Patent Application
20100143549
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. More particularly, the present invention relates to unique, modular pods designed for use with the aforementioned methods and apparatus.
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.
Health conscious consumers depend on major commercial food manufacturers to provide freshness and balanced nutrition in their breakfast cereals. Unfortunately, due to the high-shear processes used in producing these cereals and the addition of preservatives for the purpose of increasing shelf life, the health, freshness and nutrition aspects of the food suffer greatly.
This invention provides a method for conveniently producing freshly made highly nutritious, breakfast cereals to the health conscious home consumer by means of a low-shear extrusion process. This invention will further provide a method for conveniently producing freshly made and highly nutritious snack and pet foods, also in the home environment. In the pet food application, the invention provides an improved nutritional value over commercially sold pet food, avoidance of uncontrollable portions experienced with bulk quantity food, and elimination of the need for large bag purchase and storage.
Additional applications of the invention can include, but are not limited to: Pasta Extruder and Crouton Extruder.
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.
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.
In prior art devices, food ingredients are continuously fed into a process chamber which often incorporates a continuously spinning auger, upwards of 100 feet long. The auger mixes the ingredients, generates heat and pressure within the chamber and advances the mixed food material towards the discharge nozzle at the end of the chamber. Differential between the interior chamber pressure and the exterior chamber pressure (atmospheric) causes the mixed/heated food material to discharge through the nozzle. As the food material exits the nozzle, it expands and is cut to desired lengths by means of rotating blades. Expansion occurs as a result of flashing (instant boiling) of most of the water content within the food material upon exposure to atmospheric pressure outside of the process chamber. Expansion rate is controlled by regulating the moisture and starch percentages of the food material prior to exit through the nozzle. After the discharged food material is cut, it is transported to a baking chamber where it is dried to a moisture content of approximately 8 percent. The drying process in combination with added chemical preservatives prevents bacterial growth, thereby, increasing shelf life of the final food product.
The heat required for the prior art processes is generated as a result of friction developed between the auger and the food material. In addition, some of the food material is ground between the auger and chamber wall. These actions cause high shear within the food material, thereby destroying a large percentage of its nutrient and starch contents.
Chemical preservatives are added to the food product, making that product capable of being stored in warehouses and on store shelves for prolonged periods of time. Given the choice, today's health conscious consumers prefer food products that are freshly made and free of chemical preservatives.
Also prior art pet food products are either supplied in pre-cooked condition, whether in bulk or individually packaged portions, or in raw food condition, only available through niche markets and at a more expensive price point. Consumers have thus sometimes been compelled to substitute human food for their pets to achieve the desired nutritional value and freshness.
The prior art cited during the prosecution of the parent application does not disclose the invention covered by the instant patent application:
The elements disclosed by the instant patent application and for which patent protection is being sought, that are neither disclosed by nor rendered obvious in view of prior art, are unique pods for a home kitchen appliance designed and sized for use on a kitchen counter or in a pet feeding area, for conveniently producing single and/or multiple servings of nutritious, freshly made food products. The pods are used in an appliance that performs the processes of mixing, baking and extruding grain based ingredients in a form that provides a nutritionally sound food, in individual serving sized portions.
The food ingredients used for producing food products in accordance with the present invention are purchased separately as a pre-formulated and pre-mixed batch that is sealed inside a pod constructed with an integrated extrusion nozzle. In the pet food application, pods are formulated and sized according to specific daily nutrition requirements of end use animals, which is beneficial to portion control and weight management.
The appliance utilized with the unique pods is designed to perform the process of food preparation in a few minutes, utilizing a combination of pre-mixed ingredients in the pod with no preservatives or artificial ingredients. The process permits a “no muss, no fuss” production and clean up.
Other novel features that are disclosed include:
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.
In another embodiment, the invention relates to a compact pet food production apparatus targeted for the consumer (home use) market that can be placed in the customary pet food feeding area.
