This invention relates to a laminated wrapper for use in cook-in food preparation. The hand-molded integral packaging wrapper when placed around food items or cooking containers prior to cooking provides uniform heat distribution, minimizes or prevents cook-out, can be peeled from the food product after cooking without tearing away portions of the surface of the food product, provides a strong tear resistant wrapper, reduces the risk of aluminum toxicity, and which may facilitate the transfer of a modifier to the food product during the cooking process and will provide a barrier between the food and cooking container. According to one preferred embodiment of the invention, the wrapper comprises a lightweight parchment or similar type of paper laminated to aluminum foil with a food grade adhesive system. The aluminum foil provides uniform heat distribution, minimizes or prevents cook-out and provides the ability to mold the wrapper onto the food surface or cooking container. The parchment paper provides ready release from the food surface, overall strength to the wrapper and provides barrier from the aluminum foil. The subject wrapper can also be prepared with a modifier absorbed into the paper to impart colorants, odors or flavors to the food product. The modifier is transferable from the paper to the receiving surface of the food product by fluid contact.
Numerous prior art patents disclose multilayer or coated films which heat shrink to fit the food. Typically these food products are prepared utilizing manually molded packaging which includes individual sheets of parchment paper overwrapped with aluminum foil. Wrappers for packaging must be structurally capable of withstanding exposure to heat during cooking time and temperature conditions while containing the food product. Cooking time and temperature conditions may vary dramatically. Parchment paper used by itself should not touch open flame, be used under a broiler, in toaster ovens or halogen light ovens. Parchment paper generally withstands temperatures up to 420 F. (215 C.) Aluminum foil has heat resistance properties sufficient for most commercial or home ovens <550 F. (<288 C.) Aluminum foil used in conjunction with parchment paper as an overwrap allows the wrapper package to withstand most time and temperature conditions.
Prior to the cooking process, the wrapper package should be substantially conformed to the shape of the contained food product. The wrapper should also possess sufficient product adherence to restrict or prevent “cook-out,” i.e., loss of juices from between the surface of the contained food product and the food-contact-surface of the packaging material during cooking, thereby increasing product yield and providing a better-tasting moist food.
Conventional pan liners typically consist of a parchment paper, with excellent release capabilities, placed in the bottom of a tray, pan or dish where the food ingredient contents are then baked or broiled. Unfortunately paper pan liners cannot be conformed to the shape of the tray, pan or dish, thereby allowing cooking liquids to migrate under the liner and contaminate the cooking container. Aluminum foil laminated to parchment paper as a pan liner allows the wrapper to conform to shape of the tray, pan or dish, preventing contamination of the cooking container.
Conventional wrappers possess a number of undesirable drawbacks. Parchment paper alone does not provide sufficient adherence to the surface of the food product or cooking container to prevent cook-out or container contamination. In other words it is not moldable. This results in reduced product yield, non-uniform heat distribution and poor taste or cooking container contamination. Aluminum foil successfully prevents cook-out and cooking container contamination, but typically may adhere to the surface of the food product with such adhesive strength that portions of the food product are torn away from the remainder of the food product when the foil is peeled from the food product after cooking. That is, the cohesive force within the food product is overcome by the adhesive force between the foil and the surface of the food product. As a result, product yield is reduced and the food product has an unsightly (pitted) surface-appearance. Aluminum foil is also susceptible to tearing. A tear may result in the loss of barrier for the food during cooking or may result in a piece of aluminum foil being adhered to the food which then may be ingested if not removed.
Aluminum from aluminum foil is generally known to migrate into food surfaces imparting a metallic taste and increased risk of aluminum toxicity. Aluminum is not a heavy metal, but it can be toxic if present in excessive amounts—even in small amounts, if deposited in the brain. Many of the symptoms of aluminum toxicity are similar to those of Alzheimer's disease and osteoporosis. Aluminum toxicity can lead to colic, rickets, gastrointestinal disturbances, poor calcium metabolism, extreme nervousness, anemia, headaches, decreased liver and kidney function, forgetfulness, speech disturbances, memory loss, softening of the bones, and weak, aching muscles.
Research indicates that the longer that you cook food in aluminum, the more it corrodes, and the more aluminum compounds migrate into food and are absorbed by the body. Aluminum is more readily dissolved by acid-forming foods, such as cheeses, meats, cabbage, cucumbers, tomatoes, turnips, spinach, and radishes.
