COMPOSITION FOR USE IN EDIBLE BIODEGRADABLE ARTICLES AND

METHOD OF USE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application Serial No.

11/285,508, filed November 21, 2005, which is a continuation-in-part of U.S. Patent

Application Serial No. 10/928,602, filed August 26, 2004, which claims priority to

Provisional Application Serial No. 60/498,396, filed August 27, 2003, all of which

are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Field of the Invention

[0002] The invention generally relates to a mix formulation for the production

of edible, biodegradable, and compostable food packaging and service items and

methods for use of said formulations.

Background

[0003] Conventional disposable food service items are commonly made from

paper or paperboard (commonly coated or impregnated with a polymeric water¬

proofing material such as wax or polyethylene), or one of a variety of plastics

(polystyrene is the most common). In addition, ovenable disposables are made from

aluminum or CPET, commonly known as dual ovenable plastic.

[0004] During the introduction of Biosphere biodegradable compostable

products, it was found that children often expressed a desire to eat the articles

presented. When asked, adults also expressed an interest in edible packaging or

food-service items. Edible, starch-based food service items which were greeted with

considerable public enthusiasm at the 1994 Winter Olympic Games in Lillehammer,

Norway; after use, those items were fed to livestock, eliminating a large source of

waste. Home and industrial bakers have expressed a desire for edible molding

devices for cakes, cupcakes, muffins, tarts, pies, and the like, to replace the metal and

paper items currently in use.

[0005] In addition to the intrinsic appeal of edible packaging materials to

children and other consumers, there is a growing recognition that the environmental

costs of using "cheap" plastic materials for packaging may be quite high. The

expected lifetime of a polystyrene cup, for example, is about 500 years, and each

American disposes an average of about 100 cups per year. Polystyrene is made by

chemical processing of benzene and ethylene, both byproducts of the petroleum

industry, and thus both nonrenewable resources. Although the environmental record

of the petroleum industry has improved greatly since the mid-twentieth century,

extraction and processing of petroleum for fuel and chemical production remain

recognized environmental problems. Questions have also been raised about the

wisdom of using a limited natural resource (fossil hydrocarbon stocks) to produce

disposable items (which exacerbate waste handling problems) rather than reserving

the resource for production of durable goods.

[0006] United States Government sources indicate that packaging (of all types)

makes up 32 percent of the municipal solid waste stream by weight. Food packaging

makes up about 9 percent of the waste stream. Costs of disposal of municipal wastes

are likely to increase as landfill regulations become more stringent, current sites are

filled and replaced by (usually) more distant sites, and waste transportation costs

increase (along with fuel costs).

[0007] Pet food packaging also contributes appreciably to the waste stream.

The total annual worldwide market for pet food packaging has been estimated to

exceed $500 million, with increasing emphasis on smaller packaging, including

portion-sized packages. As in all industries, the smaller the quantity of product per

unit sold, the greater the ratio of packaging volume to product volume; the quantity

of pet food packaging being used is thus growing at a higher rate than the quantity of

pet food itself.

[0008] Materials that are impervious to moisture and impermeable to oxygen

and other gases include conventional plastics, metals, glass, and plastic-coated paper

or paperboard. Of these, metal, glass, paperboard, and molded plastics typically

provide structural protection of the packaged items as well as barrier properties,

whereas plastic films and plastic-coated papers mainly provide barrier protection

rather than structural protection. Typically much more mass is required to obtain the

structural rigidity required of packaging than is required to obtain suitable barrier

properties alone. None of these materials are biodegradable or compostable. To the

extent that they enter the disposal waste stream (i.e., that they are not recycled), these

materials are persistent; they will remain in landfills even where oxygen and moisture

are provided to encourage biodegradation.

[0009] In addition to waste disposal concerns, some current research suggests

that certain chemicals (phthalates and other plasticizers) used in the manufacture of

plastics may have detrimental effects on the environment and on human reproductive

systems, even at extremely low concentrations, by affecting the endocrine (hormone)

system in humans and many other animal species. The observations suggest that, in

both wildlife and humans, very low concentrations of these compounds can mimic or

interfere with hormones that play important roles in embryonic development,

resulting in effects such as hermaphroditism in gastropods; feminization of fish,

alligators, and some mammals; malformations or morbidity in amphibians, fish, and

birds; and various effects in human developmental and reproductive biology.

