Note: Descriptions are shown in the official language in which they were submitted.
CA 02346964 2001-05-11
PUFFED FOOD STARCH PRODUCT
This application is a division of copending commonly assigned Canadian Patent
Application No. 2,267,088 filed March 29, 1999.
Technical Field
This invention relates generally to improved puffed-food starch products made
from cereal
grains or other food starches, into various shapes, and the methods for their
manufacture. More
particularly, the present invention relates to puffed-rice snacks with
improved crispiness, and
appealing visual and physical texture, and processes of preparing such snacks.
Background of the Invention
Snacks have long been a household staple around the world and range from
treats to dietary
supplements. However, not too long ago a nutrition trend found chocolates,
candies, ice cream, and
other naturally and artificially sweetened confections, as well as potato
chips, pretzels, corn chips, and
the like, being replaced by more healthy products. The terms "low fat", "no-
fat", and "light" have
become the watch words of the health conscious in the '90's. The trend has
seen the popularity of
puffed, or sometimes referred to as popped grain snacks, especially those made
of corn and rice,
steadily climb.
Very successful products have been made in the form of cakes generally made of
puffed corn
or rice. While these products had a here-to-fore acceptable amount of
crispiness, they suffered from
an unpleasant texture, usually nearest the core of the cake, resulting in the
product sticking in teeth.
The products are hockey puck-shaped (uniform in all three dimensions) and lack
the appealing visual
texture of conventional snack foods. The size of these snack cakes is also
relatively large in size
(approximately a three to four-inch disk-shaped cake). This size, as a single
portion, can lead to a
substantial amount of waste for some consumers, especially children. To
address the problem of
waste, a "mini-cake," or smaller version of the original cake (about a one to
two-inch disk-shaped
cake or cracker) was introduced. The problems of texture and appearance,
however, remained.
CA 02346964 2001-05-11
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Examples of methods for making conventional grain cake products are disclosed
in the
described methods of U.S. Patent No. 4,888,180 to Wu. These cake-forming
devices are most
frequently used with rice as the cereal grain since rice is capable of
relatively easy expansion into a
self supporting cake. Statistics show that the availability and versatility of
rice have not only made
it an industry favorite, but a consumer favorite as well. The annual world
rice harvest in the early
1990's exceeded 510 million metric tons, an increase of about 30 percent over
the average during the
period from 1979 to 1981. Rice grains are extensively used as human food,
constituting the principal
food of almost one-half the human race. The leading rice producers are China,
with 36 percent of
world output in the early 1990's, and India, with 22 percent. In the United
States, production
averaged close to 7 million metric tons; Arkansas, California, Louisiana, and
Texas were the leading
rice-producing states.
Rice puffing and, in general, cereal puffing (or cereal popping) methods are
well established
in the prior art. Generally, methods known in the art rely primarily on a
moisture content in the
grains for puffing. The moisture content can be varied by many processes, such
as: drying; cooking;
parboiling; and, tempering. Examples of attempted improvements in processing
methods are
described in US. Patent Nos. 4,281,593 to Gevaert, 4,328,741 to Yoshikazu, and
4,667,588 to
Hayashi.
There are two generally practiced methods for expanding or puffing grains: ( 1
) heating the
kernels of grain until they become extensible (i.e. until the starch becomes
amorphous or flowable)
at which point further heating permits evaporation of moisture (and out-
gassing of some minor
amounts of other gases entrained in the grain) which causes expansion (bubble
formation) in the
amorphous starch; (2) heating the grain kernels to a flowable state at
atmospheric pressure, then
suddenly reducing the pressure (partial vacuum) again permitting enhanced
vaporization and out-
gassing, and again causing expansion (bubble formation) in the amorphous
starch; and, (3) heating
the grain kernels to a flowable state in a chamber where pressure is permitted
(or caused) to build,
then suddenly reducing the pressure to atmospheric permitting enhanced
vaporization and out-gassing
and again causing expansion (bubble formation) in the amorphous starch.
