Classifications

• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L29/00—Foods or foodstuffs containing additives; Preparation or treatment thereof
  • A23L29/20—Foods or foodstuffs containing additives; Preparation or treatment thereof containing gelling or thickening agents
  • A23L29/269—Foods or foodstuffs containing additives; Preparation or treatment thereof containing gelling or thickening agents of microbial origin, e.g. xanthan or dextran
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
  • B65D65/38—Packaging materials of special type or form
  • B65D65/46—Applications of disintegrable, dissolvable or edible materials
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23G—COCOA; COCOA PRODUCTS, e.g. CHOCOLATE; SUBSTITUTES FOR COCOA OR COCOA PRODUCTS; CONFECTIONERY; CHEWING GUM; ICE-CREAM; PREPARATION THEREOF
  • A23G3/00—Sweetmeats; Confectionery; Marzipan; Coated or filled products
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23G—COCOA; COCOA PRODUCTS, e.g. CHOCOLATE; SUBSTITUTES FOR COCOA OR COCOA PRODUCTS; CONFECTIONERY; CHEWING GUM; ICE-CREAM; PREPARATION THEREOF
  • A23G3/00—Sweetmeats; Confectionery; Marzipan; Coated or filled products
  • A23G3/34—Sweetmeats, confectionery or marzipan; Processes for the preparation thereof
  • A23G3/50—Sweetmeats, confectionery or marzipan; Processes for the preparation thereof characterised by shape, structure or physical form, e.g. products with supported structure
  • A23G3/54—Composite products, e.g. layered, coated, filled
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L29/00—Foods or foodstuffs containing additives; Preparation or treatment thereof
  • A23L29/20—Foods or foodstuffs containing additives; Preparation or treatment thereof containing gelling or thickening agents
  • A23L29/206—Foods or foodstuffs containing additives; Preparation or treatment thereof containing gelling or thickening agents of vegetable origin
  • A23L29/212—Starch; Modified starch; Starch derivatives, e.g. esters or ethers
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23L—FOODS, FOODSTUFFS, OR NON-ALCOHOLIC BEVERAGES, NOT COVERED BY SUBCLASSES A21D OR A23B-A23J; THEIR PREPARATION OR TREATMENT, e.g. COOKING, MODIFICATION OF NUTRITIVE QUALITIES, PHYSICAL TREATMENT; PRESERVATION OF FOODS OR FOODSTUFFS, IN GENERAL
  • A23L29/00—Foods or foodstuffs containing additives; Preparation or treatment thereof
  • A23L29/20—Foods or foodstuffs containing additives; Preparation or treatment thereof containing gelling or thickening agents
  • A23L29/269—Foods or foodstuffs containing additives; Preparation or treatment thereof containing gelling or thickening agents of microbial origin, e.g. xanthan or dextran
  • A23L29/274—Pullulan
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23P—SHAPING OR WORKING OF FOODSTUFFS, NOT FULLY COVERED BY A SINGLE OTHER SUBCLASS
  • A23P20/00—Coating of foodstuffs; Coatings therefor; Making laminated, multi-layered, stuffed or hollow foodstuffs
  • A23P20/10—Coating with edible coatings, e.g. with oils or fats
  • A23P20/105—Coating with compositions containing vegetable or microbial fermentation gums, e.g. cellulose or derivatives; Coating with edible polymers, e.g. polyvinyalcohol
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23P—SHAPING OR WORKING OF FOODSTUFFS, NOT FULLY COVERED BY A SINGLE OTHER SUBCLASS
  • A23P20/00—Coating of foodstuffs; Coatings therefor; Making laminated, multi-layered, stuffed or hollow foodstuffs
  • A23P20/10—Coating with edible coatings, e.g. with oils or fats
  • A23P20/15—Apparatus or processes for coating with liquid or semi-liquid products
  • A23P20/18—Apparatus or processes for coating with liquid or semi-liquid products by spray-coating, fluidised-bed coating or coating by casting
• • A—HUMAN NECESSITIES
  • A23—FOODS OR FOODSTUFFS; TREATMENT THEREOF, NOT COVERED BY OTHER CLASSES
  • A23V—INDEXING SCHEME RELATING TO FOODS, FOODSTUFFS OR NON-ALCOHOLIC BEVERAGES AND LACTIC OR PROPIONIC ACID BACTERIA USED IN FOODSTUFFS OR FOOD PREPARATION
  • A23V2002/00—Food compositions, function of food ingredients or processes for food or foodstuffs

Definitions

• PVOH polyvinyl alcohol
• Some types of packaging material can be dissolved in water.
• water soluble pouches made from polyvinyl alcohol (PVOH) film have been used to package pre- weighed farm chemicals and concrete additives. These PVOH pouches can be added to tanks or mixers, where the packaging material dissolves and the contents are released. PVOH pouches have also been used with pre-weighed laundry soap and dishwashing detergent.
