which
are greatly in excess of extruder residence times. In one
embodiment, as the cooked extrudate emerges from the die assembly,
it is passed through a dehydration assembly which substantially
removes the liquids from the extrudate to yield a dried, solid cold
water soluble starch product.
DESCRIPTION OF THE PRIOR ART
[0003] Starch-bearing materials such as prime starches and
farinaceous grains have long been extrusion processed. For example,
food thickeners can be made by extrusion techniques, although they
generally do not have thickening powers equal to drum dried
starches. Likewise, grains can be extrusion processed to give a
number of useful end products. Generally speaking, extrusion of
starch-bearing products, if not carefully controlled, can lead to
wholly unworkable, sticky extrudates which cannot be properly
sized, shaped or handled. It is known that extrusion processing and
the shear conditions inherent therein tend to degrade the starch
which, in the presence of moisture, leads to stickiness or
functionality problems. It has been determined that shear
conditions are a major contributing factor to the problems with
prior extrusion processing of starches. Excess shear can lead to
starch granule damage, vitamin losses, protein complexing or
degradation, and reduction in molecular weight of biopolymers.
[0004] In order to overcome this issue, it has heretofore been
thought necessary to add appreciable quantities of surfactants such
as monoglycerides or lipids or derivatives thereof to the extrusion
mixture. Although surfactant use can control the stickiness
problem, the added surfactants are relatively expensive and add
significant cost to the final product.
[0005] In the past, instant, non-granular starches have
traditionally been formed using conventional drum-drying
techniques. Generally, these starches have been chemically modified
in order to achieve the desired gelling properties. U.S. Pat. No.
4,465,702 to Eastman et al. discloses a cold water soluble granular
starch derived from chemically unmodified, ungelatinized corn
starch. This starch is prepared by forming a slurry of corn starch
in a liquid processing medium comprising water and alcohol. The
slurry is heated to a temperature of at least 300.degree. F. at or
above autogenic pressure, after which the starch material is
separated from the processing medium. However, the Eastman et al.
process is a batch process, thus preventing large quantities of
cold water soluble starch from being rapidly produced. Furthermore,
the Eastman et al. process produces rather large quantities of
liquid effluent.
[0006] In like manner, extrusion processing of proteinaceous
products and nutraceuticals have presented problems such as protein
complexation or degradation of proteins and vitamins or other
nutraceuticals. Here again, it is believed that high shear
conditions found in many extruders are the chief reasons why
extrusion processing can create problems of these types.
[0007] There is accordingly a need in the art for improved, low
shear extrusion apparatus and corresponding methods which can be
used to process a wide variety of products while minimizing
shear-related problems. For example, there is a need for a process
for continually producing cold water soluble or swellable starches
with little or no liquid effluent and with a minimal amount of
shear.
SUMMARY OF THE INVENTION
[0008] The present invention provides improved extrusion apparatus
and methods which yield improved end products. The invention is
suitable for use in the processing of protein-bearing substances
(e.g., vegetable, dairy or meat protein products) as well as
processing of starch-bearing materials. In the latter case, the
methods hereof product workable, starch-bearing normally sticky
extrudates with little or no surfactant, lipids or derivatives
thereof. Indeed, in preferred forms of this embodiment, the
starch-bearing materials are essentially free of any such added
ingredients. The invention further provides improved methods for
forming pre-gelled starch products. In another embodiment, the
invention provides extrusion and drying apparatus and methods for
forming cold water soluble/swelling/gelling starch products. As
used herein, soluble, swelling, and/or gelling starch refers to a
starch which will form, in the presence of sufficient water and
without additional heating or cooking, a coherent starch mass which
is sliceable and has the appearance of a fully cooked starch gel.
In the case of pre-gelled starches, while they will form a coherent
starch mass in the presence of water without heating or cooking,
some will not be sliceable nor have the appearance of a fully
cooked starch gel.
[0009] Broadly speaking, extrusion cooking apparatus in accordance
with all embodiments of the invention are in the form of an
elongated extruder having a tubular barrel with an outlet end and
at least one (and preferably a pair of) elongated, axially
rotatable, helically flighted screw(s) within the barrel for moving
material therethrough. A tubular die assembly is operatively
coupled to the barrel adjacent the outlet end thereof and includes
an elongated, tubular body with an apertured die secured to the end
of the tubular body remote from the extruder barrel.
[0010] Preferably, the extrusion apparatus is designed so that the
residence or retention time of the product within the die assembly
is greater than the residence time within the extruder. Thus, the
product is subjected to reduced shear during processing so as to
minimize shear-related problems, e.g., the tendency of
starch-bearing materials to become sticky and unworkable. At the
same time, the extrusion conditions should be sufficient to
adequately cook the product, which in the case of starch-bearing
materials generally means that the materials have essentially
completely gelatinized starch fractions (preferably at least about
80% gelatinized, and more preferably at least about 100%
gelatinized). The volumetric ratio of the die assembly to the
extruder free volume should be at least about 2, preferably from
about 3-20, and more preferably from about 3-6.
[0011] When forming cold water soluble starch products, a
dehydrating assembly is preferably positioned adjacent the die for
receiving and at least partially dehydrating an extrudate.
Preferably, the dehydrating assembly comprises an agitator and an
upright dehydrating tower operatively coupled to receive material
from the agitator.
[0012] In accordance with the apparatus and methods of the
invention, cold water soluble and pre-gelled starch products can be
continuously produced. These products can be formed utilizing
starches selected from the group consisting of grain, root and
tuber starches, rice, wheat, oats, barley, corn, rye, and mixtures
thereof; in addition, whole grain products can also be produced
from the foregoing types of starch-bearing grains.
[0013] Cold water soluble starch products in accordance with the
invention have a water solubility of at least about 10%, and
preferably from about 60-70%. As used herein, the cold water
solubility of a starch-containing sample is determined by mixing 1
gram of the sample with 100 ml of distilled water in a Waring
Blender for 15 seconds at low speed and 2 minutes at high speed.
The suspension is then centrifuged at 3100 rpm for 15 minutes and
dried at 110.degree. C. for 4 hours thus evaporating the
supernatant liquid. The residue is then weighed and compared to the
starting weight of the sample to determine the percent of the
sample that was solubilized in the water.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic drawing illustrating the equipment
setup of the extruder, die assembly, and dehydration assembly in
accordance with one embodiment of the invention;
[0015] FIG. 2 is a side view in partial vertical section
illustrating the preferred tubular die assembly;
[0016] FIG. 3 is an Rapid Viscoamylograph (RVA) graph of a
precooked rice analog product in accordance with the invention;
[0017] FIG. 4 is an RVA graph of a precooked no-surfactant
farinaceous cereal product produced in accordance with the
invention (Run #3), as compared with a conventional
surfactant-added cereal product produced by a prior art method (Run
#4); and
[0018] FIG. 5 is an RVA graph of wheat starch produced by the
methods of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] Turning now to the drawings, FIG. 1 illustrates the
equipment setup 10 for producing a starch product in accordance
with the invention. The setup 10 broadly includes an extrusion
assembly 12 and a dehydration assembly 14. Extrusion assembly 12
includes a preconditioner 16, an extruder 18, and an elongated,
tubular die assembly 20 operatively coupled to extruder 18.