This latter method, is most conventionally used to make rice cakes of both the
larger and
"mini" sizes. This latter method is carried out in what is commonly referred
to as rice popping
CA 02346964 2001-05-11
3
machines. These machines provide a chamber defined by heated chamber walls.
Once the pre-puffed
grain is placed in the chamber, it is closed to a pressure seal. The food
starch is heated by contact
with the chamber walls. The amount of food starch, i.e. the amount of grain
kernels loaded into the
chamber, relative to the volume of the chamber, and amount of expansion, cause
the puffed product
S to generally conform in all three dimensions to the shape of the chamber.
One problem with conventional rice popping processes is that the filling of
the entire volume
of the popping chamber upon expansion, may limit the bubble size formed, or
full expansion of the
bulk amount of the food starch, or both. This may account for a less than
filly crisped product and
a teeth-sticking texture ofthe resulting rice cake. It is certainly
responsible for the hockey puck-shape
of the product, which heretofore was thought to be desirable.
Another problem which exists in use of rice popping equipment is trying to
balance providing
sufficient time to present good conditions for full expansion of the food
starch, while at the same time
trying to minimize chamber residence time to achieve high production rates. To
date, this balance,
has produced the conventional rice cakes discussed above.
It is well known that, the degree and ease of puffing is affected by many
factors such as: the
type of grain, the type of preprocessing (e.g. milling), the condition of the
grain (e.g. moisture
content), and the type of starch contained in the grain. Another advancement
in puffing food starch
is to pufffood starch which has been floured, and to extrude it into a
discrete size and shape. Such
extruded pieces are cooled and dried to a state of desired moisture content
and hardness for
acceptable handling and storage. To date, such puffing has been limited to
oven puffing or deep
frying. The resulting products, however, are relatively uniform throughout the
snack piece, and
provide a monolithic texture to the mouth when eating them. The same can be
said for the products
made from the more conventional process of extrusion puffing.
The inventor is unaware of a cake-type product ever being attempted using such
pelletized
stock. Further, it appears that prior to the present invention, it has never
been contemplated to
employ such a pelletized pre-product in a rice popping machine or related
process.
In sum, despite the improvements being made in the field of making puffed
snack cakes from
food starches, in particular rice grain, insufficient attention has been given
to improving the overall
visual and physical texture (e.g. crispiness) and appearance of the product.
The present invention
CA 02346964 2002-10-03
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addresses these issues as well as solving the problems discussed above and
providing other
advantages which will become apparent to those skilled in the art upon reading
the accompanying
specification and claims.
Summary Of The Invention
The present invention provides puffed-food starch snacks having an improved
crispy
texture and a more aesthetic appearance and methods for preparing them.
In general terms, the products are snack chips, cakes, crackers or the like,
made from food
starch. Preferably, the starch material is provided primarily in the form of
individual kernels or
pellets of a cereal grain, such as rice, corn, wheat, rye, oats, millet,
sorghum, barley, buckwheat,
or mixtures thereof. Quantities of other food starches may also be employed as
a co-mixed
constituent, or as the primary source of bulk starch material, for example
potato starch. A
quantity of the food starch is puffed (expanded) in a manner which forms a
snack product of
considerable crispiness, lightness, and unique texture to both the mouth and
eye.
According to one aspect of the invention according to the present application,
a puffed
snack product comprises a puffed starch body having a generally regular
perimetrical shape, and
opposed upper and lower surfaces. At least one of the upper and lower surfaces
has a
substantially wavy contour such that it appears as though individual kernels
of grain are joined
to one another. It is preferred that the substantially wavy surface of the
starch body comprises
hills and valleys, noted by the rise and fall of the surface along a parallel
plane.