Although the research and many of the conclusions that have been drawn from it are

controversial, the FDA and some Japanese and European regulatory agencies are

considering bans or additional regulations on certain phthalates. Regardless of how

this debate is resolved in the future, there is currently increasing public concern about

the safety of plastics and the plasticizers that are used to improve their physical

properties.

[0010] The desire to use disposable packaging materials that are biodegradable

and compostable has been steadily increasing in the last decade. As recently as

March, 2003, Taiwan outlawed the use of polystyrene foam in disposable packaging.

China's major cities (e.g., Beijing and Shanghai) have also outlawed the use of

polystyrene foam in disposable packaging. Commenting on solid waste policy in the

United States, the web site of American Society of Civil Engineers says that "the

problem of over consumption should be addressed, with the goal of reducing the

production and consumption of unnecessary goods, packaging and throwaways.

Toxic materials used in products and packaging and produced as byproducts in

production processes should be minimized."

[0011] Unlike plastics, paper and paperboard are made from wood pulp, which

is a renewable material. The regeneration time, however, for wood fiber — the time

required to grow a tree — is substantial, and the chemical processing needed to

produce white ("bleached") fibers has been recognized to be detrimental to the

environment. The use of unbleached and recycled fibers helps alleviate these

environmentally detrimental activities, but the use of slow-growing trees as a fiber

source when many agricultural byproduct sources are available is in itself

questionable.

[0012] Further, in the current art, starch-based food service articles typically

contain two or three major phases: a matrix material (mainly starch) that contains

inorganic filler materials and/or fibrous materials. The mechanical properties of the

starch matrix material are critical to the performance of these articles. Baked

unmodified starch is typically quite fragile and brittle when dry, but relatively soft

and pliable when the starch contains 5% to 10% moisture. In current practice, fiber

is often added to the formulation to increase the flexural strength and fracture energy

of starch-based items, especially during the period immediately after demolding,

when the moisture content of the starch is very low. Even with the addition of

significant amounts (10% or more) of fiber, however, starch-based articles are

commonly very brittle immediately after demolding or when stored for extended

periods in dry environments (heated buildings in winter, air conditioned buildings in

summer, desert environments any time of year). Brittle failure of starch-based

articles thus continues to present problems during the manufacturing process

(especially before coatings or laminated films are applied) and when the articles are

used in dry environments.

[0013] Moreover, in the current art, inorganic mineral fillers (e.g., calcium

carbonate, silica, calcium sulfate, calcium sulfate hydrate, magnesium silicate,

micaceous minerals, clay minerals, titanium dioxide) are often included in

formulations used to produce starch-based biodegradable food service articles.

These fillers are not, however, biodegradable. Marketing claims made for products

using these materials as fillers point out that the materials are natural, renewable, and

environmentally benign. However, there are inherent environmental costs associated

with the mining (or synthesis) and processing of all inorganic filler materials.

[0014] Finally, in the current art, the most commonly used fiber in starch-

based food service articles is wood-pulp fiber (similar to the paper based articles).

As the main source material for the paper industry, it is readily available, is

consistent in quality and material properties, and has the main properties needed to

serve as structural elements in the finished food service articles. The use, however,

of slow-growing trees as a fiber source when many agricultural byproduct sources

are available is, as set forth above, in itself questionable.

[0015] Accordingly, there is a need for an improved system for producing

edible, biodegradable, and compostable disposable items that can serve the full range

of uses to which containers, plates, trays, and bowls are usually put. Consumers

clearly would benefit from the introduction of a new edible food service and

packaging material. Society at large would clearly benefit from an overall reduction

in the amount of food packaging materials in the municipal solid waste stream.

[0016] Further, there is a need to reduce the proportion of persistent, non¬

biodegradable food packaging in the municipal waste stream. Development of

packaging systems that combine edible, compostable, and biodegradable materials

for structural rigidity with minimal amounts of plastic film or plastic-coated paper for

protection from water, water vapor, oxygen, and contaminants would be beneficial.

[0017] Further, development of packaging materials made entirely from

natural, edible ingredients would reduce both environmental and human health

effects of plasticizers, to whatever extent they are eventually shown to occur. Until

the debate over the issue is resolved, edible packaging materials may serve as an

alternative to plastics for concerned consumers.

