U.S. patent application number 11/407386 was filed with the patent office on 2007-04-05 for methods and apparatus for processing expandable food materials.
This patent application is currently assigned to Advanced Precision Engineering. Invention is credited to Richard DeSalvo, Kevin Hoyt, Alan Soucy.
Application Number | 20070075154 11/407386 |
Document ID | / |
Family ID | 37900952 |
Filed Date | 2007-04-05 |
United States Patent
Application |
20070075154 |
Kind Code |
A1 |
Hoyt; Kevin ; et
al. |
April 5, 2007 |
Methods and apparatus for processing expandable food materials
Abstract
The present invention relates in general to methods and
apparatus for processing expandable food materials, and more
particularly to methods and apparatus for low shear
thermo-mechanical processing of food materials. The invention can
include cooker and extruder apparatus for the customized production
of food products, including a compression module, a dryer module,
and a control unit.
Inventors: |
Hoyt; Kevin; (Sandown,
NH) ; DeSalvo; Richard; (Danvers, MA) ; Soucy;
Alan; (Georgetown, MA) |
Correspondence
Address: |
GOODWIN PROCTER LLP;PATENT ADMINISTRATOR
EXCHANGE PLACE
BOSTON
MA
02109-2881
US
|
Assignee: |
Advanced Precision
Engineering
Ipswich
MA
01938
|
Family ID: |
37900952 |
Appl. No.: |
11/407386 |
Filed: |
April 19, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60672902 |
Apr 19, 2005 |
|
|
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Current U.S.
Class: |
237/77 |
Current CPC
Class: |
A21C 11/16 20130101 |
Class at
Publication: |
237/077 |
International
Class: |
F24H 3/00 20060101
F24H003/00 |
Claims
1. A cooker and extruder apparatus for the customized production of
food products, comprising; a compression module; a dryer module;
and a control unit.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of U.S.
provisional patent application Ser. No. 60/672,902, filed Apr. 19,
2005, the entire disclosure of which is hereby incorporated herein
by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to methods and
apparatus for processing expandable food materials, in particular
methods and apparatus for low shear thermo-mechanical processing of
food materials. Additionally, the invention relates to a
self-actuating die and poppet valve combination for use with the
aforementioned methods and apparatus.
BACKGROUND OF THE INVENTION
[0003] Mass-produced breakfast cereals, some of which use
expandable food materials, have several disadvantages, for example,
high cost, the inclusion of preservatives and other unwanted
ingredients, and a lack of choice of ingredients. A consumer with
allergies, for example, is limited to certain selections and types
of products. Similar disadvantages exist for other mass-produced
food products, such as, for example, snack foods, croutons, bread
crumbs, and other types of puffed foods.
[0004] Various examples of methods and apparatus for processing
food materials can be found in U.S. Pat. No. 2,858,218, U.S. Pat.
No. 2,858,219, U.S. Pat. No. 4,187,727, U.S. Pat. No. 4,465,452,
U.S. Pat. No. 4,317,842, U.S. Pat. No. 4,503,127, U.S. Pat. No.
4,517,204, U.S. Pat. No. 4,537,786, U.S. Pat. No. 4,547,376, U.S.
Pat. No. 4,608,264, U.S. Pat. No. 4,615,894, U.S. Pat. No.
4,756,916, U.S. Pat. No. 4,820,470, U.S. Pat. No. 6,511,309, U.S.
Pat. No. 5,198,239, U.S. Pat. No. 4,569,848, U.S. Pat. No.
4,276,800, U.S. Pat. No. 4,405,298, U.S. Pat. No. 4,801,258, U.S.
Pat. No. 4,859,165, U.S. Pat. No. 5,773,043, U.S. Pat. No.
4,555,407, U.S. Pat. No. 5,577,410, U.S. Pat. No. 4,778,365, U.S.
Pat. No. 4,460,611, U.S. Pat. No. 4,548,571, U.S. Pat. No.
4,528,900, U.S. Pat. No. 4,578,027, U.S. Pat. No. 4,648,821, U.S.
Pat. No. 4,656,039, U.S. Pat. No. 4,698,000, U.S. Pat. No.
4,715,803, U.S. Pat. No. 4,743,458, U.S. Pat. No. 4,882,185, U.S.
Pat. No. 4,882,172, U.S. Pat. No. 4,469,475, U.S. Pat. No.
4,372,734, U.S. Pat. No. 5,403,603, U.S. Pat. No. 4,251,201, U.S.