The invention in accordance with the present invention may, however, be
defined
generally as a puffed snack product comprising: a puffed starch material body
having a generally
regular perimetrical shape with opposed upper and lower surfaces; and at least
one of the upper
and lower surfaces having a substantially wavy contour appearing as though
individual kernels
of grain were joined to one another; the puffed snack product being made by
the method
comprising the steps of: providing a puffing chamber which permits
unconstrained total volume
expansion of a food starch material to produce the puffed snack product;
placing a bulk amount
of the food starch material into the puffing chamber; and causing a volumetric
expansion of the
bulk amount of food starch material placed in the chamber to form a single,
unitary puffed food
starch material product by constraining
CA 02346964 2001-05-11
expansion of the bulk amount of food starch material in at least a first
dimension, while permitting
unconstrained volumetric expansion of the bulk amount of food starch material
in at least a second
dimension.
In a preferred embodiment, the puffed snack product is comprised primarily of
rice starch, but
may further include puffed corn starch, puffed wheat starch, puffed potato
starch, or the like.
In other presently preferred embodiments, the puffed snack product may be
comprised
primarily or predominately of puffed corn starch, puffed wheat starch, or
puffed potato starch, with
combinations of other such grains possible. Presently, a preferred
perimetrical shape of the food
product is generally circular, hence a rounded cake in two dimensions.
Alternatively, other
embodiments may include a perimetrical shape which is generally triangular,
square, rectangular, or
any other such geometric or fanciful shape as may be thought at the time to
have consumer appeal or
processing, handling, or packaging advantages.
According to another aspect ofthe invention, the bulk cake product is
comprised of an amount
of food starch in the form of a plurality of individual whole kernels of
grain, puffed together. At least
a portion of these whole kernels may be rice kernels, wheat kernels, or both,
and may additionally
include corn grits.
According to yet another aspect ofthe invention, the cake or snack body is
formed from a bulk
amount of food starch comprised of a plurality of individual pellets (formed
from starchy flour) all
puffed together. Such pellets are preferably made from rice flour, wheat
flour, corn flour, potato flour
or the like, and may additionally include corn grits. A sufficient amount of
pellets (and corn grits, if
desired) capable of becoming amorphous in the puffing chamber should be
provided, such that all of
the pellets, and grits, touch at least one other pellet, or grit, after
becoming amorphous.
The step of constraining expansion may additionally include constraining
expansion ofthe bulk
amount in a third dimension as well. The constraining may achieve a defining
of the general shape
of the final product in the first dimension, or in both the first and third
dimensions. The defined shape
may be provided by, in one particular embodiment, constraining expansion with
certain of the inner
surfaces of the puffing chamber. Preferably, for the snack cake disclosed in
the example below, the
unconstrained second dimension is height.
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Another aspect of the method of the present invention includes predetermining
the bulk
amount of food starch material to be placed into the chamber. The
predetermining should provide
a sufficient amount of whole kernels (or corn grits, if desired) capable of
becoming amorphous, such
that all of the kernels, and grits, touch at least one other kernel, or grit,
after becoming amorphous.
Where pellets are used, the method may further include forming the pellets
generally to the
size of a whole kernel of grain selected from the group of grains including
rice, wheat, barley, oats,
rye, and corn.
Another aspect of the invention provides for puffing a food starch capable of
becoming
amorphous into a food starch product, wherein the food starch is first floured
then pre-gelatinized
in an extruder under a pressure and temperature. The food starch is then
extruded and cut into pellets.
The pelletized food starch is placed into a puffing chamber where increasing
the pressure and the
temperature in the chamber causes the pelletized food starch to become
amorphous. By quickly
reducing the pressure in the chamber, the amorphous starch pellets expand.
The pellets are believed to provide superior puffing, (at least relative to a
given time,
temperature cycle in mass production) to whole kernels. While presently
unproven, the advantages
are believed to be that: ( 1 ) the pellets are pre-gelatinized and may allow
more of the heat energy (in
the given cycle time or amount of thermal energy) to contribute to water
vaporization and bubble
formation, (as opposed to providing energy to accomplish a greater crystalline
phase change) than in
a grain kernel); (2) the pelletized rice has been pre-floured, hence the
mechanical, and physical
boundaries of the cellular structure have already been broken down leading to
a more uniform
expansion with less (heat) energy required to break down the cellular
structure; and, (3) the uniform
pellet structure has a more uniform distribution of both starch and moisture
for improved crisp,
puffing.