[0018] There is also a need for an improvement in the current art that will

replace mineral fillers with fully biodegradable and renewable plant-based organic

materials that serve the same role as traditional mineral fillers. Even greater benefit

is available if the filler material is currently produced as a byproduct of the

production of another agricultural material.

[0019] Finally, there is also a need for methods and formulations that

incorporate fibrous materials from annually grown non-wood plants, and particularly

from materials that are byproducts of commodities already in production.

SUMMARY OF THE INVENTION

[0020] It is an object of some embodiments of the present invention to provide

a system for producing edible, biodegradable, compostable, and disposable items that

can serve as functional packaging and/or service items for ice cream and other frozen

desert products; baked goods such as cakes, muffins, cookies, breads and

sweetbreads; fruit, meat, and vegetable pies; pizza pies; candy products; and other

products designed to be eaten by humans or animals. Such items are intended to be

safe for consumption, have an appealing appearance, taste, and texture, and if

disposed of rather than consumed, to be as readily biodegradable as other foodstuffs.

These characteristics contrast sharply with standard food service and food packaging

Materials (PE, acrylic, or wax coated paperboard, PETE, HDPE, PP, PS, PVC, vinyl,

netals foil products, etc.), which are not edible, palatable, or biodegradable.

[0021] It is another object of some embodiments of the present invention to

provide a pet food packaging material that is edible, biodegradable, and compostable.

[0022] It is another object of some embodiments of the present invention to

provide an edible, compostable, and biodegradable material as a structurally rigid

internal component in a packaging system that includes a conventional exterior

barrier material (e.g., plastic film or plastic-coated paper) for protection from water,

water vapor, oxygen, and contaminants.

[0023] It is another object of some embodiments of the present invention to

provide moldable packaging materials that have mechanical properties similar to

those of molded plastic packaging items, but which are free of phthalates and other

plasticizers used in the manufacture of conventional plastics.

[0024] It is another object of some embodiments of the present invention to

provide fully edible, biodegradable, compostable, and renewable plant-based organic

materials that serve the same role as traditional mineral fillers in starch-based food

containers.

[0025] It is another object of some embodiments of the present invention to

jrovide methods and formulations that incorporate fibrous materials from non-wood

jlants, and particularly from materials that are grown annually and/or are by-products

)f commodities already in production.

[0026] These and other aspects of some embodiments of the present invention

which may become obvious to those skilled in the art through the following

description of the invention are achieved by a formulation used in making starch-

based goods and a method for use of said formulation.

[0027] One embodiment of the present invention is a composition comprising

water; starch; natural fibrous materials; a mold release agent; flavoring agents;

coloring agents; and/or wax emulsions, proteins, or other natural polymeric

compounds to adjust the product properties for particular applications wherein,

because the material is intended to be edible, all ingredients may be food grade

materials.

DETAILED DESCRIPTION OF THE INVENTION

[0028] In order to fully understand the manner in which the above-recited

details and other advantages and objects according to the invention are obtained, a

more detailed description of the invention will be rendered by reference to specific

embodiments thereof.

[0029] One embodiment of the present invention provides packaging

riaterial that is edible and is much stronger than standard ice cream cone

iormulations, while remaining functional in oven and microwave environments.

Typical envisioned applications for the present embodiment include stronger ice

:ream cones, pie shells, muffin trays, hot dog holders, candy trays, ice cream trays,

cookie holders, and dessert trays. Products with enhanced moisture resistance can be

provided by coating the tray with an edible, moisture resistant coating. Where long

term storage of food products requires a sealed moisture and oxygen barrier,

conventional coated paper or plastic film materials can be used for barrier materials,

with a rigid edible, compostable, and biodegradable insert acting to hold and protect

the food items.

[0030] Pet food containers can also be produced according to the present

embodiment. These containers are not only edible, but (unlike many conventional

packaging materials) are safe for pets' teeth as well. This new pet edible packaging

can be flavored to act as a "treat" after the pet has finished eating the meal, or served

as part of the meal itself. Elimination of pet food packaging would provide pets with

an additional source of dietary fiber, reduce the amount of pet food packaging

material in the waste stream currently being sent to landfills, and increase the overall

efficiency of pet food delivery by eliminating waste packaging material.