Pat. No. 5,333,538, U.S. Pat. No. 4,406,603, U.S. Pat. No.
5,993,188, U.S. Pat. No. 4,268,532, U.S. Pat. No. 4,900,572, U.S.
Pat. No. 4,966,542, U.S. Pat. No. 4,456,446, U.S. Pat. No.
4,659,580, U.S. Pat. No. 5,198,257, U.S. Pat. No. 5,449,281, U.S.
Pat. No. 4,886,441, U.S. Pat. No. 4,999,206, U.S. Pat. No.
4,685,877, U.S. Pat. No. 6,764,701, U.S. Pat. No. 5,464,642, U.S.
Pat. No. 5,304,055, and U.S. Pat. No. 6,120,360, the disclosures of
which are hereby incorporated by reference in their entirety.
[0005] Apparatus for processing expandable food materials typically
utilize screw-type extruders that can impart excess shear on the
food material, thereby degrading the food material and the finished
product. Some of the methods and apparatus used for processing food
materials can negatively impact the taste and texture of the
finished product. For example, shear can degrade starch molecules
forming dextrin, an undesirable by-product, and degrading product
quality. Additionally, shear is also responsible for substantial
wear of screws and barrels, thereby shortening the life of the
equipment.
SUMMARY OF THE INVENTION
[0006] The invention generally relates to a low shear food
cooker/extruder for the customized production of breakfast foods
(such as cereals) and similar food products. In one embodiment, the
invention relates to a counter-top breakfast cereal apparatus
targeted for the consumer (home use) market. The cooker/extruder
can be used to freshly produce ready to eat (RTE) breakfast cereal
for the consumer. The cereal would be made on demand and, if
preferred, preservative-free, with ingredients tailored to
particular taste and texture preferences. Some of the advantages of
a apparatus and related processes in accordance with the invention
are that batches are made fresh and on demand; preservatives are
not required in the recipes; cost per batch is economical, whereas,
overhead costs passed on by commercial cereal manufacturers are
eliminated; consumers with allergies to specific food materials
control ingredient content of their recipes; and better overall
output quality due to minimized starch damage within the final food
product.
[0007] In one aspect, the invention relates to a very low shear
cooker/extruder utilizing a piston to extrude the expandable food
material. In one embodiment, the piston can include a rotating
mechanism to introduce a minimum amount of shear as may be
necessary to aid the cooking of the food product, but not enough to
damage the food product. Additionally, the cooking can be performed
under pressure as high as about 500 psi. A variety of dies or
nozzles can be used with the extruder to produce different finished
products and to accommodate different viscosity food products.
[0008] Generally, the cooker/extruder apparatus includes three
basic modules: a compression module, a dryer module, and a control
unit. The apparatus is capable of cooking, forming and puffing a
food product, such as, for example, cereals, snack foods,
breadsticks, croutons, pet foods, and textured vegetable proteins,
without the use of oil, hot air or gun-puffing, for example, to
puff the product. Additionally the apparatus could be used to
produce non-puffed foods, such as pellets or other half-product
made for later processing by other means, e.g., frying.
Furthermore, the apparatus could also be used as an analytical test
machine to measure properties, for example viscosity, of materials.
The apparatus can vary in size and configuration to suit specific
applications. For example, a relatively small manually operated
unit could be produced as a home appliance. A larger version could
be manufactured for in-store production, such as might be found in
supermarket bakeries or health-food stores. A larger and more
sophisticated automated machine may also be produced.
[0009] In one embodiment, the compression module includes a chamber
for inserting and processing raw food materials, a quick-release
sealed chamber cover for maintaining high pressure during the
cooking/extrusion process, a heating element that surrounds the
chamber, a variable speed piston for ejecting processed food
materials from the chamber, a piston drive mechanism, and an
adjustable pressure-activated nozzle for controlling the expansion
rate of food materials ejected from the chamber. The piston drive
mechanism could be mechanically (e.g., a screw), electrically,
hydraulically, or pneumatically driven.
[0010] The dryer module, in one embodiment, includes a variable
speed blade for cutting extruded/expanded food material to desired
lengths, a bin for capturing and containing said food material, a
heater for drying and toasting said food material, a blower for
circulating said food material during the drying/toasting process,
and an enclosure that houses the blade, bin, heater and blower. In
one embodiment, the control unit includes electro/mechanical
hardware and circuitry, which controls all electrical, mechanical,
and physical aspects of the cooking, extrusion, drying and toasting
processes. All of the necessary hardware and circuitry is housed
inside a grounded enclosure.