• PVOH is not a food ingredient, so the PVOH technology has thus far been limited to non-food applications.
• Edible films have been made from other film-forming polymers such as pullulan.
• edible strips containing pullulan and a breath-freshening agent have been sold for human consumption.
• Cough medicines, vitamins, and dietary supplements have also been supplied in the form of edible strips.
• Pullulan has a number of properties that make it suitable for use in edible compositions.
• one problem with pullulan films is their limited ability to elongate without breaking. This problem limits the ability of pullulan films to envelop other materials, as opposed to having other materials interspersed in the film itself.
• a survey of tensile strength and elongation properties of packaging films indicates that strength above 1,000 gram force and elongation of greater than 50% is likely to give pullulan-based films suitable for commercial packaging.
• One aspect of the invention is an edible article that comprises a food product and a water-soluble film that encloses the food product.
• the film consists essentially of a major amount of pullulan on a dry solids basis, and a minor amount of more than one member selected from the group consisting of glycerol, propylene glycol, sorbitol, and polyethylene glycol.
• Consists essentially of in this context means that the composition is essentially free of polysaccharides other than those listed.
• the film comprises about 35-80% by weight pullulan on a dry solids basis.
• the film comprises a plasticizer mixture included at up to about 40% by weight.
• the plasticizer mixture in some embodiments uses a combination of glycerol, propylene glycol, and sorbitol.
• the film optionally can further comprise citric acid, starch or a starch derivative (such as dextrin or maltodextrin), alginate, xanthan gum, modified cellulose, polydextrose, or a combination of two or more thereof.
• the water-soluble film that encloses the food product comprises a major amount of pullulan on a dry solids basis, gelatin, and at least two of glycerol, propylene glycol, sorbitol, and polyethylene glycol.
• the film can also comprise at least one salt, such as NaCl.
• the film can optionally also comprise at least one internal film release agent.
• Another aspect of the invention is a water-soluble, edible film, comprising the above- described components.
• Yet another aspect of the invention is a method for making the water-soluble, edible film.
• the method comprises (a) preparing a film-forming composition as described in various embodiments above, (b) coating a substrate with a solution or suspension comprising at least one surfactant, and (c) casting the film-forming composition on the substrate.
• Another aspect of the invention is a method for making an edible article.
• the method comprises preparing a film-forming composition as described in various embodiments above; forming the film-forming composition into a water-soluble film; and enclosing a food product with the film.
• the components of the film- forming composition can be as described above.
• the film can be stretched longitudinally by at least about 50%, or at least about 100%, without breaking.
• the food product can be enclosed by placing the food product between two pieces of film and heat- sealing the two pieces of film to form a sealed enclosure around the food product.
• the food product can be enclosed by placing the food product between two pieces of film and applying moisture and pressure to at least portions of the film to form a sealed enclosure around the food product.
• One specific method of enclosing that can be used is vacuum-forming the film around the food product.
• Another aspect of the invention is an edible film that comprises a first layer comprising a major amount of at least one food grade wax; a second layer comprising a major amount of pullulan and further comprising at least one plasticizer; and a third layer comprising at least one surfactant that is substantially immiscible with aqueous pullulan compositions but which adheres to pullulan surfaces.
• the at least one surfactant is at least partially crystalline.
• the at least one surfactant comprises sodium stearoyl lactylate.
• the second layer further comprises particles of food grade wax.
• Another aspect of the invention is an edible article that comprises a food product and edible film that encloses the food product.
• the film comprises first, second, and third layers, as described in the previous paragraph.
• the first layer which comprises a major amount of at least one food grade wax, is in contact with the food product.
• Another aspect of the invention is a method for making an edible film.
• the method comprises applying to a substrate a solution or suspension that comprises a major amount of at least one surfactant that is substantially immiscible with aqueous pullulan compositions; drying or concentrating the solution or suspension to form a first layer that comprises a major amount of dried surfactant that is at least partially crystalline; applying to the dried surfactant layer an aqueous solution or suspension that comprises pullulan, at least one plasticizer, and at least one food grade wax; and drying or concentrating the aqueous solution or suspension, whereby a second layer and a third layer are formed.
• the second layer is on top of the first layer and the third layer is on top of the second layer.
• the second layer comprises plasticizer and a major amount of pullulan and the third layer comprises a major amount of food grade wax.
• Yet another aspect of the invention is an edible film that comprises a major amount of pullulan on a dry solids basis; at least one salt; and at least one plasticizer.
• the film comprises at least two salts, such as NaCl and MgCl 2 , for example.
• Another aspect of the invention is an edible article that comprises a food product and edible film that encloses the food product, wherein the film is as described in the previous paragraph.
• Another aspect of the invention is a film structure that comprises an edible film adhered to a peelable, flexible substrate.
• the edible film comprises a major amount of pullulan on a dry solids basis; and at least one plasticizer.
• the flexible substrate comprises a polymeric film, such as a polyester film, for example.