According to another aspect of the invention, the extruded food starch pellets
may be cooled
under sufficiently controlled (slowly) parameters to reduce stress in the
pellet (i. e. an annealing of the
pellets). This should reduce the energy required for possible annealing in the
popping chamber. Also,
the slow drying should enhance endurance of further handling without
fracturing. The extruded
pellets should be provided with sufficient drying to enhance shelf life and to
prevent pellets from
sticking together in storage.
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It is also possible, that once gelatinized, the pellets are cooled in such a
way as to reduce
recrystallization of the starch. This may also assist in puffing in that for a
fixed amount of energy
input, energy is not wasted unduly on annealing in the puffing chamber.
However, such a cooling may
be at odds with the slow cooling for stress reduction. While one type of
cooling may be used as a
trade off for the other, stress reduction presently looks to be the preferred
goal.
Brief Descriation of the Drawings
In the drawings,
FIGURE 1 is cut-away side view depicting a puffng machine used in the present
invention in
a completely open position;
FIGURE 2 is a similar view of the puffng machine of FIGURE 1 showing the
placement of
food starch within a couple of chambers;
FIGURE 3 is a similar view of the puffing machine of FIGURE 1 showing the
sealed
chambers;
FIGURE 4 is a similar view of the puffing machine of FIGURE 1 showing just
subsequent to
breaking the seal on the chambers;
FIGURE 5 is a similar view of the puffing machine ofFIGURE 1 showing the upper
mold fully
retracted;
FIGURE 6 is a similar view of the puffing machine of FIGURE 1 showing the
final product
being ejected from the mold;
FIGURE 7 is a top view of a supply plate for the present invention;
FIGURE 8 is a perspective view of a puffed starch product made in accordance
with one
embodiment of the present invention;
FIGURE 9 is a top view of a puffed starch product as shown in FIGURE 8;
FIGURE 10 is a bottom view of a puffed starch product as shown in FIGURE 8;
FIGURE 11 is a first side view of a puffed starch product as shown in FIGURE
8;
FIGURE 12 is second side view of a puffed starch product as shown in FIGURE 8;
FIGURE 13 is a third side view of a puffed starch product as shown in FIGURE
8;
FIGURE 14 is a fourth side view of a puffed starch product as shown in FIGURE
8;
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FIGURE I 5 is a perspective view of another puffed starch product made in
accordance with
one embodiment of the present invention;
FIGURE 16 is a perspective view of another puffed starch product made in
accordance with
one embodiment of the present invention;
FIGURE 17 is a perspective view of another puffed starch product made in
accordance with
one embodiment of the present invention;
FIGURE 18 is a flow chart illustrating an embodiment of the present method for
producing
a puffed food starch product;
FIGURE 19 is a flow chart illustrating another embodiment of the present
method for
producing a puffed food starch product using pelletized food starch;
FIGURE 20 is a flow chart generally illustrating the operation of the puffing
machine.
Detailed Description of the Preferred Embodiment
While the invention is susceptible of embodiment in many different forms, this
disclosure will
1 S described in detail preferred embodiments of the invention with the
understanding that the present
disclosure is to be considered as an exemplification of the principles of the
invention and is not
intended to limit the broad aspect of the invention to the embodiments
illustrated.
Product
The puffed or popped food starch food products of present invention provide a
number of
advantages over prior puffed food starch cake or cracker products. It is
believed that the products
are lighter, crispier, and have a more appealing visual texture as well as
texture to the mouth when
consumed. In some cases products made in accordance with the invention are
believed to have a more
natural unprocessed appearance, as illustrated in FIGURES 8-17.
However, the wavy, natural appearance provides fi~nctional advantages over the
prior art as
well. The undulating surface allows snack dips to be more easily scooped, much
like a potato chip
or corn chip than hockey puck-shaped cakes. Additionally, the present product
may be sprinkled with
flavoring during manufacturing, including such savory flavors as barbeque,
sour cream, cheese, garlic
& onion, and most any other popular snack flavor. The highly textured surface
provides longer
CA 02346964 2001-05-11
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retention of granular or crystalline flavor coatings. Additionally, because
the top and bottom surface
areas of each chip are larger than a standard flat surface of prior art cakes,
a greater amount of
flavoring may be applied. More flavoring may improve the overall flavor of a
product that has
enjoyed past commercial success.