[0011] In another aspect, the invention relates to methods of
producing food products with low or very low shear. The methods
involve thermo-mechanically processing the food products. The
methods include introducing a raw or partially processed food
product into a compression module, heating and/or pressurizing the
food product to cook the product, and extruding the product under
minimal shear.
[0012] In another aspect, the invention relates to a food product
as produced by a method in accordance with one embodiment of the
invention, such as, for example, cereal or a puffed cheese snack.
The methods and apparatus of the invention can be carried out with
a variety of raw ingredients to suit a particular user's tastes.
For example, prestressed or pregelatinized ingredients could be
used, such as melted starches. The apparatus can include additional
modules for modifying the extruded food product, for example for
flavoring or combining with other food products.
[0013] In another aspect, the invention relates to a self-actuating
poppet valve. The poppet valve is used in the compression module to
trigger the extrusion process. In one embodiment, the valve is a
pressure-actuated poppet valve that connects the chamber to the die
or nozzle when a pre-determined pressure is reached within the
chamber.
[0014] These and other objects, along with advantages and features
of the present invention herein disclosed, will become apparent
through reference to the following description, the accompanying
drawings, and the claims. Furthermore, it is to be understood that
the features of the various embodiments described herein are not
mutually exclusive and can exist in various combinations and
permutations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In the drawings, like reference characters generally refer
to the same parts throughout the different views. Also, the
drawings are not necessarily to scale, emphasis instead generally
being placed upon illustrating the principles of the invention. In
the following description, various embodiments of the present
invention are described with reference to the following drawings,
in which:
[0016] FIG. 1 is a schematic side view of a compression module for
an apparatus for processing expandable food materials, in
accordance with one embodiment of the invention;
[0017] FIG. 2A is a schematic perspective view of the compression
module of FIG. 1;
[0018] FIG. 2B is a second schematic perspective view of the
compression module of FIG. 1;
[0019] FIG. 2C is a third schematic perspective view of the
compression module of FIG. 1;
[0020] FIG. 2D is a fourth schematic perspective view of the
compression module of FIG. 1;
[0021] FIG. 3 is an exploded schematic perspective view of the
compression module of FIG. 1;
[0022] FIG. 4 is a table of parts for the compression module of
FIGS. 1-3;
[0023] FIG. 5A is a schematic perspective view of a dryer module
for an apparatus for processing expandable food materials, in
accordance with one embodiment of the invention;
[0024] FIG. 5B is a second schematic perspective view of the dryer
module of FIG. 5A;
[0025] FIG. 6A-6I are schematic perspective views of the dryer
module of FIG. 5A, in various stages of construction;
[0026] FIG. 7 is a table of parts for the compression module of
FIGS. 5A-6I;
[0027] FIG. 8 is a schematic view of a control unit for an
apparatus for processing expandable food materials, in accordance
with one embodiment of the invention;
[0028] FIG. 9 is a schematic view of three positions descriptions
for the toggle switch of FIG. 8;
[0029] FIGS. 10A-10F are schematic views of a housing and valve for
a self-actuating die and poppet valve combination, in accordance
with one embodiment of the invention;
[0030] FIG. 11 is a schematic view of a piston and valve for a
self-actuating die and poppet valve combination, in accordance with
one embodiment of the invention; and
[0031] FIG. 12 is a schematic view of a spacer and spring for a
self-actuating die and poppet valve combination, in accordance with
one embodiment of the invention.
DETAILED DESCRIPTION
[0032] Embodiments of the present invention are described below. It
is, however, expressly noted that the present invention is not
limited to these embodiments, but rather the intention is that all
equivalents and all modifications that are apparent to a person
skilled in the art are also included. In particular, the present
invention is not intended to be limited to any specific food
material or end product.
[0033] The compression module includes the components listed and
arranged as shown in FIGS. 1-4. FIGS. 8 and 9 show an electrical
schematic representing one embodiment of a control unit for
operating the apparatus. The dryer module includes the components
listed and arranged as shown in FIGS. 5A-7. The operation of the
various modules and components are described hereinbelow.