• Figure 1 is a schematic drawing of a multi-layer film in accordance with one embodiment of the invention.
• Figure 2 is a schematic drawing of a film on a peelable, flexible substrate in accordance with one embodiment of the invention.
• Figure 3 is a schematic drawing of a pouch that contains a food product and is made from a film in accordance with one embodiment of the invention.
• One embodiment of the present invention relates to edible articles which contain a food product and can be consumed orally or dissolved (entirely or partially) in water. These articles have an outer layer or surface made from a film-forming composition, and the food product is enclosed inside the outer layer.
• the film-forming composition comprises a major amount of pullulan on a dry solids basis.
• a major amount in this context means that the composition contains more pullulan on a dry solids basis than any other component.
• the film-forming composition comprises about 35-80% by weight pullulan on a dry solids basis.
• other film-forming materials can be included in the film-forming composition as well, such as alginates, xanthan gum, modified cellulose, polydextrose, starch or a starch derivative (such as dextrin or maltodextrin), and combinations of two or more such materials. Inclusion of one or more of these polymers can enhance film strength and reduce cost as compared to pullulan-only compositions.
• the film-forming composition also includes a minor amount of plasticizer, in particular at least two of the plasticizers glycerol, propylene glycol, sorbitol, and polyethylene glycol.
• a minor amount in this context means that the composition contains less total plasticizer than it does pullulan on a dry solids basis.
• One commercially available polyethylene glycol that is suitable for use in the invention is polyethylene glycol molecular weight 200 (PEG 200).
• the film-forming composition comprises the plasticizers glycerol, propylene glycol, and sorbitol.
• the film-forming composition can comprise about 1-30% glycerol, about 1-30% propylene glycol, and about 1-30% by weight sorbitol on a dry solids basis. Each of these materials is commercially available.
• the composition can also include other plasticizers.
• the film-forming composition comprises a plasticizer mixture at up to about 40% by weight.
• the film exhibits high tensile strength, but can only be stretched and elongated about 10% in length before it breaks.
• pullulan-containing films that also contain plasticizers exhibit increased strength and elongation compared to pullulan films that do not contain plasticizers, up to a point.
• increasing the plasticizer content of a pullulan film beyond this level often leads to greatly decreased tensile strength.
• addition of individual food grade plasticizers to a pullulan polymer solution prior to casting and drying gave films with elongations above 10%, but at the expense of greatly reduced tensile strength.
• pullulan compositions that include at least two of the plasticizers glycerol, propylene glycol, sorbitol, and polyethylene glycol can be used to produce pullulan films that have high elongation and high tensile strength, even at relatively high plasticizer concentrations.
• the film can be elongated at least about 50%, and in some cases at least about 100%, without breaking.
• the elongation without breaking is at least about 200%, or at least about 300%.
• these enhancements to the elongation properties of the film are achieved without a substantial reduction in tensile strength.
• the composition optionally can also contain one or more additives that are suitable for use in foods, such as fillers, surfactants, stabilizers, organic acids (such as citric acid), and flavorings.
• One specific embodiment of the invention is a water-soluble, edible film-forming composition that consists essentially of a major amount of pullulan on a dry solids basis, and a minor amount of more than one member selected from glycerol, propylene glycol, sorbitol, and polyethylene glycol.
• This composition can be formed into films having a thickness of less than 2.2 mils (0.0022 inches or 0.056 mm) that will exhibit tensile strength in excess of 1,000 grams force and elongation to break in excess of 50%.
• the water-soluble, edible film- forming composition consists essentially of a major amount of pullulan on a dry solids basis and minor amounts of (i) a co-polysaccharide selected from the group consisting of alginates, cellulose ethers, modified starches, and combinations thereof, and (ii) more than one member selected from the group consisting of glycerol, propylene glycol, sorbitol, and polyethylene glycol.
• composition contains less total plasticizer than it does pullulan on a dry solids basis, and also contains less total co- polysaccharide than it does pullulan on a dry solids basis.
• the composition can be formed into a film having a thickness of less than 2.2 mils that will exhibit tensile strength in excess of 1 ,000 grams force and elongation to break in excess of 50%.
• the film-forming composition that can be used to form a water-soluble, edible film, comprises a major amount of pullulan on a dry solids basis, and also comprises lesser amounts of gelatin and at least two of glycerol, propylene glycol, sorbitol, and polyethylene glycol.
• gelatin as a secondary polymer can maintain or improve elongation while maintaining film strength.
• Gelatin also gives the film a smooth surface without increased tackiness and blocking.
• the film-forming composition comprises about 35-80% by weight pullulan and about 0.5-22.5% by weight gelatin on a dry solids basis.
• the composition can comprise the plasticizers glycerol, propylene glycol, and sorbitol.
• the film-forming composition can comprise about 1-30% glycerol, about 1-30% propylene glycol, and about 1-30% by weight sorbitol on a dry solids basis.