[0031] A formulation according to the present invention from which edible

packaging items (containers, plates, trays, bowls, cones, and cups, as well as other

novel shapes) can be produced is provided comprising water; starch; optionally

several natural fibrous materials used in combination both as structural elements (at

several size scales) in the baked items and as inexpensive organic replacements for

norganic fillers; optionally proteins and natural polymeric compounds to reduce the

mttleness of the articles produced for use in dry environments and to prevent

breakage immediately after forming when the items are typically dry; optionally wax

emulsions to increase water-resistance of the finished items; optionally a mold

release agent to reduce adhesion between baked parts and the mold system; and

optionally food grade coloring and/or flavoring agents to increase the sensory appeal

of the items.

[0032] Starch for use in the present embodiment may include, but is not

limited to, plant sources such as tubers, roots, seeds, and or fruits of plants, and

specific plants sources may include corn, potato, tapioca, rice, or wheat or similar, or

animal sources, namely glycogen, although plant sources are most preferred.

Further, the starch is preferably provided as a combination of both pregelatinized and

uncooked starches. Preferably, pregelatinized starch has a concentration in the range

of about 0% to about 30% by weight of total starch in the formulation, and more

preferably 3% to 20%, and most preferably 5% to 15%. Food-grade starches

(pregelatinized or uncooked) that have been modified by cross-linking, stabilization,

or addition of lipophilic functional groups may be included to increase resistance of

the products to softening when exposed to aqueous foods.

[0033] Proteins and natural polymeric compounds may include, but are not

limited to preparations made from casein, soy protein isolate or concentrate, or

similar such preparations. One such preparation can be prepared in the following

three steps: 1) cooking a solution of casein or soy protein isolate in water (about 10%

by weight) as per usual manufacturer's recommendations (generally, hydrating the

protein by soaking, then gradually raising the temperature and pH of the solution to

180 ⁰ F. and pH=9 to 9.5, then holding the solution at 180 ⁰ F. for 15 minutes); 2)

cooling the preparation to room temperature; and optionally, 3) adding a preservative

and blending thoroughly. The preferred concentration of preservative in the

preparation is about 0.1% or less, depending on the shelf life required for the protein

solution, the concentration of protein required in the final product, and the limits

imposed by government regulations on the dosages of preservative compounds in

edible materials.

[0034] Other proteins may also be used in combination with the casein or soy

protein preparation or separately to improve the water-resistant properties of the

containers. For example, such proteins may include albumen, gelatin, or the like.

[0035] Several natural fibrous materials may be used in combination both as

structural elements (at several size scales) in the baked items and or as inexpensive

organic fillers. Fiber elements are used both to control the molding characteristics of

the wet batter and to enhance the structural stability of the finished food service

articles. Although there is a continuum of fiber lengths and fiber aspect ratios used

in the formulation, the fibrous portion of the formulation can be in a general sense

separated into three classes (based on fiber length) that serve different functions.

Long or very long (4 to 25 mm or longer) fibers or composite fiber elements are used

to form a meshwork that helps prevent defects from forming in the batter as it

expands in the mold. Medium-length fibers (0.5 to 5 mm) also help control the flow

characteristics of the wet batter, and serve to increase the toughness of the finished

food service articles, preventing fracture during handling and during normal use.

Short fibers (<0.5 mm) serve mainly as a means to introduce readily biodegradable

material into the formulation, i.e., filler material that is more water-resistant than the

starch-based matrix that contains them. (All types of fiber provide this functionality,

but the presence of the medium, long, and very long fibers are required for the

molding, handling and usage characteristics they provide, whereas the short fiber

elements are present primarily for the contribution to water-resistance that they

make.)

[0036] Optionally, the shorter fibers may be used in conjunction with, or

replaced by other filler materials imparting the same advantages as the shorter fibers.

For example, such filler materials may include both organic and inorganic aggregates

such as calcium carbonate, silica, calcium sulfate, calcium sulfate hydrate,

magnesium silicate, micaceous minerals, clay minerals, titanium dioxide, talc, etc.