It is often desirable to apply a modifier to the outer surface of the processed food product. For example, if the food product is poultry, beef or ham, it may be desirable to impart smoke color, flavor, and odor to the outer surface of the food product. This is often accomplished by applying “liquid smoke” to the outer surface of the food product during or after cooking. It would be desirable for the wrapper to allow smoke color, flavor, and odor to be transferred to the poultry, beef or ham during the process. In general, a wrapper can apply a modifier which imparts colorants, odors or flavors to the food product would be desired.
Accordingly, a need exists in the art for a food packaging which incorporates both parchment paper and aluminum foil by lamination into an integral packaging wrapper. The integral packaging wrapper is hand-molded when placed around food items or cooking containers prior to cooking, and provides uniform heat distribution, minimizes or prevents cook-out, can be peeled from the food product after cooking without tearing away portions of the surface of the food product, provides a strong tear resistant wrapper, reduces the risk of aluminum toxicity, and which may facilitate the transfer of a modifier to the food product during the cooking process.
Therefore, it is an object of the invention to provide a laminated wrapper within which food items may be contained and cooked.
It is another object of the invention to provide a laminated wrapper within which food items may be contained and cooked, and having both a paper and metallic foil component, each of which provide enhanced cooking features.
It is another object of the invention to provide a laminated wrapper within which food items may be contained and cooked, wherein a metallic component is separated from the food by a paper component.
It is another object of the invention to provide a laminated wrapper within which food items may be contained and cooked, and which includes an edible film layer containing substances that impart flavor, odor and/or color to the food being cooked.
Paper, in the form of “boxboard” or “paperboard,” has been widely used for such disposable items as dining cups and containers for liquids, such as milk and fruit juices. For these applications, paper has the advantages of low toxicity, low cost, printability, biodegradability, and the ease with which it may be formed into the required shapes. However, untreated paper is not suitable for the aforementioned applications, because it is permeable to water and other aqueous and non-aqueous fluids.
It is well known in the art to coat materials and substrates with a fluorochemical coating, in order to impart oil and grease resistance to the materials and substrates. For example, Schwartz, “Oil Resistance Utilizing Fluorochemicals,” TAPPI, Seminar Notes, 74, 71-75 (1987) discloses the use of commercially available FDA-cleared fluorochemicals to impart resistance to low surface tension fluids on various substrates.
U.S. Pat. No. 4,426,466 discloses treatment compositions containing fluorochemical carboxylic acid and epoxidic cationic resin to impart oil and water repellency to cellulosic materials. U.S. Pat. No. 4,529,658 discloses fluorochemical copolymers useful for imparting oil and water repellency to cellulosic and textile materials. U.S. Pat. No. 5,370,919 discloses fluorochemical compositions for imparting oil and water repellency to various substrates.
U.S. Pat. No. 5,603,996, to Overcash et al. discloses a coated sheet material that includes a porous cellulose substrate sheet material, having a barrier coating thereon which is a blend of a cross-linkable polymer that is resistant to penetration by water moisture when cured and a water-dispersible, film-forming polymer that is resistant to penetration by grease and oil when cured. Disposed on the barrier layer is a release coating, which consists of a fatty acid complex of a metal ion, which is cross-linked to the film-forming polymer in the barrier layer.
Another approach has been to coat a mixture of polyvinyl alcohol and a chrome-fatty acid complex, such as Quilon.RTM., onto a paper substrate. Quilon.RTM., manufactured by the DuPont Company, is a dark, blue-green, chemically reactive, Werner complex in which a C14-C18 fatty acid is coordinated with trivalent chromium in isopropanol solution.
Another approach is to utilize silicone to impart easy and clean release to paper is applied on a gravure coater off line to a typical fourdrinier wet laid paper machine. The base paper used for silicone treatment requires a high level of cellulose fiber refining and calendering in order to achieve a very tight sheet pore structure (as measured by air porosity). The subject base paper is typically a supercalendered kraft paper or glassine type product.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a packaging material for forming a cook-in food package, comprising an aluminum foil sheet for providing uniform heat distribution and moldable conformity of the material to a food being cooked or cooking container, a paper sheet for directly contacting the food and providing a non-stick, releasable food contacting surface and a barrier between the food and the aluminum foil sheet, and a food grade adhesive applied between the aluminum foil sheet and the paper sheet and bonding the aluminum foil sheet and paper sheet together to form a lamination thereof. The adhesive used to laminate the aluminum foil sheet and paper sheet together should be food grade having adequate ductility and elasticity for desired lamination properties.