Dehydration assembly 14 broadly includes a feed section 22, a
drying section 24, and a vacuum section 26.
[0020] In more detail, the preconditioner 16 of assembly 12 is a
Wenger 2 DDC (Wenger Manufacturing Inc., Sabetha, Kans.) of the
type described in U.S. Pat. No. 4,752,139, which is incorporated by
reference herein. The purpose of preconditioner 16 is to moisten
and initially cook to a limited degree the starting dry
ingredients. Preconditioner 16 includes an inlet 28 and an outlet
portion 30.
[0021] In the embodiment illustrated, the extruder 18 is a 2-headed
Wenger TX57 twin screw extruder having an elongated, sectionalized,
barrel 32 presenting an inlet 34 and an outlet end 36. The barrel
32 is of essentially constant internal diameter and may be provided
with internal flighting or ribs, as is well understood by those
skilled in the art. In addition, barrel 32 is typically provided
with external jackets (not shown) allowing introduction of heat
exchange media (e.g., stearn, water, or oil) for indirect
temperature control of the extruder. In practice, the barrel 32 and
the associated screws may be of conical configuration throughout
all or a portion of their length, or they may be of constant,
non-decreasing diameter. The L/D ratio of the extruder 18 is
defined as the full length of the extruder barrel divided by the
maximum outside diameter presented by the screw element(s). In the
case of the depicted twin screw extruder, the maximum outside
diameter of one of the screw assemblies would be used. Preferably,
the L/D ratio of extruders in accordance with the invention is from
about 5-14, and more preferably from about 6-10. Also, barrel 32
may be equipped with one or more ports for the injection of
additives, such as ethanol, directly into the confines of the
barrel. A drive 38 conventionally composed of a drive motor and
bearing house is operatively coupled to the internal screw
element(s) within barrel 32 for rotating the screw element(s) at
the desired rotational speed. Referring to FIG. 2, the die assembly
20 is made up of an elongated tubular body 40 as well as an
apertured, endmost extrusion die 42. The body 40 includes an inlet
portion 44 of substantially constant internal diameter, as well as
an outlet portion 46 which has a radially enlarged internal
diameter; the body 40 may assume other configurations such as
conical or flared. Multiple process control monitoring devices such
as transducers or thermocouples 48 may be provided in the outlet
portion 46 for process control. The die 42 includes a plurality of
spaced apart, flow-restricting through-apertures 50 for extrusion
of product therethrough. In addition, the die 42 has a
substantially centrally located, inwardly extending, outwardly
tapered flow-directing member or "bullet" 52 affixed thereto. An
elongated, outwardly extending knife shank 54 is also provided.
[0022] In alternate designs, the die spacer 20 could include
internal, static mixing elements which would tend to further mix
the product downstream of the extruder barrel. In addition, a
flighted or other type of extension could be attached to the end of
the extruder screw and extend into the confines of the die assembly
20 to provide such mixing.
[0023] Dehydration assembly 14 is preferably used when preparing
cold water soluble starches and is a KIX Model K-1 dehydrator
(available from Wenger Manufacturing Inc., Sabetha, Kans.) similar
to the type described in U.S. Pat. No. 4,573,278, incorporated by
reference herein. Feed section 22 of assembly 14 includes agitator
56, agitator feed bin 58, and agitator motor 60. Agitator 56
includes at least two sets of arms (each set comprises four arms)
equally disposed in a perpendicular relationship about a vertical
shaft centrally located within the housing of agitator 56 (not
shown). Each arm includes a pair of blades disposed to form a
V-shaped cross-section on the ends, of each arm, with the free
edges of the blades providing sharp cutting edges. This setup
causes the material within agitator 56 to be constantly thrown
around and comminuted by the cutting edges of the blades.
[0024] Section 24 of assembly 14 includes a burner chamber 62, a
connecting duct 64, and a drying tower 66. Chamber 62 includes a
burner (not shown) which may be fed with oil or other suitable fuel
to provide a stream of hot air by means of a blower (not shown) to
agitator 56.
[0025] The tower 66 has an upright vertical shaft and is conical in
shape, with the diameter progressively decreasing as material
travels up the tower. Tower 66 of the preferred dehydrator assembly
14 is a single pass tower without baffles, having a material inlet
at the lower portion thereof operatively coupled to the material
outlet of agitator 56. Tower 66 further includes a material outlet
operatively connected to cyclone 68 via a connecting duct. The
height of tower 66 is preferably from about 8-25 feet, and more
preferably from about 18-22 feet. Those skilled in the art will
appreciate that baffles can be incorporated into the shaft of tower
66 as described in U.S. Pat. No. 4,573,278. Furthermore, a vertical
wall could be incorporated in the shaft of tower 66 in applications
where two passes of the material through the shaft is
necessary.
[0026] Vacuum section 26 includes cyclone 68, cyclone vacuum duct
70, and vacuum fan unit 72. Each of the components of section 26 is
entirely conventional in nature. Cyclone 68 assists in continuing
or creating pneumatic flow through assembly 14 by way of negative
pressure.
[0027] In use, starting ingredients which include a starch are fed
into inlet 28 of preconditioner 16 where the material is then
moisturized and at least partially cooked. Preconditioning is
normally carried out so that the product leaving the preconditioner
has a total moisture content of from about 10-50% by weight, and
more preferably from about 18-35% by weight, based upon the total
weight of the preconditioned mixture taken as 100% by weight. The
residence time in preconditioner 16 is preferably at least about 15
seconds, more preferably from about 15-600 seconds, and more
preferably from about 120-240 seconds. The maximum temperature in
preconditioner 16 should range from about 30-100.degree. C., and
more preferably from about 85-95.degree. C. Although not
specifically illustrated in the drawings, it is contemplated that
use may be made of two serially interconnected preconditioners so
as to achieve an even greater degree of preconditioning of the
starting materials.
[0028] The material leaving preconditioner 16 is then fed directly
into inlet 34 of the twin screw extruder 18 and the screws are
rotated in order to advance the material along the length of barrel
32, thus subjecting the material to increasing temperature and
shear. When preparing a cold water soluble starch, an alcohol
(preferably a C.sub.1-C.sub.4 lower alcohol such as ethanol) is
injected into barrel 32 during passage of the material through
extruder 18. This alcohol injection should be at a rate of from
about 5-100% by weight and preferably from about 10-25% by weight,
based upon the weight of the starch content of the material passing
through the extruder barrel.