[0034] The invention also relates to a variety of methods of
producing food products. Generally, the operation of the apparatus
includes the following steps. Food materials of a particular recipe
are inserted into the chamber of the compression module and the
chamber cover is attached and sealed to the chamber and locked. The
heating element is activated to begin the cooking process. As the
closed-volume cooking process proceeds, the pressure and boiling
point of the food materials continuously elevate above their
atmospheric levels, and the starches within the food material
transform to a plasticized state. After a specified elapsed cooking
time (dependant on recipe and ingredient quantities, for example),
the heating element is deactivated to terminate the cooking
process. The piston is then activated to begin the extrusion
process by decreasing the volume of the chamber and, thereby,
further increasing the differential pressure between the food
materials within the chamber and atmospheric pressure outside of
the chamber.
[0035] Once the pressure of the food materials within the chamber
reaches a pre-determined level, the nozzle or valve opens, allowing
the pressurized food material to flow from the chamber. The piston
remains in motion until all food materials within the chamber have
been ejected. Approximately ninety five percent of the water
content within the food material instantaneously boils upon exit
from the nozzle, causing the ejected food material to expand.
Expansion rate is dependant upon original water content of the
recipe and is controlled by multiple mechanical parameters, such as
nozzle orifice size and piston speed. At ejection, the plasticized
starches throughout the food material go through a glass
transition, that is, they form cellular structures that cool
rapidly to maintain the size, shape and texture of the expanded
food product.
[0036] The expanded food product flowing from the compression
module nozzle optionally enters the dryer module through an opening
in the enclosure wall thereof. After exiting from this opening, the
food product is cut into equal length sections by a spinning blade.
Section length is selected based on the desired size and/or shape
of the finished food product. Section length is determined by the
speed of the blade. Depending on the type of food product produced,
the dryer module may not be needed as the product can be air dried
and manually cut or otherwise manipulated. Additionally, other
processes can be carried out to sweeten, flavor, color, texturize,
enrich, and otherwise treat the finished food product.
[0037] After being cut, the food sections are gravity fed into a
perforated holding bin. Once the complete batch of food product has
been sectioned and is in the holding bin, a heater and a blower
unit are both activated. In one embodiment, the heater is located
directly beneath the holding bin and has an output of approximately
400 watts and is toggled on and off by a thermostat control. The
heater's function is to toast the food product for added flavor and
decrease its moisture content to, for example, between about three
percent and about five percent. The desired resultant moisture
content will depend on the food product being produced. In one
embodiment, the blower unit is located directly beneath the heater,
has an output of approximately 20 cfm, and remains on throughout
the drying/toasting process. The blower's function is to promote
even heating and to prevent burning of the food product by
circulating the food sections within the bin during the
drying/toasting process.
[0038] The size of the apparatus and the size and arrangement of
the various components of the apparatus will be selected to suit a
particular application. In one embodiment, a cylinder having a
diameter from about 0.25'' to about 4'' is used. The cylinder
stroke can be from about 0.5'' to about 18''. The apparatus can be
scaled up or down to suit the particular application, for example
as a home appliance or for an industrial application. For example,
in the compression module, the cylinder size and quantity will be
selected based on the amount of product to be produced, the heat
transfer requirements, and the desired cycle time. For example,
better heat transfer permits the use of raw feeds and higher
temperatures that will allow operation at reduced moistures for
better product quality.
[0039] One of the considerations when selecting the size of the
cylinder is the time required to achieve a desired level of heat
penetration, which is approximately proportional to the square of
the cylinder's diameter. For example, if it takes one hour to heat
a 2'' cylinder, we expect the same results in 15 minutes with a 1''
diameter cylinder. And, using the same piston stroke, the
production rate will remain constant. Each shot will have 1/4 of
the original quantity, but will happen four times more frequently.
Moreover, multiple cylinders (like in a reciprocating engine) can
be used to increase the product output. A description of thermal
penetration can be found in Heldman and Singh, Food Process
Engineering, pp. 124-130, the disclosure of which is hereby
incorporated by reference in its entirety.
[0040] In another embodiment, an annular piston can be used.
Although a more complex design, converting from a circular
cross-section to an annular cross-section vastly increases the heat
transfer area (heating inside and outside the annulus) with a
dramatic decrease in cycle time and improvement in product
uniformity. For example, replacing the solid 2'' cylinder with a
hollow 3'' cylinder would require an inner diameter of 2.24'' for
the same volume with the same stroke. But the heat transfer area
would increase by a factor of about 2.6, and the relative distance
that the heat would have to penetrate would be only about 38% of
that in the 2'' cylinder. A one-hour heating cycle could be reduced
to about 8.8 minutes with this design. With that reduced cycle
time, the production rate would increase about 6 times.