According to one preferred embodiment of the invention, the adhesive comprises a water-based high temperature acrylic with low vapor emission.
According to another preferred embodiment of the invention, the adhesive comprises a solvent-based high temperature acrylic with low vapor emission.
According to another preferred embodiment of the invention, the adhesive comprises a 100% solids-based high temperature acrylic with low vapor emission.
According to another preferred embodiment of the invention, the adhesive comprises an extruded high temperature acrylic or polyolefin with low vapor emission.
According to another preferred emobdiment of the invention, the adhesive comprises a water-based, solvent-based, 100% solids-based high temperature casein with low vapor emission.
According to another preferred embodiment of the invention, the packaging material includes an edible coating or film applied to the paper for contacting the food during cooking, and a modifier carried by the film for modifying the food during cooking, the modifier selected from the group consisting of colorants, odorants, flavorants, antioxidants, antimicrobial agents, enzymes, odor absorbents, and blends of the foregoing modifiers.
According to another embodiment of the invention, the edible coating or film is a film formed from a material selected from the group consisting of cellulose ether, starch, hydroxypropylated starch, corn zein, wheat gluten, soy protein, milk proteins, or pureed fruits and vegetables.
According to yet another preferred embodiment of the invention, the paper comprises parchment.
According to yet another preferred embodiment of the invention, the paper comprises a silicone-coated, grease-proof paper.
According to yet another preferred embodiment of the invention, the packaging material is formed into a structure selected from the group consisting of pouches, trays, pan liners, tents, wraps, and lids.
According to yet another preferred embodiment of the invention, a cook-in food package is provided, comprising an aluminum foil sheet for providing uniform heat distribution and moldable conformity of the material to a food product being cooked, a paper sheet for directly contacting the food and providing a non-stick, releasable food contacting surface and a barrier between the food and the aluminum foil sheet, and a food grade adhesive applied between the aluminum foil sheet and the paper sheet and bonding the aluminum foil sheet and paper sheet together to form a lamination thereof that is manually-moldable into a shape conforming to the shape of the food product or cooking container to be cooked.
According to yet another preferred embodiment of the invention, the paper sheet comprises a non-stick silicone-coated sheet.
According to yet another preferred embodiment of the invention, a cook-in food container is provided, comprising an aluminum foil sheet for providing uniform heat distribution and moldable conformity of the material to a food product being cooked, a paper sheet for directly contacting the food and providing a non-stick, releasable food contacting surface and a barrier between the food and the aluminum foil sheet, a food grade adhesive applied between the aluminum foil sheet and the paper sheet and bonding the aluminum foil sheet and paper sheet together to form a lamination thereof. The resulting laminate is formed into a container adapted for containing a food product during cooking.
Some of the objects of the invention have been set forth above. Other objects and advantages of the invention will appear as the invention proceeds when taken in conjunction with the following drawings, in which:
Referring now specifically to the drawings, a laminated paper and aluminum foil food product wrapper according to the present invention is illustrated in
A preferred embodiment of the adhesive 13 useful in this application is a water-based acrylic, casein or a plastics material such as polyester or other temperature-resistant polymer with low vapor emission (EVA). The adhesive used to laminate the aluminum foil sheet and paper sheet together should be food grade having adequate ductility and elasticity for desired lamination properties. These adhesives may be applied as water-based, solvent-based or 100% solids-based systems. The plastics material may be applied by extrusion coating. While the laminate construction is proposed by standard lamination manufacturing procedures, it should be understood that the present invention can be constructed using any known technique, including heat seal, thermal bonding and sonic sealing.
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While the application of the adhesive formulation has been discussed above in the context of a lamination, it should be understood that the methodology for adhering the paper 12, 22 to the foil 11, 21 as disclosed in the present invention can be applied to either one of the materials using any known technique, including application by paper mills at a size press or calender stack. It may also be applied by converters via rotogravure, flexographic, blade, air knife, spray and other like coating equipment.