• the composition can also comprise at least one salt. It has been found that the addition of salt to the films improves film elongation. Typically, in order to improve elongation, surface properties are sacrificed such as blocking and tackiness. However, when salt is included in the composition to increase elongation, surface properties in many instances are improved. Films that contain salt and a suitable level of traditional plasticizer, do not block and are not tacky, and therefore can be rolled onto themselves more easily. Examples of suitable salts include NaCl and KCl. In certain embodiments of the invention, the concentration of salt in the film-forming composition is about 0.3-15% by weight on a dry solids basis.
• Films with a salt content of ⁇ 10% or greater are cloudy with a powder finish as some of the salt precipitates out of the film to the surface on drying. Films with lower salt content of -5% or less still have good elongation and surface properties without any residual salt precipitating from the films.
• the film-forming composition can comprise at least one internal film release agent, to make it easier to peel the film from the substrate surface on which it is cast.
• suitable examples of internal film release agents include, but are not limited to, polyoxyethylene sorbitan monooleate, sodium lauryl sulfate, and combinations thereof.
• Polyoxyethylene (20) sorbitan monooleate is commercially available as Polysorbate 80.
• an aqueous pullulan solution can be cast onto a flat surface, and then heated and dried to form the film.
• Methods for controlling the thickness of the film are also well known.
• the water-soluble, edible film is formed by a method comprising preparing a film-forming composition as described above, coating a substrate (e.g., a stainless steel surface) with a solution or suspension that comprises at least one surfactant, and casting the film-forming composition on the substrate. After suitable heating and/or drying, the film can be peeled from the substrate.
• Film gels that are cast directly onto a stainless steel substrate often do not release well from the steel, especially films that have 75-125% elongation to break. These types of films will often simply stretch out and become distorted when one attempts to remove them from untreated steel.
• the steel substrate can be treated with solutions or suspensions that comprise release agents. The coating of the substrate with the solution or suspension of a food grade surfactant
• Suitable surfactants for this purpose include, but are not limited to, propylene glycol monostearate, sodium stearoyl lactylate, polyoxyethylene sorbitan monooleate (e.g., Polysorbate 80), sodium lauryl sulfate, salts of stearic acid, or a combination thereof.
• Suitable surfactants can be used in quantities up to 10% by weight in solutions of water and/or alcohol (e.g., isopropyl alcohol), or other suitable solvent systems.
• alcohol e.g., isopropyl alcohol
• a film can be formed into a pouch, the food product can be placed in the pouch, and then the opening in the pouch can be sealed, for example by application of heat and/or moisture.
• One specific technique that can be used is vacuum- forming the film around the food product. Vacuum forming has the advantage of requiring less extreme folding and bending of the film web under tension, as compared to some other methods of enclosing a product with a film.
• the food grade films of the present invention can have the tensile strength and elongation properties necessary to successfully produce edible packages on commercial vacuum-forming equipment. They also can have the ability to form many different shapes and work on complex molds more successfully than at least some other commercial film- forming materials. In some embodiments, the films exhibit tensile strength in excess of 1,000 grams force and elongation to break in excess of 50%. In some embodiments, the films have elongation to break of 75-125%.
• a wide variety of food products can be enclosed, including ones that need to be dissolved or dispersed in water for cooking and ones that are supplied in single-serve packages for human consumption.
• Examples of such food products include, but are not limited to powdered beverage mixes (such as cocoa drink products, soft drink products, and cider drink products), powdered cheese products, powdered egg products, candy, dry soup and casserole mixes, food dyes and spices.
• powdered beverage mixes such as cocoa drink products, soft drink products, and cider drink products
• powdered cheese products such as cocoa drink products, soft drink products, and cider drink products
• powdered egg products powdered egg products
• candy dry soup and casserole mixes
• food dyes and spices examples include, but are not limited to powdered beverage mixes (such as cocoa drink products, soft drink products, and cider drink products), powdered cheese products, powdered egg products, candy, dry soup and casserole mixes, food dyes and spices.
• the food product itself can be, but does not necessarily have to be, water-soluble.
• the film can be utilized in the packaging of a dry food ingredient or an oil based liquid food ingredient.
• the films can be used in the packaging of any foodstuff that requires addition to water or water-containing food products. This could include, for example, drink mixes, vitamin and mineral additives, colors, flavors, and any other ingredients that could be added to food during batch preparation at a food production plant, or even during food preparation by an individual prior to consumption.
• the edible films of the present invention have increased elongation without being tacky.
• the use of such films in the packaging of food products can reduce waste, as the entire package can be consumed, leaving nothing to throw away.
• the precise amount of ingredient added would be known. There would be no loss of the ingredient by sticking to the inside of the package, since the entire package would be cooked into the product.
• a multilayer edible film comprises a first layer that comprises a major amount of at least one food grade wax; a second layer that comprises a major amount of pullulan and further comprises at least one plasticizer; and a third layer.