[0041] In one embodiment, the cylinder head is insulated to, for
example, minimize condensation at the cold spot in the center of
the product and the loss of heat to the atmosphere. Additionally,
the cylinder wall thickness can be varied to alter the heat
transfer properties. The material of the cylinder can be, for
example, stainless steel, an aluminum/stainless sandwich (as used
in waterless cookware), or normal mild steel with a stainless
liner.
[0042] The apparatus of the present invention is an improvement
over the prior art at least because of its lack of shear until the
product enters the final die orifice, which is an inherently
high-shear operation required to create the desired product
characteristics. Shear earlier in the process (for example in the
screw of a standard extruder where it is responsible for generating
most of the heat required to cook and puff the product) does little
to build texture, and can be detrimental to product quality by
damaging, or dextrinizing, the starch molecules. The present
invention utilizes external methods of heating, such as conduction
heating, thereby eliminating the damaging shear.
[0043] The size of the die should be selected to optimize discharge
speed, but will also vary depending on the raw materials used and
the food product to be produced. There is an optimum extrusion flow
rate for any particular die size. For larger product size,
requiring a larger die hole, the piston speed can be increased. The
die orifice itself can be streamlined for better product
formation.
[0044] Moisture is another operating parameter that affects the
final food product produced. In one example, the mix used in the
test was formulated to be at 25%, which is higher than normally
used for expanded products. After mixing for about 1 hour, the
moisture was measured by loss-of-weight in a microwave oven to be
about 17%, which is about ideal for standard corn-based snack
extrusion.
[0045] The following test data is included to be illustrative
only.
[0046] I. Power Input and Shell Temperature:
[0047] In one test, the power to the electrical heater was adjusted
to maintain an average shell temperature of about 453 deg. F.,
starting with an initial power setting of about 100% and dropping
as the sample heated up to avoid overheating the outer surface of
the product within the cylinder. Applying an exponential model, a
final power setting of about 51% is expected at equilibrium.
Assuming that the potentiometer setting is proportional to the
actual power delivered, about half of the total coil power at that
temperature is lost to the atmosphere.
[0048] II. Heat Penetration--Pressure and Product Temperature:
[0049] Moisture migrates from the outer portions of the cylinder to
the center due to the temperature gradient. The center portion
remains cool for a period of time required for the heat to diffuse
inward, and then its temperature starts to rise, eventually coming
to equilibrium with the outer portion. This picture is complicated
somewhat by the head space above the product which allows the
moisture to move quickly to those cooler portions, and the effect
of the unheated cylinder head which prevents that top-center
portion from coming to equilibrium. Some of the energy loss noted
above would be through the head. [0050] Center Temperature
Estimation: It was assumed that the temperature at the top center
was that which would be in equilibrium with the pressure measured
in the head space (steam, created by the hot outer portion, would
condense in the center at a temperature in equilibrium with the
pressure). [0051] Equilibrium Temperature: Using the exponential
model, an equilibrium final temperature for the top center position
was estimated at about 249 deg. F., considerably lower than the
shell temperature, and much lower than the normal temperature range
usually required for good expansion. An additional point on this
curve was generated by extrapolating the pressure curve backward in
time to zero pressure (one atmosphere absolute) where the
temperature would be about 212 deg. F. This occurred at about 43
minutes.
[0052] Dimensionless Format: Unsteady-state heat transfer data are
usually converted into dimensionless form for analysis. Knowing the
initial and final temperature, the conversion is: UTC = T f - T T f
- T i ##EQU1##
[0053] where: [0054] T.sub.i=initial temperature [0055]
T.sub.f=final temperature [0056] UTC=unaccomplished temperature
change
[0057] UTC goes from 1 to zero at infinite time.
[0058] Penetration Time: The resulting curve fit the exponential
model well, and was extrapolated back to UTC=1 for an initial
temperature of about 70 deg. F. That occurred at about 25.6
minutes, which is about how long it took for the first heat to
penetrate to the center of the cylinder.
[0059] Having described certain embodiments of the invention, it
will be apparent to those of ordinary skill in the art that other
embodiments incorporating the concepts disclosed herein can be used
without departing from the spirit and the scope of the invention.
Accordingly, the described embodiments are to be considered in all
respects only as illustrative and not restrictive.
* * * * *