The cooking sheet 20 also includes an edible film 24 laminated to the surface of the paper 22 opposite the surface bonded to the aluminum foil sheet 21, and which contains a material to be transferred by contact to the food during cooking. The edible film 24 may be formulated from, for example, cellulose ether, starch, hydroxypropylated starch, corn zein, wheat gluten, soy protein, milk proteins, or pureed fruits and vegetables. Examples of modifiers which can be transferred to the food product via the edible film 24 during cooking include colorants, odorants, flavorants, antioxidants, antimicrobial agents, enzymes, odor absorbents, or blends of the foregoing materials.
The variety of food product wrappers with which the construction of the present invention can be used to provide an enhanced enclosure is substantial. For example, the present invention can be used to provide food product wrappers which are hand or commercially molded into lidding, pouches, trays, tents and wraps which may incorporate the use of metal glass or plastic pots, pans, trays or dishes.
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The laminated wrapper within which food may be cooked is further explained with reference to the following examples:
24# Silicone Grease Proof (GP) paper w/wet strength was patterned and laminated to a 0.00285 mil, 12.0# Aluminum Foil (#/3000 ft2) Aluminum Foil Laminate. A high temperature (+450 F, +232 C) acrylic adhesive was applied to the GP paper utilizing a commercial gravure coater. The adhesive coating pattern was applied in the shape of a hexagon with 1.0 centimeter per side. The laminate thus prepared was used to prepare potatoes, asparagus and chuck roast. Samples were tested as follows:
1. Prepared: Baked Potato.
2. Prepared: Baked Potato.
3. Prepared: Oven Roasted Asparagus.
4. Prepared: Chuck Roast.
The GP paper was much easier to work with than parchment paper, i.e.; more flexible and the cooking liquid & butter grease did not burn onto the paper as it would with a parchment grade. Under no condition did the GP paper tear or leak.
The next step was to prepare the full surface laminate.
24# Silicone Grease Proof (GP) paper w/wet strength was full side laminated to a 0.00285 mil, 12.0# Aluminum Foil (#/3000 ft2) Aluminum Foil Laminate. A high temperature (+450 F, +232 C) acrylic adhesive was applied to the GP paper utilizing a commercial gravure coater. The adhesive coating was a full side application. The laminate thus prepared was used to prepare sirloin roast. Samples were tested as follows:
5. Prepared: Sirloin Roast.
The Exhibit B product provided a satisfactory product. The solid lamination is tightly bound with good aesthetics prior to cooking. The product's clear adhesive with aluminum foil show through to the bright GP paper represents a feel of cleanliness and snap. The only delamination occurred where the aluminum foil was cracked or pealed. GP paper remained intact and did not leak. The product aluminum foil weight is adequate for pan liners and other structures where high moldability or wrapper stressing is not required.
The product did not “dead fold” adequately. It is more difficult to seal a casserole dish, hand pattern a tray, or produce a cooking pouch. A heavier aluminum foil layer with no other changes appears desirable, for example a full surface laminate using 0.00035 mil (14.7#) aluminum foil.
24# Silicone Grease Proof (GP) paper w/wet strength was full side laminated to a 0.0035 mil, 14.7# Aluminum Foil (#/3000 ft2) Aluminum Foil Laminate.
Based on the foregoing examples, an aluminum foil layer 0.0035 mil, 14.7# Aluminum Foil (#/3000 ft2) or heavier provides improved strength and dead fold at minimum foil weight. Layer weights used for standard commercially available aluminum foil 0.0065 mil, 27# Aluminum Foil (#/3000 ft2) or heavier can be laminated and will perform equally well in use testing. The economics favor the use of a lighter weight 0.0035 mil, 14.7# Aluminum Foil (#/3000 ft2) layer.
Numerous variations can be made on the 24#/3000 ft2 Silicone Grease proof (GP) paper. Standard parchment papers with either PFOS, Quilon or numerous other grease proof additives can be utilized. Also the basis weights of the GP paper can range from 20# to 27#/3000 ft2 with no adverse effects. Grease Proof (GP) Discussion from applicant's United States Patent Application: 20040005341 may also be suitable.
A laminated cook-in food package is described above. Various details of the invention may be changed without departing from its scope. Furthermore, the foregoing description of the preferred embodiment of the invention and the best mode for practicing the invention are provided for the purpose of illustration only and not for the purpose of limitation—the invention being defined by the claims.
This application claims the benefit of Provisional Application No. 60/486,976, filed on Jul. 14, 2003.
Number | Date | Country | |
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60486976 | Jul 2003 | US |