Products according to the invention may be in the form of a snack chip, cake,
or cracker.
They can be made from individual kernels according to certain aspects of the
invention and from
individual pellets of extruded food starch material according to other aspects
of the invention.
Disclosed herein are cakes made from a cereal grain, such as rice, corn,
wheat, rye, oats, millet,
sorghum, barley, buckwheat, or mixtures thereof. A quantity of the grain is
puffed (expanded) in a
manner which forms a snack product of considerable lightness and crispiness
over previous puffed-
grain snacks.
The puffing phenomenon results from the sudden expansion of water vapor
(steam) from
moisture held within the starch material of the granule (and some out-
gassing). The particle is fixed
in its expanded state by the dehydration resulting from the rapid diffusion of
the water vapor out of
it. The moisture level is considered an important factor in puffing grain.
Before puffing, the grain or
pellet preferably should be maintained at no less than 3% moisture in order to
achieve the desired
extent of puffing and crispness ofthe final product. The preferred embodiment
has a moisture content
which falls within the range of from about 8% to about I 8% (by weight)
moisture, with about 8% to
about 13% (by weight) being more preferred, and about 10% to about 12% being
the most preferred
moisture content. Moisture contents outside of the 8-18% range may cause a
decreased puffing on
the one hand, and collapse of an already puffed product on the other hand.
Rice grain is preferred for many reasons, including its capability to expand
with relative ease
into a self supporting cake product. FIGURES 8-14 show various views of one
embodiment of a
snack cake according to the present invention. The puffed snack product of the
present invention
comprises a puffed starch body 10 having a generally regular perimetrical
shape, and opposed upper
and lower surfaces 12, 14. The perimetrical shape of body 10 is circular.
Other shapes, are
contemplated, for example, other geometric shapes: triangular; square;
rectangular; etc., and fancifizl
shapes may provide particular advantages in some instances. FIGURES I S-17
show food starch
products with surface variations.
CA 02346964 2001-05-11
Referring to FIGURES 8-14, the upper surface 12 and the lower surface 14 have
a
substantially wavy contour, and each surface 12, 14 has a general appearance
which permits visual
discrimination between individual kernels of grain 16 as they are joined to
one another. It is preferred
that the substantially wavy surface of the starch body 10 comprises hills 17
and valleys 18, noted by
5 the non-uniform rise and fall of the surfaces I 2, 14.
While the preferred starch body 10 is comprised primarily ofrice, it may
further include corn,
wheat, potato, oats, rye, barley, buckwheat, potato, or any combination of
these or other suitable
sources of puffable food starch. Hereafter, the terms "good" or "goods" are
intended to describe
starch bearing materials, including cereal grains, seeds, tubers, and the
like, which are used in the
10 present process to make up the food starch of the starch bodies such as
body 10 or in making up the
bulk amount of food starch placed in the puffing chamber. Where applicable,
these goods may be
supplied in the form of ground flour, whole kernels, or in a pelletized form.
Mixtures of goods in the
form of flour, or mixed whole kernels or mixed pellets may also be used in
accordance with the
present invention, with varying results.
With respect to flour and whole kernels, single goods or mixtures of goods may
be used to
create a suitable puffable food starch composition. As rice is the preferred
food starch in the disclosed
embodiment of body 10, it should be understood it will be the preferred
predominate good used in
mixtures for many of the disclosed methods. A predominately rice flour mixture
may contain rice
flour within the range of about 51 % to 100% by weight. Similarly,
predominately corn flour mixture
would be predominately corn flour (i.e., at least 51% by weight). The
remaining percentage, up to
49% by weight, may be made up of any one or more of other floured goods. This
is equally true for
a mixture of predominately rice grain, or predominately corn grit (i. e.,
cracked corn). It should be
noted that moisture content of the respective starch constituents is counted
in its weight percentage.