• the third layer comprises at least one surfactant that is substantially immiscible with aqueous pullulan compositions but which adheres to pullulan surfaces.
• the at least one surfactant is at least partially crystalline in form.
• the surfactant can be, for example, sodium stearoyl lactylate.
• the concentration of the at least one surfactant in the overall film is about 0.001-0.1 % by weight, or in some cases about 0.001-0.05 %.
• the second layer can optionally also comprise particles of food grade wax.
• the second layer can comprise about 35-80% by weight pullulan on a dry solids basis
• the plasticizer in the second layer can comprise at least two of glycerol, propylene glycol, sorbitol, and polyethylene glycol.
• the second layer comprises glycerol, propylene glycol, and sorbitol, for example, about 1-30% glycerol, about 1-30% propylene glycol, and about 1-30% by weight sorbitol on a dry solids basis.
• the second layer can comprise, in addition to the pullulan, a secondary film-forming material, such as about 0.5-22.5% by weight gelatin on a dry solids basis, starch, a starch derivative, alginate, xanthan gum, collagen, polydextrose, or a combination of two or more thereof.
• the second layer can also comprise at least one salt, such as NaCl, MgCl 2 , or a combination thereof, for example. If salt is present, it preferably is present in the second layer at a concentration of about 0.3-15% by weight on a dry solids basis.
• Another embodiment of the invention is an edible article, comprising a food product and edible film that encloses the food product, wherein the film comprises first, second, and third layers, as described above.
• the first layer is in contact with the food product.
• Another embodiment of the invention is a method for making an edible film.
• the method comprises: applying to a substrate a solution or suspension that comprises a major amount of at least one surfactant that is substantially immiscible with aqueous pullulan compositions; drying or concentrating the solution or suspension to form a first layer that comprises a major amount of dried surfactant that is at least partially crystalline; applying to the dried surfactant layer an aqueous solution or suspension that comprises pullulan, at least one plasticizer, and at least one food grade wax; and drying or concentrating the aqueous solution or suspension, whereby a second layer and a third layer are formed.
• the second layer is on top of the first layer and the third layer is on top of the second layer.
• the second layer comprises plasticizer and a major amount of pullulan and the third layer comprises a major amount of food grade wax.
• This three layered structure can be formed in a single pass through a continuous film casting process.
• the procedure first calls for application of a surfactant such as sodium stearoyl lactylate (SSL, 2% in isopropanol) to a stainless steel casting surface as a release agent.
• SSL sodium stearoyl lactylate
• the solvent rapidly evaporates to give a dried release layer of SSL prior to casting.
• an aqueous pullulan casting solution containing a food grade wax emulsion as one of the formulation components, is deposited as a thin, uniform film on the casting surface.
• the film is then subjected to controlled drying conditions and is dried to moisture of less than 15% by weight over a few minutes.
• the wax particles tend to migrate toward the open surface of the film due to their relatively low surface energy.
• a layer of partially crystalline SSL is found on the film surface that was in contact with the stainless steel casting substrate.
• a layer of wax particles is found on the surface of the film that was open to the air during the drying process. In between these two surface layers is the middle layer containing predominantly pullulan and the other water soluble ingredients in the casting formulation.
• FIG. 1 shows in schematic form one embodiment of this three layered film.
• the central layer in the film is the matrix 16 which comprises pullulan.
• Within the pullulan matrix 16 are a plurality of wax particles 14, and there is a thin wax layer 18 on the film surface.
• the pullulan film formulation can contain up to about 10% wax by weight, but a wax content of less than about 5% is usually preferred. Suitable waxes include paraffin wax and other food-grade waxes such as carnauba, candelilla, or beeswax.
• the surfactant SSL can be replaced by any surfactant that is immiscible with the aqueous casting gel, but exhibits good adhesion to pullulan film surfaces.
• the surface (e.g., SSL) layer not only provides improved release of the dried film from the stainless steel casting belt, but also gives a slight hydrophobic character to the side of the film that will be used on the outside of the edible package. This slight hydrophobicity decreases the sensitivity of the film to changes in environmental humidity. The pouch does not become so hydrophobic as to be insoluble in water.
• the wax layer can be used for the side of the film in contact with the food grade fill material that will be contained in the edible pouch.
• the wax layer decreases the moisture migration between the fill material and the film layer of the pouch itself.
• the wax layer also provides significant anti-blocking properties to the film. Another added benefit to this wax layer is that it provides enhanced slip of the film in contact with the packaging machine during high speed conversion operations.
• the middle layer of predominantly pullulan can provide the required strength and flexibility of the three layered film structure.
• various embodiments of this three layered film can provide improved functional properties such as increased resistance to environmental humidity, increased resistance to moisture migration from food-grade fill materials into the packaging film, and improved slip to more easily slide through high speed packaging equipment.
• These enhancements can provide improved shelf life for packaged food products and can extend the range of equipment that can be used to convert the films into edible packaging.