[0029] Typical residence times of the material in the extruder
barrel 32 range from about 3-20 seconds, and preferably from about
3-12 seconds. Maximum pressure levels achieved in the extruder
barrel should be from about 50-2000 psi, and more preferably from
about 100-600 psi. The maximum temperature that the material should
achieve in barrel 32 is up to about 150.degree. C., and preferably
from about 60-110.degree. C. Extruder 18 should be operated at
rotation speeds of at least about 300 rpm, and more preferably from
about 400-1500 rpm.
[0030] Upon emergence from extruder 18, the material enters inlet
portion 44 of die assembly 20. The emerging extrudate passes
through body 40 and apertures 50 and can then be dried in the
desired manner. The temperature and pressure conditions within die
assembly 20 should be: temperature, up to about 150.degree. C., and
more preferably from about 85-105.degree. C.; and pressure, from
about 50-2000 psi, and more preferably from about 100-600 psi. Upon
emerging from assembly 20, the extrudate should have a moisture
content of from about 10-70% by weight, and preferably from about
20-50% by weight, based upon the total weight of the extrudate
taken as 100% by weight.
[0031] An important factor in practicing the methods of the
invention is that the extruder 18 and die assembly 20 be sized to
achieve an appropriate die assembly internal volume/extruder free
volume ratio. The free volume of the extruder is calculated as the
total internal volume of barrel 32 minus the volume occupied by the
screw element(s) therein. The internal volume of the die assembly
less any components therein is also determined. Broadly, the die
assembly internal volume/extruder free volume ratio should be at
least about 2, preferably from about 3-20, and more preferably from
about 3-6.
[0032] In addition, the overall apparatus should be configured and
operated in order to establish a retention time ratio of die
assembly retention time to extruder retention time of at least
about 5, and preferably from about 7-15, keeping in mind the
extruder retention times set forth above. This involves
appropriately sizing the extruder and die assembly, and also
operating the extruder to achieve such preferred retention time
ratios. Generally, the retention time of the product within the
extruder is from about 3-20 seconds, whereas the retention time
within the die assembly is at least about 15 seconds, and more
preferably from about 50-600 seconds.
[0033] In some starch processing methods, it is advantageous to dry
the extrudate in dehydration assembly 14 after it emerges from the
die 42. This is particularly desirable when forming a cold water
soluble starch product. In these instances, the extrudate is
deposited into feed bin 58 of dehydration assembly 14. The transfer
of extrudate from bin 58 to agitator 56 is carried out via a
motor-driven screw conveyor (not shown) through a gate. The gate is
controlled by means of a solenoid which detects the load on the
agitator 56. The gate is then opened to add more material to
agitator 56, thus controlling and maintaining a constant supply of
the extrudate within agitator 56. Within the housing of agitator
56, the blade-equipped arms are continually rotated, thus
continually throwing and comminuting the extrudate. At the same
time, hot air is supplied to agitator 56 from burning chamber 62 by
way of duct 64. This impact hot air entering the agitator 56 should
have a temperature of from about 300-550.degree. C., and preferably
from about 350-450.degree. C. As the extrudate is comminuted and
dried within agitator 56, its density falls until it reaches such a
level that the pressure within tower 66 allows the material to rise
with the flow of hot air from agitator 56 into tower 66. Air flow
and entrained dehydrated material passes upwardly through the shaft
and outlet of tower 66 under negative air pressure to cyclone 68 by
way of a connecting duct (not shown). The entraining or process air
should have a temperature of from about 90-180.degree. C., and more
preferably from about 130-160.degree. C. The residence time of the
material within tower 66 is preferably about 1-2 seconds.
[0034] Once in cyclone 68, the dried solids are removed from the
cyclone at an airlock (not shown), while saturated air passes from
cyclone 68 through duct 70 to the fan unit 72 where it is then
discharged into the atmosphere. The dried solids should have a
moisture content of from about 0.5-18% by weight, and preferably
from about 6-12% by weight, based upon the total weight of the
dried solids taken as 100% by weight.
[0035] It is preferred that the time required for the extrudate
material to enter agitator 56, pass through the remainder of
dehydration assembly 14, and exit the airlock be no more than about
15 seconds, and preferably from about 5-8 seconds.
[0036] Where proteinaceous or nutraceutical-containing products are
to be processed, generally the dehydration assembly 14 is omitted,
but the extrusion assembly 12 of FIG. 1 is employed. In processing
of such alternate products, the same preconditioning and extruder
parameters of moisture contents, residence times, temperatures,
pressures, die assembly internal volume/extruder free volume
ratios, and retention time ratios of die assembly retention times
to extruder retention times set forth above are applicable.
[0037] The following examples set forth preferred extrusion
apparatus and methods in accordance with the invention. It is to be
understood that the invention is not so limited and nothing in the
examples should be taken as a limitation upon the overall scope of
the invention.
EXAMPLE 1
[0038] In this example, a short length to diameter Wenger TX-57
extruder in combination with an elongated, tubular die extension
was employed for the production of precooked rice analog
products.
[0039] The extruder was of the type depicted in FIG. 1, and
consisted of two heads. In particular, the extruder configuration
was made up of the following components (where all parts are
identified with Wenger Mfg. Co. part numbers): extruder
barrel--55618-001 (inlet head) and 55619-001 (head No. 2). The
screw assembly included the following rotating elements: Screw No.
1-55657-003, 55657-003, 55625-003, 55626-103 and 55621-005; Screw
No, 2-55657-203, 55657-203B,55625-003, 55626-103 and 55621-005. The
tubular die for Run #1 was made up of: 55661-023, 56369-001,
55376-001, and 74010-513. For Run #2, the tubular die consisted of
55661-023, 56369-001, 55376-001, 55376-001, and 74010-513. A
rotating knife assembly was positioned adjacent the outlet of the
die for cutting the extrudate into a convenient size. The knife
assembly included the following: 55226-003 (knife holder) and two
knife blades (19272-027).
[0040] The preconditioner used in both of these setups was a Wenger
Model 2 DDC preconditioner having Configuration No. 380 with the
left shaft equipped with (from inlet to discharge) eighteen
75.degree. forward position beaters, twenty-four 90.degree. neutral
position beaters and eighteen -75.degree. reverse position beaters;
the right shaft had four 75.degree. forward position beaters and
fifty-six -75.degree. reverse position beaters.
[0041] In Run #1, the starting recipe was 100% by weight RL-100
rice flour. In Run #2, the recipe consisted of 96.75% by weight
RL-100 rice flour, 2.50% by weight vegetable oil and 0.75% by
weight Myvaplex surfactant. In each case, the starting material was
fed into and through the preconditioner for moisturizing and
partial cooking thereof, followed by passage through the two head
extruder and associated tubular die structure. Subsequent to
extrusion, the product was conventionally dried to a moisture
content of about 9% by weight.
[0042] The following table sets forth the operating conditions for
the preconditioner and extruder devices in the two runs.