Pellets are more variable than either flour or whole kernels. The pellets
themselves may be
made from a mixture of goods from a flour form, and the entire composition may
be comprised of
several different kinds of pellets. For instance, "A" pellets may be formed
from a mixture of 75% by
weight rice flour and 25% by weight corn flour, while "B" pellets may be
formed from 60% by weight
rice flour and 40% by weight potato flour. A first recipe may call for 50% by
weight of "A" pellets
CA 02346964 2001-05-11
11
and 50% by weight of 'B" pellets, while a second recipe may require 90% by
weight "A" pellets and
only 10% by weight of 'B" pellets. The various combinations are nearly
infinite.
Of the three forms of goods disclosed, pellets are a preferred form, according
to a separate
aspect of the invention. Pellets provide excellent textural features (e.g.,
crispiness, contour, etc.),
produce a high-quality puffed product, and allow more precise control of
moisture content.
While rice is the preferred good for the pelletized form in the present
invention, other embodiments
of the puffed snack product may be comprised primarily of corn, wheat, or a
puffed potato starch,
with combinations and other such grains (or starches from sources other than
grains) also possible.
Part of what gives the present invention its unique surface contour is the
composition of the
bulk food starch. The various goods will all have different expandability,
partly dependent upon
moisture content and partially due to the differing starch characteristics,
compositions, or pre
processing (such as pre-gelatinization). By assembling a bulk food starch
ofpredominately rice (either
flour, whole kernels, or pellets) interspersed with, for instance, the
preferred corn grits, the puffed
product will have natural surface and texture variations due to varied
expansion. Therefore, to
I5 facilitate this affect in the present invention, at least a portion of the
bulk food starch in certain
embodiments will be enhanced by the inclusion of corn grits which do not
expand as much as rice
pellets or kernels.
Referring again to FIGURES 8-14, regardless ofthe goods) or form used,
according to one
aspect of the invention, the product has a generally predefined perimetrical
shape. Preferably, the
perimetrical shape of the food product is one that is appealing to consumers
and is suitable for use in
a chamber-type popping machine. Applicant has found a circular shape to meet
both of these
requirements. It is also believed that there may be textural advantages of the
circular shape.
In order to form the preferred product, which is more easily understood with
reference to the
described methods, a sufficient amount of whole kernels or pellets (and corn
grits) capable of
becoming amorphous, should be provided such that all of the whole kernels or
pellets (and grits)
touch or contact at least one other whole kernel or pellet (or grit) after
becoming amorphous. In
other words, the bulk food starch is capable of melting into a single flowable
mass. This means that
the amount of bulk food starch used for making the present inventive product
is an important feature,
as discussed below.
CA 02346964 2001-05-11
12
The area of contact between two or more of the kernels or pellets form a
connective boundary
after they become flowable. This boundary defines the area of connection
between kernels or pellets.
The preferred puffed product is most readily broken apart at these boundaries,
as opposed to breaking
within the body of the puffed kernel or pellet. This adds to the aesthetic
appearance of the product
according to the present invention. Prior art grain cakes are typically
comprised of indistinct or less
distinguishable boundaries between puffed kernels, breaking along less
visually determinable lines.
Another textural distinguishing aspect ofthe present invention over the prior
art relates to the
product thickness. The preferred product is typically a single layer,
approximately one grain thick.
This helps insure contact between individual kernels, pellets, and grits
occurs on no more than two
dimensions (i.e., primarily side-to-side connection). This, in turn, insures
the added eating textural
appeal of individual kernels or pellets in each puffed product. Conversely,
the prior art cakes are
several grains thick, causing three dimensional contact (i.e., side-to-side
and top-to-bottom
connections). Such three-dimensional contact removes the added aesthetic and
textural crispiness and
appeal of the individual kernels or pellets within the cake. This again
relates to the amount of bulk
food starch relative to the puffing chamber volume and resting area.