• Another embodiment of the invention is an edible film that comprises a major amount of pullulan on a dry solids basis, at least one salt, and at least one plasticizer.
• the film comprises at least two salts, such as combinations of NaCl and MgCl 2 , for example.
• the at least one salt is present in the film at a concentration of about 0.3-15% by weight on a dry solids basis.
• the plasticizers and other components of the film can be as described above with respect to other embodiments of the invention.
• the film of this embodiment can be used to prepare an edible article that comprises a food product that is enclosed by the edible film.
• Another embodiment of the invention is a film structure that comprises an edible film adhered to a peelable, flexible substrate.
• the edible film comprises a major amount of pullulan on a dry solids basis, and at least one plasticizer.
• the flexible substrate comprises a polymeric film, such as a polyester film, for example.
• the flexible substrate can be a biodegradable polymer film, such as one that comprises polylactic acid, polyglycolic acid, copolymers of lactic and glycolic acid, or mixtures of two or more such polymers.
• the plasticizers and other components can be as described above with respect to other embodiments of the invention.
• the film of this embodiment can be used to prepare an edible article that comprises a food product that is enclosed by the edible film.
• Figure 2 shows one embodiment of this film structure.
• a pullulan film 20 as described above is releasably adhered to a polyester film 22, from which it can be removed at the desired time.
• This bilayered film structure can be especially useful in a high speed packaging operation.
• a potential problem associated with using edible film on conventional packaging equipment is that all film surfaces must be kept clean because the packaging film is part of the edible product. This is different from the conventional packaging strategy where one surface of the packaging film comes in contact with the food and the other surface is exposed and protects the food product from the environment.
• the outer surface of the edible film is protected by a polyester layer during packaging and can be easily removed prior to using the food product contained in the edible package.
• Any of the films described herein can be used to package a food product, for example by forming a pouch as shown in cross-section in Figure 3, where the film 30 encloses an inner contained area 32 into which is placed a food product 34. Edges 36 of the film can be sealed to form an enclosed package.
• Polymer solutions were prepared to have less than 10,000 centipoises viscosity. Water was placed in a vessel and agitated, and then the dry polymer powder was added to the vortex of the stirring liquid over time. Stirring at 100-1000 rpm was continued for 30-60 minutes, then the solution was allowed to rest for at least two hours prior to use.
• Polymer solutions were blended as needed to give the desired ratios and concentrations, and then the oligomers, plasticizers, and other additives were added neat to the polymer solutions with mixing over time.
• Aqueous solutions were cast onto Mylar film by machine or by hand using drawdown bars with a gap of either 20 or 40 mils at a rate of about 1 meter per second.
• the Mylar film was taped onto 0.50 in thick glass sheets prior to solution casting. The whole assembly
• Film Conditioning and Testing Films were conditioned in a controlled environment room set for 70 0 F and 50% RH for 1 to 5 days (average 3) prior to testing. Samples were transferred to the testing area in Zip-Loc® bags. Samples were tested and evaluated for tensile strength (gram force) and % elongation using a small laboratory Instron physical testing unit. In the test, a metal probe with an elliptical tip is forced thru the plane of a tightly held piece of film. The amount of force required to break the film, and the distance the probe travels to break the film are used to calculate the material properties. Pouch Production via Vacuum Forming
• a die was selected and placed on the table under a vertically-movable frame.
• a sheet of film (7 in x 11 in) was placed on the bottom part of the frame.
• the upper part of the frame was lowered and locked onto the bottom part.
• a vacuum was pulled through the die, the film was lowered onto the die and sucked into it, forming a pouch, and then the pouch was filled with selected material.
• a second piece of film was laid smoothly on top of the pouch.
• a hot iron 200- 300 0 F was manually pressed onto both pieces of film at the edge of the filled area. The iron was held in place for 2-5 seconds.
• a second piece of film was wrapped around a block and was quickly pressed into a damp paper towel.
• the lightly moisturized film was pressed onto the previously formed pouch for about 2-5 seconds.
• PI-20 Commercially available pullulan from Hayashibara (PI-20) was used to prepare films with one or more of the following additives: glycerol, propylene glycol (PPG), Sorbitol
• the films made with STAR-DRI 5 maltodextrin and sodium alginate (and optionally Nu-CoI 2004) with pullulan as the predominant polymer showed high tensile strength. High elongations were seen in films containing glycerol, propylene glycol and sorbitol (and optionally citric acid) with pullulan as the predominant polymer. Variations in thickness resulted in films with tensile strength in excess of 1,000 grams force and elongation to break in excess of 50%.
• Die 1 Half egg-shaped: 2.50 in L by 1.88 in W by 0.69 in D - maximum depth tapered down from edge. Die 2) Rectangular: 4.50 in L by 2.75 in W by 0.50 in D — uniform depth straight down from edge.