1 TABLE 1 Run #1 Run #2 RAW MATERIAL INFORMATION Dry Recipe Density
kg/m.sup.3 783 -- Dry Recipe Rate kg/hr 126 147 Feed Screw Speed
rpm 22 21 PRECONDITIONING INFORMATION Preconditioner Speed rpm 300
300 Steam Flow to Preconditioner kg/hr 18 17 Water Flow to
Preconditioner kg/hr 29 30 Preconditioner Discharge Temperature
.degree. C. 85 84 Moisture Entering Extruder % wb 31.78 33.17
EXTRUSION INFORMATION Extruder Shaft Speed rpm 500 500 Motor Load %
22 19 Control/Temperature-1st Head .degree. C. 50/55 50/56
Control/Temperature-2nd Head .degree. C. 100/105 100/103
Head/Pressure kPa 2/2770 2/2550 Knife Drive Speed rpm 918 932 FINAL
PRODUCT INFORMATION Extruder Discharge Moisture % wb 25.04 28.12
Extruder Performance Stable Stable
[0043] The post-extrusion drying was carried out in a
multiple-stage dryer under the following conditions: zone 1
temperature, 65.degree. C., zone 2 temperature, 70.degree. C., zone
3 temperature, 69.degree. C., retention time pass 1, 8.7 minutes,
and retention pass 2, 11.5 minutes.
[0044] The straight rice flour run (No. 1) yielded a well-cooked
product with little or no sticking off the die. The product
rehydrated well (although the product was somewhat sticky) and had
a good flavor. In Run #2, an additional spacer was added and this
gave an improved cook. FIG. 3 is a graph illustrating an RVA
analysis of the product from Run #1. This analysis was carried out
using a Series 4 Rapid Visco Analyzer sold by Newport Scientific
Pty. Ltd., Warriewood, NSW, Australia. In such tests, four grams of
the product (dry matter basis) are mixed in 25 ml water and passed
through the Rapid Visco Analyzer using the manufacturer's
protocol.
EXAMPLE 2
[0045] In this example, a pre-cooked farinaceous cereal was
produced using an extruder/tubular die arrangement of the type
illustrated in FIGS. 1-2 (Run #3) with an extruder L/D ratio of
7.5, and this product was compared with a conventional product (Run
#4) made using a nine head extruder setup (L./D ratio of 25.5:1) of
the type illustrated in U.S. Pat. No. 4,769,251, incorporated by
reference herein, as well as the cooking procedure described in
that patent.
[0046] The Run #3 extruder consisted of two heads. In particular,
the extruder configuration was made up of the following components
(where all parts are identified with Wenger Mfg. Co. part numbers):
extruder barrel--55618-001 (inlet head) and 55619-001 (head No. 2).
The screw assembly included the following rotating elements: Screw
No. 1--55657-003, 55657-003, 55657-103, 55625-003, and 55621-005;
Screw No, 2--55657-003, 55657-003, 55625-003, 55625-003 and
55621-005. The tubular die was made up of: 55661-021, 55369-001,
55376-001, 55376-001, and 74010-745. A rotating knife assembly was
positioned adjacent the outlet of the die for cutting the extrudate
into a convenient size. The knife assembly included the following:
55226-001 (knife holder) and two knife blades (19273-001).
[0047] The preconditioner used in Run #3 was a Wenger Model 2 DDC
preconditioner having Configuration No. 109.
[0048] In Run #3, the starting recipe consisted of 100% by weight
of maize meal. In Run #4, the recipe consisted of 99.25% by weight
maize meal and 0.75% by weight Dimodan PV surfactant. In each case,
the starting material was fed into and through the preconditioner
for moisturizing and partial cooking thereof, followed by passage
through the associated extruder; in the case of Run #3, the
material was then passed through the tubular die structure. In Run
#4, a small die arrangement was employed, having a small ratio of
die spacer volume to extruder free volume. Subsequent to extrusion,
the product was conventionally dried to a moisture content of about
16% by weight.
[0049] The following table sets forth the operating conditions for
the preconditioner and extruder devices in Run #3.
2 TABLE 2 Run #3 RAW MATERIAL INFORMATION Dry Recipe Density
kg/m.sup.3 626 Dry Recipe Rate kg/hr 126 Feed Screw Speed rpm 35
PRECONDITIONING INFORMATION Preconditioner Speed rpm 300 Steam Flow
to Preconditioner kg/hr 17 Water Flow to Preconditioner kg/hr 29
Preconditioner Discharge Temperature .degree. C. 79 Moisture
Entering Extruder % wb 34.59 EXTRUSION INFORMATION Extruder Shaft
Speed rpm 500 Motor Load % 14 Control/Temperature-1st Head .degree.
C. 35/59 Control/Temperature-2nd Head .degree. C. 77/81
Head/Pressure kPa 2/299 Knife Drive Speed rpm 2148 FINAL PRODUCT
INFORMATION Extruder Discharge Moisture % wb 31.38 Extruder
Performance Stable
[0050] The post-extrusion drying was carried out in a
multiple-stage dryer under the following conditions: zone 1
temperature, 65.degree. C., zone 2 temperature, 65.degree. C., zone
3 temperature, 67.degree. C., retention time pass 1, 8.6 minutes,
and retention pass 2, 11.4 minutes.
[0051] The precooked cereal product made using the extruder device
of the invention without surfactant was at least equivalent to the
surfactant-added product of Run #4. As shown in FIG. 4, the RVA
analysis of Runs #3 and 4 were virtually identical.
EXAMPLE 3
[0052] In this example, a short length to diameter Wenger TX-57
extruder in combination with an elongated, tubular die extension
was employed for the production of cooked starch products.
[0053] The extruder consisted of two heads. In particular, the
extruder configuration was made up of the following components
(where all parts are identified with Wenger Mfg. Co. part numbers):
extruder barrel--55618-001 (inlet head) and 55619-001 (head No. 2).
The screw assembly included the following rotating elements: Screw
No. 1--55657-003, 55657-003, 55626-103, 55626-103 and 55624-201F
and 55621-004; Screw No, 2--55657-003, 55657-003B, 55626-103,
55626-103, 55624-201F, and 55621-005. The tubular die was made up
of: 55376-001, 55376-002, 55662-001 and 74010-745 (with 12 of the
24 holes plugged). A rotating knife assembly was positioned
adjacent the outlet of the die for cutting the extrudate into a
convenient size. The preconditioner used in both of these setups
was a Wenger Model 2 DDC preconditioner having Configuration No.
109 with the left shaft equipped with (from inlet to discharge)
eighteen 75.degree. forward position beaters, twenty-four
90.degree. neutral position beaters and eighteen -75.degree.
reverse position beaters; the right shaft had eighteen 75.degree.
forward position beaters, twenty-four 90.degree. neutral position
beaters and eighteen -75.degree. reverse position beaters.
[0054] In Runs #5-7, the starting recipe was, respectively, 100% by
weight wheat starch, corn starch, and potato starch. In each case,
the starting material was fed into and through the preconditioner
for moisturizing and partial cooking thereof, followed by passage
through the two head extruder and associated tubular die structure.