Processes
In many prior art processes, an amount of food starch (in whole kernel form
only) is added
to a pufftng chamber so that upon expansion the food starch fills the entire
chamber. The result is a
puffed product conformed exactly to the size and shape of the chamber, in
substantially the form of
a disk. This is very different than the present invention.
A preferred method of making the puffed food starch product of the present
invention,
illustrated in FIGURE 18, utilizes a bulk amount of a previously described
food starch. The disclosed
method begins by providing a puffing chamber having inner surfaces and a
chamber volume, and then
placing a bulk amount of the food starch material into the puf~rng chamber.
Generally speaking, the
bulk amount of food starch is caused to volumetrically expand. In other words,
the bulk food starch
is puffed to several times its original size.
Puffing machines (usually having a plurality of chambers each) are widely
known and
understood by those skilled in the art. A suitable puffing machine is
manufactured by REAL FOODS
CA 02346964 2001-05-11
13
PTY, LTD. of St. Peters NSW, Australia. Referring to FIGURES 1-6, puffing
chamber 20 is shown,
generally, having an opening 21 on ring mold 22, upper mold insert 24
(attached to an upper base 25),
and lower mold insert 26 (attached to a lower base 27). Each of these
components may be slidably
movable on guide pins 28, though ring mold 22 is typically fixed. The mold
inserts 24, 26 (via bases
25, 27) may be actuated hydraulically, pneumatically, or in any other suitable
manner. As shown in
FIGURES 2 and 3, mold insert 24, 26 enter opening 21 to form the inner
surfaces of the pufEng
chamber.
The present preferred method requires constraining the expansion of the bulk
amount of food
starch in at least a first dimension, while permitting expansion of the bulk
amount in at least a second
dimension. In other words, the food starch is capable of expanding to its full
volumetric potential
(taking into account moisture content of the food starch, temperature of the
chamber, and the forces
of gravity), while being prevented from expanding in one of either height,
width, or depth. For
example, if the height of the puffed product is constrained, then the width
and depth of the puffed
product proportionately increase. Where two dimensions are constrained, the
third will compensate
to achieve total volume expansion. At no time is the total volumetric
expansion ofthe puffed product
constrained by the inner surfaces of the puffing chamber, while dimensional
expansion is constrained.
Preferably, this may be achieved by predetermining the proper amount of the
bulk amount of food
starch placed into the puffing chamber relative to the total volume of the
chamber in an unsealed
(puffing) condition Prior art processes attempt to completely fill the chamber
(at least upon puffing).
Using the puffing chamber for dimensional constraining may be achieved by
defining a general
shape of the product (as discussed previously) in the first dimension, or in
both the first and third
dimensions. The constrained shape may be provided by, in one particular
embodiment, constraining
expansion with the inner surfaces of the puffing chamber.
Balanced against the unconstrained volumetric expansion aspects ofthe present
invention (i. e.,
properly sizing the bulk amount of food starch placed into the puffing
chamber) is the necessity to
produce a single, unitary product from the puffing chamber. With these
competing interests in mind,
the present method may further include predetermining the bulk amount of food
starch to be placed
into the chamber, such that there is a sufficient amount of whole kernels or
pellets (or corn grits) that
CA 02346964 2001-05-11
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all of the kernels or pellets (and grits) touch at least one other kernel or
pellet (or grit) after becoming
amorphous.
While the exact mechanism of how the food starch bonds together in the puffing
chamber is
not fully understood, refernng to FIGURE 20, it is believed that a melt
occurs, or at least a softening
or gelatinization of the food starch. In a preferred embodiment of the
invention, the puffing chamber
20 is heated to a temperature of about 475°F (about 246°C).
Puffing machines, as well as individual
puffing chambers, however, can vary greatly from one to another. Due to such
differences, and any
other prevailing conditions which may exist (e.g., the amount and type of food
starch and its
preprocessing history), the chamber temperature may range from about 3
50°F (about 177°C) to about
550°F (about 288°C), including any combination or sub-
combination of ranges within this range. As
the chamber is sealed and the food starch is heated, the internal pressure of
the chamber increases,
though a final pressure has not been measured. No additional pressure is added
to the chamber in the
preferred embodiment, but may be implemented for alternative embodiments.