• Example 3-1 Film #6 was successfully vacuum formed using Die #1 and about 12 grams of finely powdered ALLEGGRA® FS74 egg product was filled in the pouch. Film #1 was successfully used to close the package by heat sealing.
• Example 3-2 - Film #5 was successfully vacuum formed using Die #1 and about 20 grams of finely powdered Swiss Miss® Hot Cocoa Mix was filled in the pouch. Film #1 was unsuccessfully used to close the package due to fracture during heat sealing.
• Example 3-3 Film #5 was successfully vacuum formed using Die #1 and about 12 grams of finely powdered ALLEGGRA® FS74 egg product was filled in the pouch. Film #5 was successfully used to close the package by heat sealing.
• Example 3-4 - Film #3 was successfully vacuum formed using Die #1 and about 20 grams of finely powdered Swiss Miss® Hot Cocoa Mix was filled in the pouch. Film #3 was successfully used to close the package by heat sealing.
• Example 3-5 Film #4 was successfully vacuum formed using Die #1 and about 12 grams of finely powdered ALLEGGRA® FS74 egg product was filled in the pouch. Film #4 was successfully used to close the package by heat sealing.
• Example 3-6 Film #4 was successfully vacuum formed using Die #2 and about 28 grams of finely powdered Swiss Miss® Hot Cocoa Mix was filled in the pouch. Film #4 was successfully used to close the package by heat sealing. This package was later found to have a minute hole in the deep corner of a vacuum formed region.
• Example 3-7 Film #3 was successfully vacuum formed using Die #2 and about 40 grams of finely powdered Swiss Miss® Hot Cocoa Mix was filled in the pouch. Film #3 was successfully used to close the package by heat sealing.
• Example 3-8 Film #4 was successfully vacuum formed using Die #2 and about 28 grams of finely powdered Swiss Miss® Hot Cocoa Mix was filled in the pouch. Film #4 was successfully used to close the package by heat sealing. This package was a redo of Example 5-6 and showed no defects.
• Example 3-9 Film #1 was unsuccessfully vacuum formed using Die Wl. The film shattered to bits.
• Example 3-10 Film #2 was successfully vacuum formed using Die #2 and about 24 grams of finely powdered ALLEGGRA® FS74 egg product was filled in the pouch. Film #4 was successfully used to close the package by heat sealing. This package was later found to have a leak due to a heat sealing defect.
• Example 3-1 1 - Film #5 was successfully vacuum formed using Die #3 and about 5 grams of finely powdered Crystal Light® Soft Drink Mix was filled in the pouch. Film #4 was successfully used to close the package by heat sealing.
• Example 3-12 Film #5 was successfully vacuum formed using Die #4 and about 5 grams of finely powdered Crystal Light® Soft Drink Mix was filled in each of seven pouches. Film #5 was successfully used to close the package by heat sealing. This film was capable of filling multiple adjacent cavities in a single vacuum forming operation.
• Example 3-13 Film #6 was successfully vacuum formed using Die #4 and about 4 grams of finely powdered Alpine® Spiced Cider Sugar Free Drink Mix was filled in each of seven pouches. Film #6 was successfully used to close the package by heat sealing. This film was capable of filling multiple adjacent cavities in a single vacuum forming operation.
• Example 3-14 Film #4 was successfully vacuum formed using Die #4 and about 5 grams of finely powdered Easy Mac® Cheese Powder was filled in each of seven pouches.
• Film #4 was successfully used to close the package by heat sealing. This film survived but seemed to be at the limit of its elongation and gave audible signs of stress during vacuum forming.
• Example 3-15 Film #3 was successfully vacuum formed using Die #1 and about 17 grams of finely powdered Easy Mac® Cheese Powder was filled in the pouch. Film #3 was successfully used to close the package by heat sealing.
• Example 3-16 Film #2 was successfully vacuum formed using Die #1 and about 17 grams of finely powdered Easy Mac® Cheese Powder was filled in the pouch. Film #3 was successfully used to close the package by heat sealing. This package was later found to have a leak due to a heat sealing defect.
• Example 3-17 Film #4 was successfully vacuum formed using Die #2 and about 40 grams of finely powdered Easy Mac® Cheese Powder was filled in the pouch. Film #4 was successfully used to close the package by heat sealing. This package was later found to have a leak due to a heat sealing defect.
• Example 3-18 Film #3 was successfully vacuum formed using Die #1 and about 17 grams of finely powdered Easy Mac® Cheese Powder was filled in the pouch. Film #3 was successfully used to close the package by water sealing.
• Example 3-19 - Film #5 was successfully vacuum formed using Die #5 and about 8 grams of finely powdered Easy Mac® Cheese Powder was filled in the pouch. Film #5 was successfully used to close the package by water sealing.
• Example 3-20 Film #3 (at 6 mil) was successfully vacuum formed using Die #5 and about 8 grams of finely powdered Easy Mac® Cheese Powder was filled in the pouch. Film #3 (at 6 mil) was successfully used to close the package by water sealing.