Also, 95% ethanol was injected into the extruder barrel during each
of the runs. Ethanol (or other appropriate C.sub.1-C.sub.4 lower
alcohol) assists in obtaining higher viscosity starch products, as
it prevents starch damage during extrusion processing. Subsequent
to extrusion, the product was conventionally dried to a moisture
content of about 9% by weight.
[0055] The following table sets forth the operating conditions for
the preconditioner and extruder devices in the two runs.
3 TABLE 3 Run #5 Run #6 Run #7 RAW MATERIAL INFORMATION Dry Recipe
Density kg/m.sup.3 577 670 695 Dry Recipe Rate kg/hr 90 95 95 Feed
Screw Speed rpm 18 21 18 PRECONDITIONING INFORMATION Preconditioner
Speed rpm 300 300 300 Steam Flow to Preconditioner kg/hr 12 12 8
Water Flow to Preconditioner kg/hr 16 16 16 Preconditioner
Discharge .degree. C. 74 77 76 Temperature Moisture Entering
Extruder % wb 34.46 -- 34.60 EXTRUSION INFORMATION Extruder Shaft
Speed rpm 444 444 494 Motor Load % 15 12 7 Water Flow to Extruder
kg/hr 4 4 4 Extruder Additive (Ethanol) kg/hr 18 18 18 Rate
Control/Temperature- .degree. C. 24/45 24/49 24/39 1st Head
Control/Temperature- .degree. C. 51/50 51/50 51/53 2nd Head
Head/Pressure kPa 2/1310 2/1010 2/340 FINAL PRODUCT INFORMATION
Extruder Discharge Moisture % wb 34.87 -- 42.64 Extruder
Performance Stable Stable Stable
[0056] The post-extrusion drying was carried out in a
multiple-stage dryer using conventional conditions. FIG. 5
illustrates the RVA analysis obtained with the product from Run
#5.
EXAMPLE 4
[0057] In these runs, either a starch or a flour was fed to a
Wenger TX57 twin screw extruder equipped with a preconditioner and
an auger feed hopper and processed to obtain a cooked pre-gelled
starch product. The preconditioner used was a Model 2DDC,
configuration No. 109, having a total of 60 shaft-mounted beaters.
The TX57 configuration included the following Wenger parts: head 1,
55618-001 and head 2, 55619-001. The device also included rotating
elements from inlet to outlet, 55657-003, 55657-003 B, 55626-103,
55626-103, 55624-201 F, and 55621-005 on the left shaft, and
rotating elements from inlet to outlet 55657-203, 55657-203,
55626-103, 55626-1Q3, 55624-201 F, and 55621-005 on the right
shaft. The extruder had a tubular die/adapter assembly coupled to
the outlet end of the barrel made up of Wenger Parts No. 55367-001
AC, 55376-002 NA, 55662-001 AD, and 74010-745 NA. The die
corresponding to Wenger Part No. 74010-745 included twenty-four
holes with twelve of the holes blocked.
[0058] In carrying out the runs described below, the starting
ingredient (either starch or flour) was fed into the preconditioner
along with steam and water to premoisten and partially precook the
ingredients. After preconditioning, the material was fed into the
extruder barrel where the material was subjected to increasing
temperatures, pressure, and shear. In addition, water was fed into
the interior of the extruder barrel during passage of the
ingredients therethrough. The jacketed heads were provided with
circulating heating media. The resulting extrudate was dried in
ambient air.
[0059] The recipes used are set forth in Table 4A. Tables 4B and 4C
set forth the results of these production runs.
4TABLE 4A RECIPE NO. INGREDIENT 1 100% wheat starch 2 100% corn
starch 3 100% tapioca starch 4 100% potato starch 5 100% wheat
flour
[0060]
5 TABLE 4B Run Run Run Run #8 #9 #10 #11 DRY RECIPE INFORMATION Dry
Recipe % wb 9.23 9.23 9.23 9.23 Moisture Dry Recipe kg/m.sup.3 577
577 577 577 Density Dry Recipe Rate kg/hr 100 100 100 110 Feed
Screw rpm 20 18 19 17 Speed PRE- CONDITIONING INFORMATION
Preconditioner rpm 300 300 300 300 Speed Steam Flow kg/hr 12 12 12
12 to Preconditioner Water Flow kg/hr 16 8 8 8 to Preconditioner
Preconditioner kg/hr -- 9 18 18 Additive 1 Rate Preconditioner
.degree. C. 85 77 70 69 Discharge Temperature Moisture % wb 25.91
29.3 29.15 29.26 Entering Extruder EXTRUSION INFORMATION Extruder
Shaft rpm 444 444 444 444 Speed Extruder Motor % 13 12 11 15 Load
Water Flow to kg/hr 15 15 15 -- Extruder Control/ .degree. C. 24/37
24/48 24/49 24/46 Temperature 1st Head Control/ .degree. C. 51/52
51/51 51/51 51/54 Temperature 2nd Head Head/Pressure kPa 2/990
2/1140 2/1280 2/2100 FINAL PRODUCT INFORMATION Extruder % wb 36.54
35.12 35.07 30.72 Discharge Moisture Extruder Stable Stable Stable
Stable Performance Recipe Number 1 1 1 1 Run Rating Good Good Good
Good
[0061]
6 TABLE 4C Run Run Run Run #12 #13 #14 #15 DRY RECIPE INFORMATION
Dry Recipe Moisture % wb 11.22 12.64 -- 14.04 Dry Recipe Density
kg/m.sup.3 670 517 695 652 Dry Recipe Rate kg/hr 100 100 104 103
Feed Screw Speed rpm 19 24 18 15 PRECONDITIONING INFORMATION
Preconditioner Speed rpm 300 300 300 300 Steam Flow to kg/hr 12 8 8
8 Preconditioner Water Flow to kg/hr 16 16 16 16 Preconditioner
Preconditioner Additive kg/hr -- -- -- -- 1 Rate Preconditioner
Discharge .degree. C. 76 74 77 75 Temperature Moisture Entering %
wb -- 31.77 -- 33.72 Extruder EXTRUSION INFORMATION Extruder Shaft
Speed rpm 463 449 497 496 Extruder Motor Load % 10 12 9 8 Water
Flow to Extruder kg/hr 15 15 15 15 Control/Temperature .degree. C.
24/50 24/39 24/41 24/43 1st Head Control/Temperature .degree. C.
51/53 51/52 51/51 51/50 2nd Head Head/Pressure kPa 2/330 2/900
2/360 2/160 FINAL PRODUCT INFORMATION Extruder Discharge % wb 38.38
38.94 44.55 39.88 Moisture Extruder Performance Stable Stable
Stable Stable Recipe Number 2 3 4 5 Run Rating Good Good Good
Good
[0062] In Run #8, the extrudate strands were slightly sticky and
some uncooked starch (white spots) was visible. In Run #9, the
final extrudate also included uncooked starch. The extrudate of Run
#10 had a smooth glassy appearance and was clear with white spots
visible, indicating uncooked starch. The product of Run #11 was
beginning to expand, and white spots and bubbles were visible.