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.
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.
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.
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.
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.
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, pre-stressed or pre-gelatanized 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.
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.
In yet another aspect of the invention, each batch of ingredients is sealed in a pod that has a moisture percentage that is low enough to prevent bacterial growth and rancidity during pod storage. If the finished food product requires fat, e.g., for nutritional value, or if it requires flavorings or seasonings, these can be stored in a reservoir in the pod or outside the pod. The pod is placed in the compression module of the apparatus for processing.
In yet another aspect of the invention, individual pods can have an attached bar code that contains processing parameters unique to the intended finished food product in the particular pod and which bar code is read by the appliance's control system at the beginning of the process in order to convey the requisite processing parameters to the compression module and drying module of the appliance.
In yet another aspect of the invention, the pod contains premixed dry ingredients and water is introduced into the premixed dry ingredients, either from a water blister within the pod that is mechanically burst or pierced, or from a water reservoir outside of the pod.
In yet another aspect of the invention, the dry ingredients and water are mixed within the pod by a combination of timed vibration at controlled frequencies and mechanical manipulation, or by heating the water and resultant steam migration.
In yet another aspect of the invention, the pod is pressurized while the food mixture is heated, and then the pressure is increased and the pod nozzle is opened and the food material is extruded out the nozzle, causing the food material to expand as a result of flashing (instant boiling) of most of the water content within the food material upon exposure to atmospheric pressure outside of the pod nozzle, before it is cut into desired sizes.
In yet another aspect of the invention, once the food ingredients within the pod have been processed by the appliance and the food material has been extruded from the pod, the pod is simply removed from the appliance and discarded.
The invention is unique in that:
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.
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:
a and 13b are two views of a preferred embodiment of a pod constructed in accordance with this invention, namely, a multi-piece pod construction with an internal water blister and an integrated flexible extrusion nozzle.
a, 14b and 14c are three views of an alternative embodiment of a pod constructed in accordance with this invention, namely, a multi-piece pod construction with an internal water pouch, an internal fat pouch and an integrated rigid extrusion nozzle.
a, 15b and 15c are three views of an alternative embodiment of a pod constructed in accordance with this invention, namely, a multi-piece pod construction with a single supply of dry food ingredients in an annular ring chamber, a single water pouch, multiple fat pouches and multiple extrusion nozzles.
a and 16b are two views of an alternative embodiment of pods constructed in accordance with this invention, namely, a multi-piece pod construction with a single supply of dry food ingredients in an annular ring chamber, an integrated extrusion nozzle and a compression plate for forcing processed food material through the extrusion nozzle. In the embodiment shown in
a and 17b are two views of an alternative embodiment of a pod constructed in accordance with this invention, namely, a multi-piece, pod with a flexible side wall construction, separate dry food ingredient and water pouches and an integrated extrusion nozzle.
a and 18b are two views of an alternative embodiment of a pod constructed in accordance with this invention, namely, a multi-piece pod, with a semi-rigid side wall construction, separate dry food ingredient and water pouches and an integrated extrusion nozzle.
a and 19b are two views of an alternative embodiment of a pod constructed in accordance with this invention, namely, a multi-piece pod, with a rigid side wall construction, with a dry food ingredient chamber into which water is injected by the appliance during processing, an extrusion nozzle and a compression plate for forcing processed food material through the extrusion nozzle.
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, or (unless expressly stated otherwise) to any specific pod shape or pod material.
The compression module includes the components listed and arranged as shown in
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 101 of the compression module 100 and the chamber cover 102 is attached and sealed to the chamber and locked. The heating element 103 is activated to begin the cooking process. As the closed-volume cooking process proceeds, the pressure and boiling point of the food materials continuously elevates 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 104 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.
Once the pressure of the food materials within the chamber reaches a pre-determined level, the nozzle or valve 105 opens, allowing the pressurized food material to flow from the chamber out the discharge tube 106. 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 dependent 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.