The concentration of aggregate and/or short fibers may be in a range from about 0%

to about 25% by dry weight of the formulation, in a range from about 2.5% to about

10% by total dry weight of the formulation, in a range from about 5% to about 15%

ϊry weight of the formulation, in a range from about 5% to about 20% by total dry

veight of the formulation, or in a range from about 7% to about 17% dry weight of

he formulation.

[0037] In one aspect of the present embodiment, the organic filler material

may include ground walnut shells. Ground walnut shells results in fibrous mater

comprising short fibers. The ground walnut shells may be used alone as the filler

material or may be combined with other filler materials. When used alone the

preferred concentration is about 8% by dry weight.

[0038] Fibers from several sources are typically included in the formulation.

Relatively high quality fibers from grass or reed species provide the mid-length

fibers that contribute most to the structural stability and resilience if the finished

articles. The long to very long fibers or fiber composites may come from lightly

processed agricultural byproducts, e.g., stalk or husk materials that have been

chopped, ground, or milled to an appropriate size. Under appropriate processing

conditions {e.g., hammer milling), these materials can also provide a considerable

amount of the very short fiber that serves to replace starch and add water resistance

to the finished article. Fibrous material in the form of ground nut shells (or other

very hard, lignin-rich plant materials) may also serve as organic, relatively water

resistant, biodegradable fibers that replace conventional filler materials.

[0039] Moreover, these other sources of fiber suitable as structural elements in

starch-based food service articles are readily available. Some of these are from fast-

growing plants that can be broadly characterized as grasses or reeds, such as kenaf

and bamboo, which provide fiber with smaller associated environmental costs than

taking fiber from trees. A growing segment of the fiber industry is based on the use

of fiber from these plants. In many cases the quality and consistency of fibers taken

from these plants (after processing) is as good as that provided by the wood pulp

industry. In addition, fiber is also widely available as a by-product of agricultural

production. Stalks, stems, and husks from cereal grains, for example, are a ready

source of fibrous material that, while not as high in quality as the fiber taken from

wood or the better grass species, is extremely cheap and, as a by-product, has

essentially no additional environmental cost (beyond whatever environmental costs

are associated with the production of the main crop).

[0040] The fibrous materials included in the formulations described here vary

greatly in both fiber length and fiber aspect ratio. Overall, however, it is preferred

that the materials have an average fiber length that is less than about 2 mm and an

average aspect ratio that is in the range of about 5:1 to 25:1.

[0041] The preferred wax emulsions in the formulation, used to increase

water-resistance, is a stable aqueous emulsion usually made of carnauba, candelilla,

rice bran, paraffin, or any other food-grade wax: vegetable waxes are preferred over

animal and mineral waxes, and natural waxes are preferred over synthetic varieties.

The wax type is selected based on the particular application and desired properties of

the final product. The emulsion is usually prepared by means of emulsifying agents

and mechanical agitation. Examples of wax emulsions suitable for use in the present

formulation include emulsified carnauba wax and emulsified candelilla wax.

Emulsifiers include all of those permitted for food applications, including (but not

limited to) sorbitan monostearate, Polysorbate 60, Polysorbate 65, Polysorbate 80,

food-grade gums (e.g., arabinogalactan, carrageenan, furcelleran, xanthan), stearyl

monoglyceridyl citrate, succistearin, hydroxylated lecithin, and many other

compounds.

[0042] A mold release agent, or abherent, is provided to reduce adhesion

between baked parts and the mold system. Examples of specific mold release agents

that are suitable for use in the present formulation include, but are not limited to

metal stearate compounds (e.g., aluminum, magnesium, calcium, potassium, sodium,

or zinc stearates), fatty acids (e.g., oleic acid, linoleic acid, etc.) fats, oils, or similar

materials, or a combination of any of the foregoing.

[0043] The coloring agents preferred for use in the present formulation are

water insoluble pigment types considered safe for use in food products (e.g., iron

oxides, ultramarines, chromium-cobalt-aluminum oxides, ferric ammonium

ferrocyanide, ferric ferrocyanide, manganese violet, carbazole violet). Alternatively,

aluminum lake colorants, water-soluble food dyes, and combinations of pigments, or

combinations of pigments with lakes and/or dyes may be used for some applications.

[0044] Containers fashioned from a mix formulation according to the present

invention can be of varying shape and thickness depending upon the desired use for,

md properties of, the final container. For example, the containers may be fashioned

nto open containers such as trays, cones, pie plates, cups, or bowls, or any other

iseful configuration known in the art.