[0063] Run #13 utilized tapioca starch and the resulting product
was very sticky and white and had a bumpy surface. Run #14 utilized
potato starch and the resulting product had a cloudy, white
appearance and was very sticky. In Run #15, wheat flour was the
starting ingredient and the resulting product had a cloudy,
yellow-white appearance and was slightly sticky off the die.
EXAMPLE 5
[0064] In this run, 100% wheat starch was fed to a Wenger TX57 twin
screw extruder equipped with a preconditioner and an auger feed
hopper and processed to obtain a cooked product. The preconditioner
used was a Model 2DDC, configuration No. 109, having a total of 60
shaft-mounted beaters. The TX57 machine was of the type used in the
previous examples, and the configuration included the following
Wenger parts: head 1, 55618-001 and head 2, 55619-001. The device
also included rotating elements from inlet to outlet, 55657-0Q3,
55657-003 B, 55626-103, 55626-103, 55624-201 F, and 55621-005 on
the left shaft, and rotating elements from inlet to outlet
55657-203, 55657-203, 55626-103, 55626-103, 55624-201 F, and
55621-005 on the right shaft. The extruder had a tubular
die/adapter assembly coupled to the outlet end of the barrel made
up of Wenger Parts No. 55662-001 AD, 55376-001 AC, 55376-001 AC,
and 74010-745 NA. The extruder was equipped with two knife blades,
Wenger Part No. 19272-027 in conjunction with a knife holder,
Wenger Part No. 55226-001. In carrying out the runs described
below, 100% wheat starch was fed into the preconditioner along with
steam and water to premoisten and partially precook the
ingredients. After preconditioning, the material was fed into the
extruder barrel where the material was subjected to increasing
temperatures, pressure, and shear. In addition, water was fed into
the interior of the extruder barrel during passage of the
ingredients therethrough. The jacketed heads were provided with
circulating heating media. The extrudate was dried in ambient
air.
[0065] Table 5 sets forth the results of this production run.
7 TABLE 5 Run #16 DRY RECIPE INFORMATION Dry Recipe Moisture % wb
11.82 Dry Recipe Density kg/m.sup.3 -- Dry Recipe Rate kg/hr 97
Feed Screw Speed rpm 37 PRECONDITIONING INFORMATION Preconditioner
Speed rpm 199 Steam Flow to Preconditioner kg/hr 11 Water Flow to
Preconditioner kg/hr 19 Preconditioner Discharge Temperature
.degree. C. 88 Moisture Entering Extruder % wb 32.65 EXTRUSION
INFORMATION Extruder Shaft Speed rpm 498 Extruder Motor Load % 16
Water Flow to Extruder kg/hr 5 Control/Temperature 1st Head
.degree. C. 50/51 Control/Temperature 2nd Head .degree. C. 80/75
Head/Pressure kPa 2/1380 Knife Drive Speed rpm 315 DRYER
INFORMATION Zone 1 Temperature .degree. C. 24 Zone 2 Temperature
.degree. C. 24 Zone 3 Temperature .degree. C. 24 Retention Time -
Pass 1 min. 0.9 Retention Time - Pass 2 min. 1.4 Fan Speed 1 rpm
1406 Fan Speed 2 rpm 1406 Fan Speed 3 rpm 1406 FINAL PRODUCT
INFORMATION Extruder Discharge Moisture % wb 29.77 Extruder
Discharge Density kg/m.sup.3 615 Extruder Performance Stable Run
Rating Good
[0066] The product of this run had a translucent appearance and was
completely cooked and cuttable, yielding a quality pre-gelled
starch product.
EXAMPLE 6
[0067] In these runs, the same equipment was used as described in
Example 4 with the following exceptions: the extruder was equipped
with two knife blades, Wenger Part No. 19272-027 in conjunction
with a knife holder, Wenger Part No. 55226-001; in Run #17, the
tubular die assembly coupled to the outlet end of the barrel was
made up of Wenger Part Nos. 55662-001 AD, 55376-001 AC, 55376-001
AC, and 74010-745 NA; and in Run #18, the tubular die assembly
coupled to the outlet end of the barrel was made up of Wenger Part
Nos. 55662-001 AD, 55376-001 AC, 55376-002 NA, and 74010-745 NA. In
both runs, the die corresponding to Part No. 74010-745 contained 24
holes, with 12 holes having short land length and being
plugged.
[0068] In both runs, the procedures followed were the same as
described previously in Examples 4-5, with 100% wheat starch being
used in Run #17, and 100% corn starch being used in Run #18. Table
6 sets forth the results of these production runs.
8 TABLE 6 Run #17 Run #18 DRY RECIPE INFORMATION Dry Recipe
Moisture % wb 12.16 8.08 Dry Recipe Density kg/m.sup.3 545 669 Dry
Recipe Rate kg/hr 100 96 Feed Screw Speed rpm 44 36 PRECONDITIONING
INFORMATION Preconditioner Speed rpm 200 300 Steam Flow to
Preconditioner kg/hr 11 11 Water Flow to Preconditioner kg/hr 19 21
Preconditioner Discharge Temperature .degree. C. 85 86 Moisture
Entering Extruder % wb 28.65 24.32 EXTRUSION INFORMATION Extruder
Shaft Speed rpm 499 449 Extruder Motor Load % 14 11 Water Flow to
Extruder kg/hr 5 10 Control/Temperature 1st Head .degree. C. 50/51
50/60 Control/Temperature 2nd Head .degree. C. 80/74 80/76
Head/Pressure kPa 2/0 2/5920 Knife Drive Speed rpm 770 1494 DRYER
INFORMATION Zone 1 Temperature .degree. C. 25 24 Zone 2 Temperature
.degree. C. 25 24 Zone 3 Temperature .degree. C. 25 24 Retention
Time - Pass 1 min. 2 0.9 Retention Time - Pass 2 min. 2 1.3 Fan
Speed 1 rpm -- 1406 Fan Speed 2 rpm -- 1406 Fan Speed 3 rpm -- 1406
FINAL PRODUCT INFORMATION Extruder Discharge Moisture % wb 32 24.81
Extruder Discharge Density kg/m.sup.3 705 714 Extruder Performance
Stable Stable Duration of Run min. 30 20 Run Rating Good Good In
Run #17, the extrudate was clear in color and very translucent.
EXAMPLE 7
[0069] In these runs, either a starch or flour was fed to a Wenger
TX57 twin screw extruder equipped with an elongated, tubular die
extension and a preconditioner (as shown in FIG. 1) and processed
to obtain a cold water soluble starch product. The preconditioner
used was a Model 2DDC, configuration No. 109, having a total of 60
shaft-mounted beaters with the left shaft equipped with (from inlet
to discharge) eighteen 75.degree. forward position beaters,
twenty-four 90.degree. neutral position beaters, and eighteen
-75.degree. reverse position beaters; the right shaft had eighteen
75.degree. forward position beaters, twenty-four 90.degree. neutral
position beaters, and eighteen -75.degree. reverse position
beaters. The TX57 machine was of the type illustrated in U.S. Pat.