The expanded food product flowing from the compression module nozzle 105 out the discharge tube 106 optionally enters the dryer module 200 through an opening 201 in the enclosure wall 202 thereof. After exiting from this opening, the food product is cut into equal length sections by a spinning blade 203. 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 203. 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.
After being cut, the food sections are gravity fed into a perforated holding bin 204. Once the complete batch of food product has been sectioned and is in the holding bin 204, a heater 205 and a blower unit 206 are both activated. In one embodiment, the heater 205 is located directly beneath the holding bin 204 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 206 is located directly beneath the heater 205, 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 204 during the drying/toasting process.
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 101 having a diameter from about 0.25″ to about 4″ is used. The piston 104 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 100, the cylinder 101 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.
One of the considerations when selecting the size of the cylinder 101 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 104 stroke, the production rate will remain constant. Each shot will have ¼ 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.
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″ piston with a hollow 3″ piston 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″ piston. 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.
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.
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.
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.
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.
The following test data is included to be illustrative only.
Referring now to
Referring now to
Dimensionless Format: Referring now to
where: Ti=initial temperature
UTC goes from 1 to zero at infinite time.
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.
Various embodiments of pods that fall within the scope of this invention are shown in
The preferred embodiment pod 401, disclosed in
An alternate embodiment pod 501, disclosed in
An alternate embodiment pod 601, disclosed in
An alternate embodiment pod 701, disclosed in
The alternate embodiment pod 801, disclosed in
The alternate embodiment pod 901, disclosed in
An alternate embodiment pod 1001, disclosed in
The pods shown in
Each batch ingredient has a moisture percentage that is low enough to prevent bacterial growth and rancidity during pod storage. Optionally, the ingredient batch can be:
If the finished food product requires fat for nutritional value:
Individual pods may have an attached bar code containing process parameters (mix time, pressure, temperature, extrusion velocity, cutter speed, etc.) unique to the intended finished food product. The code is read by the appliance's control system at the beginning of the process, as more fully described herein below.
The following is a generic description of the process. Process parameters would be adjusted depending on food ingredients:
Process and extrusion pressures are generated and maintained by decreasing/increasing the closed volume of the process chamber in which the pod is placed. This can be accomplished with:
Process and extrusion pressures are confirmed by:
Process heat is generated with:
Process temperatures are confirmed by:
The pod nozzle opens when:
The discharging/expanding food material is cut by:
Food expansion occurs as a result of flashing (instant boiling) of most of the water content within the food material upon exposure to atmospheric pressure outside of the pod nozzle. Expansion rate and final moisture content are controlled by regulation of the initial moisture and starch percentages of the pre-formulated ingredient batch within the pod.
The invention can be used for producing a variety of freshly made and nutritiously balanced foods including but not limited to:
Each food type has unique characteristics in palatability, texture and density which result from pressure and temperature being specifically applied to its original moisture and starch contents during a specified cooking time. Moisture and starch contents vary from food type to food type. *Thus, required pressure and temperature values vary as well, but are within the ranges shown in the following process methods. The food's flavor is primarily determined by the base ingredients of the food recipe. Each food type can be produced by one or either of two processing methods, described below.
(Ranges shown accommodate processing of various food types)
(Ranges shown accommodate processing of various food types)
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.
This continuation-in-part application claims priority to and the benefit of U.S. provisional patent application Ser. No. 60/672,902, filed Apr. 19, 2005, and of U.S. parent application Ser. No. 11/407,386, filed Apr. 19, 2006, the entire disclosure of both of which is hereby expressly incorporated herein by reference. Applicant is also concomitantly filing an additional continuation-in-part application based upon the above-identified common U.S. parent application, and applicant hereby expressly incorporates herein by reference the entire disclosure of such concomitantly filed continuation-in-part application.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 11407386 | Apr 2006 | US |
| Child | 12454969 | US |