[0045] Further, the thickness of any portion of the container will preferably

vary in the range from about 0.5 mm to about 3.2 mm, and more preferably from

about 1.5 mm to about 3.0 mm, and most preferably from about 1.6 mm to about 2.5

mm. The thickness of the containers may also vary across the cross-section of the

container.

[0046] In another embodiment of the present invention a biodegradable

material such as an edible coating and or sealant may be applied to containers

fashioned from the mix formulation. Said biodegradable material may be applied

such that it permeates the inner and/or outer surfaces of the container, thereby

improving water and heat resistant properties of the container. Said materials when

applied as a coating, may partially or completely permeate the container matrix or a

combination of a forming a coating and partially or completely permeating the

container matrix.

[0047] A further embodiment of the invention is a method to produce a

container or other article for use with food or beverage containers. Said method

comprises providing the mix formulation set forth above; heating said mix in a mold

of desired shape to form a container of a corresponding desired shape. Said method

may further comprise steps set forth in U.S. Patent Application Ser. No. 10/608,441,

filed Jun. 27, 2003, which, by reference, is incorporated herein in its entirety.

[0048] A further method according to the present invention comprises the

steps of providing a mold apparatus having a cavity in the shape of a desired final

product and a gap or gaps for venting vapor from the mold apparatus produced

during heating or baking, heating or baking the mold apparatus, adding a mixture that

is liquid or semi-liquid to the cavity of the mold apparatus prior to closing the mold

apparatus and closing the mold apparatus, wherein as vapor or steam is produced in

the cavity during heating or baking, the mixture is pushed by vapor or steam pressure

to completely fill the cavity, and upon sufficient contact of the mixture to the heated

mold apparatus a skin forms on the outer surface of the mixture, the skin being

permeable or semi-permeable to the vapor or steam and the skin and gap being such

that, in combination, they allow escape of steam or vapor from the cavity to the

exterior of the mold apparatus but do not allow any significant amount of the mixture

to escape. "Any significant amount of mixture" as referred to herein is any amount

the loss of which would cause any one of the drawbacks found in the prior art in a

meaningful amount, such as waste of raw materials, waste of energy needed to heat

additional mixture, additional processes to remove excess material to form the final

product and clogging of the gap or gaps.

[0049] The vapor escapes while the mixture is retained in the cavity because

the gap is of sufficiently small size that the skin formed on the surface of the mixture

from contact of the mixture with the heated mold surface, when under sufficient

pressure from the steam or vapor produced during heating or baking of the mixture,

allows the steam or vapor to escape through the skin and then through the gap to the

exterior of the mold apparatus without rupture of the skin. Because the skin is not

permeable to the mixture, which may still be liquid or semi-liquid prior to the

completion of heating or baking, the mixture cannot escape from the cavity of the

mold apparatus.

[0050] The aforementioned method according to the present invention allows

for venting of the vapors produced during baking without significant loss of mixture

and the associated drawbacks of said loss outlined above such as waste of raw

materials, waste of energy needed to heat additional mixture, additional processes to

remove excess material to form the final product and clogging of the gap or gaps.

[0051] The aforementioned method according to the present invention may be

used to manufacture both edible baked goods and other baked products such as

starch-based materials for use as food containers and the like. Mixtures for use in

said method are typically water-based and include mixtures as described herein. One

skilled in the art, however, will recognize that the mixtures need not be water-based,

such as alcohol-based mixtures or other non-water-based mixtures. Specific

examples of mixtures that may be used said method should be readily apparent to one

skilled in the art and include, but are not limited to, common baking mixtures such as

waffle, cookie dough, or ice cream cone batter, starch-based mixtures comprised of

starch and water and mixtures comprising composite materials mixed with resins that

form skins which are still permeable to the gases produced during heating or baking.

Further, specific baking procedures such as heating temperature and time will vary

depending upon the specific mixture to be heated or baked and should be apparent to

one skilled in the art.

[0052] Although the invention has been described with respect to specific

embodiments and examples, it will be readily appreciated by those skilled in the art

that modifications and adaptations of the invention are possible without deviation

from the spirit and scope of the invention. Accordingly, the scope of the present

invention is limited only by the following claims.