No. 4,875,847, incorporated by reference herein. The TX57 equipment
is commercialized by Wenger Manufacturing of Sabetha, Kans., and
the configuration included the following Wenger parts: head 1,
55618-001 and head 2, 55619-001. The device also included rotating
elements from inlet to outlet, 55657-003, 55657-003 B, 55626-103,
55626-103, 55624-201 F, and 55621-005 on the left shaft, and
rotating elements from inlet to outlet 55657-203, 55657-203,
55626-103, 55626-103, 55624-201 F, and 55621-005 on the right
shaft. The tubular die assembly coupled to the outlet end of the
barrel was made up of Wenger Parts No. 55367-001 AC, 55376-002 NA,
55662-001 AD, and 74010-745 NA. The die corresponding to Wenger
Part No. 74010-745 included twenty-four holes with twelve of the
holes blocked.
[0070] In carrying out the runs described below, the starting
ingredient (either starch or flour) was fed into the preconditioner
along with steam and water to premoisten and partially precook the
ingredients. After preconditioning, the material was fed into the
extruder barrel where the material was subjected to increasing
temperatures, pressure, and shear. In addition, water and 190 proof
ethanol was fed into the interior of the extruder barrel during
passage of the ingredients therethrough. The jacketed heads were
provided with circulating heating media. The resulting extrudate
was dried in ambient air.
[0071] The recipes used are set forth in Table 7A. Table 7B sets
forth the results of these production runs.
9TABLE 7A RECIPE NO. INGREDIENT 1 100% wheat starch 2 100% corn
starch 3 100% tapioca starch 4 100% potato starch 5 100% wheat
flour
[0072]
10 TABLE 7B Run Run Run Run Run #19 #20 #21 #22 #23 DRY RECIPE
INFOR- MATION Dry % wb 9.23 11.22 12.62 -- 14.04 Recipe Moisture
Dry kg/m.sup.3 577 670 517 695 652 Recipe Density Dry kg/hr 90 95
100 95 98 Recipe Rate Feed rpm 18 21 23 18 15 Screw Speed PRE-
CONDI- TION- ING INFOR- MATION Precondi- rpm 300 300 300 300 300
tioner Speed Steam kg/hr 12 12 8 8 12 Flow to Precondi- tioner
Water kg/hr 16 16 16 16 16 Flow to Precondi- tioner Precondi- kg/hr
-- -- -- -- -- tioner Additive 1 Rate Precondi- .degree. C. 74 77
77 76 76 tioner Discharge Tempera- ture Moisture % wb 34.46 --
29.59 34.6 30.88 Entering Extruder EXTRU- SION INFOR- MATION
Extruder rpm 444 444 444 494 444 Shaft Speed Extruder % 15 12 9 7 6
Motor Load Water kg/hr 4 4 4 4 4 Flow to Extruder Extruder kg/hr 18
18 18 18 18 Additive Rate Control/ .degree. C. 24/45 24/49 24/40
24/39 24/47 Tempera- ture 1st Head Control/ .degree. C. 51/50 51/51
51/51 51/53 51/51 Tempera- ture 2nd Head Head/ kPa 2/1310 2/1010
2/960 2/340 2/0 Pressure FINAL PROD- UCT INFOR- MATION Extruder %
wb 34.87 -- 37.54 42.64 41.25 Discharge Moisture Extruder Stable
Stable Stable Stable Stable Perform- ance Recipe 1 2 3 4 5 Number
Run Good Good Good Good Good Rating
[0073] In Run #19, the extrudate had a rough, bubbly texture, was
not very sticky, and was very uniform. No spots were visible in the
product and the product. Run #20 (which utilized corn starch
instead of wheat starch and included 18 kg/hr of ethanol added to
the extruder barrel during extrusion) resulted in a smooth,
translucent, yellow-white product having no visible spots. In Run
#21, ethanol was also added to the extruder barrel during extrusion
at a rate of 18 kg/hr resulting in a clear, bubbly product which
did not contain white spots. The product from Run #22 had a uniform
texture and a clear, smooth surface. The extrudate of Run #23 did
not contain white spots, but was sticky off the die.
EXAMPLE 8
[0074] In these runs, 100% wheat starch (Midsol 50) or corn starch
was fed to a Wenger TX57 twin screw extruder equipped with a
preconditioner and an auger feed hopper and processed to obtain a
cooked product. The preconditioner used was a Model 2DDC,
configuration No. 109, having a total of 60 shaft-mounted beaters
and having the beaters positioned in each shaft as described in
Example 7. The TX57 machine was of the type used in Example 7 and
the configuration included the following Wenger parts: head 1,
55618-001 and head 2, 55619-001. The device also included rotating
elements from inlet to outlet, 55657-003, 55657-003 B, 55626-103,
55626-103, 55624-201 F, and 55621-005 on the left shaft, and
rotating elements from inlet to outlet 55657-203, 55657-203,
55626-103, 55626-103, 55624-201 F, and 55621-005 on the right
shaft.
[0075] In Runs #24 and 25, the tubular die assembly coupled to the
outlet end of the barrel made up of Wenger Parts No. 55662-001 AD,
55376-001 AC, 55376-002 NA, and 74010-745 NA. The die corresponding
to part No. 74010-745 contained 24 holes, with 12 holes having
short land length and being plugged. Also in Runs #24 and 25, the
extruder was equipped with two knife blades, Wenger Part No.
19272-027 in conjunction with a knife holder, Wenger Part No.
55226-001.
[0076] In Run #26, the tubular die assembly coupled to the outlet
end of the barrel was made up of Wenger Part Nos. 55662-001 AD,
55376-001 AC, and 55376-002 NA.
[0077] In carrying out the runs described below, 100% wheat starch
or 100% corn starch was fed into the preconditioner along with
steam and water to premoisten and partially precook the
ingredients. After preconditioning, the material was fed into the
extruder barrel where the material was subjected to increasing
temperatures, pressure, and shear. In each of the runs, 190 proof
ethanol was used as the extruder additive and was pumped into head
1, position 1. In addition, water was fed into the interior of the
extruder barrel during passage of the ingredients therethrough. The
jacketed heads were provided with circulating heating media. The
L/D ratio of the extruder was 7.5:1. The extrudate was immediately
passed through a three zone dryer. The product was then dried in a
Wenger-Kix Flash Dryer (Wenger Manufacturing, Sabetha, Kans.) at
process air temperatures of 100.degree. C., 120.degree. C., or
140.degree. C. The product samples were dried at the respective
temperatures for a period of about 2-3 seconds. The remaining
Wenger Kix Flash Dryer parameters are set forth in Table 8A. Table
8B sets forth the ingredients which correspond to the particular
recipe numbers, and Table 8C sets forth the results of these
production runs.