Referring to FIGURE 7, a supply plate 30 is shown. Supply plate 30 is shown
having seven
(7) openings 32, but may contain more or less to suit particular manufacturing
needs. Openings are
preferably about 0.563 inches diameter by about 0.591 inches deep (about 0.147
cubic inches) to
allow a sufficient amount of bulk food starch to pass through for puffing an
approximately two inch
(2") product, but these dimensions may vary for larger or smaller products.
The volume of opening
32 determines the amount of food starch to be added to each chamber. Each
opening 32 corresponds
to a chamber 20 of the puffing machine. As supply plate 30 moves across the
open ring mold 22, it
deposits the predetermined amount of bulk material filling each opening volume
into the chamber 20,
to rest on lower mold insert 26. Supply plate 30 is then retracted.
The chamber is closed as shown in the sequence of FIGURES 2-5, and the bulk
food starch
is heated to an amorphous or extensible state. After an approximate 5.25 to
6.75 second heating cycle
time, upper mold insert 24 raises to release pressure in chamber 20, as shown
in FIGURE 4. Then
upper mold insert 24 completely raises and lower mold insert 26 raises to
become flush with the upper
surface of ring mold 22, as shown in FIGURE 6. Finally, supply plate 30 return
to make a subsequent
deposit, pushing the puffed food starch products to a discharge chute (not
shown) in the process.
CA 02346964 2001-05-11
The amount of food starch used in the present invention is less than that used
in prior art
processes. A relationship exists between the mass of food starch used and the
expansion of the final
product, also taking into consideration the chamber volume (about 0.79 cubic
inches in the present
invention), cycle time, and chamber temperature. Basically, the expanded food
starch should not be
5 constrained by the chamber volume, as discussed above. Another
consideration, however, is the
placement of the food starch within the chamber. If the food starch is thick
or mounded on top of
itself, then expansion ofthe food starch as a whole will be diminished. Thinly
spread food starch will
tend to puff more completely.
Where pellets are used in the present invention, it is considered to be within
the knowledge
10 ofthose skilled in the art to prepare suitable pellets. The J. R. SHORT
COMPANY, Chicago, Illinois,
manufactures such a rice pellet. Basically, referring to FIGURE 19, beginning
with a floured food
starch, the starch is gelatinized in an extruder under a pressure and
temperature. The food starch is
then extruded and cut, forming individual pellets. The pellets, in the
preferred embodiment, are
formed generally to the size of a whole kernel of grain. The grain size can be
selected from the group
15 of grains including rice, wheat, barley, oats, rye, corn, etc. The extruded
food starch pellets may be
cooled sufficiently (i.e., slowly) to substantially reduce any stress in the
pellet, and to provide
sufficient drying to provide good shelf life and prevent extruded food starch
pellets from sticking
together in storage.
In another preferred embodiment of the present method, Applicant found
advantages in
pelletizing the food starch material , and then placing an amount of the
pelletized food starch into the
puffing chamber. The amount may be as little as a single pellet, or as many as
suitable for the chamber
size. The pellets within the chamber are then caused to volumetrically expand
and form a suitable
cake or chip.
Another major advantage of the use of pellets over whole kernels is that the
pellets need not
be tempered prior to puffing. That is, tempering is a process whereby the
whole kernels are tumbled
in a high moisture atmosphere (frequently steam is used). This is not
necessary for pellets. The
moisture content of the pellets is controlled at manufacture, most preferably
within the range of about
10% to about 12% (by weight). Additionally, the tempering process is used to
increase the puffability
CA 02346964 2001-05-11
16
of the kernels, as described above. Pelletization appears to provide
sufficient enhancements to
puffability to negate the need for tempering.
While specific embodiments have been illustrated and described, numerous
modifications are
possible without departing from the spirit ofthe invention, and the scope of
protection is only limited
by the scope of the accompanying claims.