11 TABLE 8A PARAMETER FLASH DRYER SETTING Flameback Temperature
30.degree. C. Impact Temperature 380.degree. C. Infeed Setting 2.0
on dial Agitator Amps 7-18 amps Cyclone Vacuum 1.9 Slide Gate 1.5
inches from open
[0078]
12TABLE 8B RECIPE NO. INGREDIENT 1 100% wheat starch (Midsol 50) 2
100% corn starch
[0079]
13 TABLE 8C Run #24 Run #25 Run #26 DRY RECIPE INFORMATION Dry
Recipe Moisture % wb 21.71 12.14 -- Dry Recipe Density kg/m.sup.3
529 625 625 Feed Screw Speed rpm 21 21 21 PRECONDITIONING
INFORMATION Preconditioner Speed rpm 300 300 300 Steam Flow to
Preconditioner kg/hr 12 12 12 Water Flow to Preconditioner kg/hr 16
16 15 Preconditioner Discharge Temperature .degree. C. 86 89 87
Moisture Entering Extruder % wb 34.46 26.71 23.87 EXTRUSION
INFORMATION Extruder Shaft Speed rpm 449 448 448 Extruder Motor
Load % 16 22 11 Water Flow to Extruder kg/hr 5 -- -- Extruder
Additive Rate kg/hr 18 18 24 Control/Temperature 1st Head .degree.
C. /50 /55 /51 Control/Temperature 2nd Head .degree. C. 51/54 51/51
51/51 Head/Pressure kPa 2/1030 2/1030 2/690 Knife Drive Speed rpm
1100 1367 -- DRYER INFORMATION Zone 1 Temperature .degree. C. 27 --
-- Zone 2 Temperature .degree. C. 28 -- -- Zone 3 Temperature
.degree. C. 29 -- -- Retention Time - Pass 1 min. 2 -- -- Retention
Time - Pass 2 min. 2.4 -- -- Fan Speed 1 rpm 1406 -- -- Fan Speed 2
rpm 1406 -- -- Fan Speed 3 rpm 1406 -- -- FINAL PRODUCT INFORMATION
Extruder Discharge Moisture % wb 36.82 29.45 35.37 Extruder
Discharge Rate kg/hr 79 152 -- Extruder Discharge Density
kg/m.sup.3 719 775 -- Extruder Performance Stable Stable Stable
Recipe Number 1 2 2 Run Rating Good Good Good
[0080] The products of these runs had a translucent appearance. The
samples dried at process air temperatures of 140.degree. C.
rehydrated the fastest and had the highest viscosity when compared
to the samples dried at process air temperatures of 100.degree. C.
and 120.degree. C.
EXAMPLE 9
[0081] A sample of cold water soluble starch prepared in Run #24 of
Example 8 was analyzed with x-ray diffraction. The patterns were
recorded with K.alpha. radiation. The operating parameters were 35
kV at 20 mA with a scanning speed of 2.degree. 2.theta./min., so 10
mm on the chart equals 1.degree. 2.theta.. The sample gave a strong
V-pattern with reflections at 2.theta.=13.7.degree. (d=6.5 .ANG.)
and 2.theta.=20.9.degree. (d=4.3.ANG.). There was a weak reflection
at 2.theta.=8.0.degree. (d=11 .ANG.). This data indicated that the
process changed the native A-type wheat starch to the V-type
starch. The A-polymorph is insoluble in water at 25.degree. C.,
while the V-polymorph swells and is partially soluble.
EXAMPLE 10
[0082] In these runs, the same equipment was used as described in
Example 7 with the following exceptions: the extruder was equipped
with two knife blades, Wenger Part No. 19272-027 in conjunction
with a knife holder, Wenger Part No. 55226-001; in Run #27, the
tubular die assembly coupled to the outlet end of the barrel was
made up of Wenger Part Nos. 55662-001 AD, 55376-001 AC, 55376-001
AC, and 74010-745 NA; and in Run #28, the tubular die assembly
coupled to the outlet end of the barrel was made up of Wenger Part
Nos. 55662-001 AD, 55376-001 AC, 55376-002 NA, and 74010-745 NA. In
both of the runs, the die corresponding to Part No.74010-745
contained 24 holes, with 12 holes having short land length and
being plugged.
[0083] In both runs, the extrusion procedures followed were the
same as described previously with respect to Examples 7-9, with
100% wheat starch being used in Run #27, and 100% corn starch being
used in Run #28. After extrusion, the product was dried in a flash
dryer as described in Example 8. Table 9 sets forth the results of
these production runs.
14 TABLE 9 Run Run #27 #28 DRY RECIPE INFORMATION Dry Recipe
Moisture % wb 12.15 8.08 Dry Recipe Density kg/m.sup.3 545 669 Dry
Recipe Rate kg/hr 99 94 Feed Screw Speed rpm 39 30 PRECONDITIONING
INFORMATION Preconditioner Speed rpm 200 200 Steam Flow to
Preconditioner kg/hr 11 11 Water Flow to Preconditioner kg/hr 19 18
Preconditioner Discharge Temperature .degree. C. 88 89 Moisture
Entering Extruder % wb 29.9 23.67 EXTRUSION INFORMATION Extruder
Shaft Speed rpm 499 499 Extruder Motor Load % 17 19 Water Flow to
Extruder kg/hr -- -- Extruder Additive Rate kg/hr 18 17.7
Control/Temperature 1st Head .degree. C. 50/50 50/53
Control/Temperature 2nd Head .degree. C. 80/90 80/78 Head/Pressure
kPa 2/0 2/2380 Knife Drive Speed rpm 539 1296 DRYER INFORMATION
Zone 1 Temperature .degree. C. 25 24 Zone 2 Temperature .degree. C.
25 24 Zone 3 Temperature .degree. C. 25 24 Retention Time - Pass 1
min. 2 0.9 Retention Time - Pass 2 min. 2 1.3 Fan Speed 1 rpm --
1406 Fan Speed 2 rpm -- 1406 Fan Speed 3 rpm -- 1406 FINAL PRODUCT
INFORMATION Extruder Discharge Moisture % wb 32 21.65 Extruder
Discharge Density kg/m.sup.3 705 695 Extruder Performance Stable
Stable Duration of Run min. 30 15 Run Rating Good Good
[0084] In Run #27 the extrudate was translucent with no uncooked
starch spots in it. In Run #28 the extrudate was clear in color and
very translucent.
[0085] While the preferred embodiments of the present invention for
forming cold water soluble starch products make use of a
dehydrating assembly as illustrated and described, the invention is
not so limited. For example, use can be made of a wide variety of
drying units, particularly those such as fluidized bed dryers which
involve conveying or suspending of the extrudate in a heated,
flowing airstream.
* * * * *