• Example 3-21 A blue colored and peppermint flavored film of 2 mil thickness was made using the following ingredients (all in % w/w, d.s. basis): pullulan (PI-20) 50%, tapioca dextrin (F4-800) 13%, glycerol 6%, propylene glycol 13%, and sorbitol 19%. The film was formed into a small Vi inch square pouch using a laboratory impulse sealer.
• Example 4 A 100 g film solution is prepared by dissolving 15.46 g pullulan in 80 g deionized water. To this 1.142 g glycerin, 2.28 g sorbitol, 0.572 g propylene glycol, 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, and 0.02 g sodium benzoate are added with stirring. Finally, 0.5 g gelatin-1385P was added with stirring. The solution is heated to 7O 0 C for 30 minutes to fully dissolve the gelatin. The solution is continually stirred as it cools to room temperature which keeps the gelatin in solution. The gel is degassed by either sitting overnight or centrifuging. The gels are then cast onto treated stainless steel and dried to a moisture level of 7.5-9.5%. The film can then be peeled from the steel.
• Example S A 100 g film solution is prepared by dissolving 14.76 g pullulan in 80 g deionized water. To this 1.334 g glycerin, 2.66 g sorbitol, 0.2 g propylene glycol, 1 g NaCl, 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, and 0.02 g sodium benzoate are added with stirring. The gel is degassed by either sitting overnight or centrifuging. The gels are then cast onto treated stainless steel and dried to a moisture level of 7.5-9.5%. The film can then be peeled from the steel.
• a 100 g film solution is prepared by dissolving 14.96 g pullulan in 80 g deionized water. To this 1.6 g sorbitol, 1.4 g polyethylene glycol, 2 g NaCl, 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, and 0.02 g sodium benzoate are added with stirring. The gel is degassed by either sitting overnight or centrifuging. The gels are then cast onto treated stainless steel and dried to a moisture level of 7.5-9.5%. The film can then be peeled from the steel.
• Example 7 Film samples prepared according to Examples 4-6 (labeled samples 4a, 5a, and 6a in the table below) were tested to determine their tensile strength and percent elongation to break. The same tests were also performed on comparison film samples (labeled as samples 4b, 5b, and 6b in the following table) that contained the same ingredients, except that they contained no gelatin or salt. Film Testing Protocol
• a sample of. film is placed between two aluminum blocks, which are held securely together by screws and wing nuts.
• the blocks have an identical pattern of five holes drilled through them.
• a cylindrical probe is attached to the arm of an Instron testing unit. The test is run by punching the probe through the film. Five repetitions are performed - one test per hole — without reloading the sample. The block is merely re-positioned to align a new hole with the probe. Calculations use the data averaged from all runs.
• the Instron software is programmed to start measuring when there is 1 gf recorded on the load cell, and records the distance the probe travels beyond this, through the hole drilled in the bottom plate. As the probe travels through the hole in the bottom plate, the film is distended and finally ruptures. As well as deformation, the instrument also records the resistance the film exerts over the course of deformation as gram force exerted on the load cell. Even though the film is being pushed rather than pulled in this test, the data can be treated as a conventional tensile test.
• Film strain can be determined as follows. The film is stretched between the tip of the probe and the supporting edge of the blocks.
• the initial "length" of the test sample is defined as the radius of the hole ("a").
• the distended length can be calculated from this initial length and the distance the probe has traveled.
• the distended length is essentially the hypotenuse of a right triangle, with the hole radius, a as one side of the triangle and distance traveled by the probe, b, as the second side.
• c (a 2 + b 2 )' /2 .
• Strain (distended length, c - 6.5)
• Percent elongation is the strain presented as a percentage rather than a fraction.
• the cross sectional area of the probe tip is 0.0085 cm 2 .
• the force at break or maximum load force is divided by the cross sectional area. Since the force is recorded in grams, it is then divided by 1000 to obtain the result in Kgf/sq cm. The calculation is as follows:
• Tensile Strength max. force (gf) / 0.0085 sq cm / 1000 Blocking Analysis
• a subjective test is used. For this test, three pieces of film are cut and placed overlapping, front-to-back on a piece of Mylar, and then covered with another piece of Mylar. A ' ⁇ -inch thick sheet of glass is placed on top of the stack in order to apply pressure to the films. After one week the films are peeled apart and scored as to ease of peel by the following scale: 0: Not blocking
• the data indicate that both gelatin and salt can improve elongation. While the gelatin films usually require some other additive to combat blocking, the gelatin does not make blocking worse than similar films with less elongation. The data also indicates that salt can drastically improve elongation, and when used with r lower levels of plasticizers, it can greatly improve blocking as well.
• a 100 g surfactant solution is made by dissolving 5 g of sodium stearoyl lactylate in 95 g isopropyl alcohol. This is then sprayed or mopped onto stainless steel in a thin even layer and the liquid allowed to evaporate. Film gels may then be cast onto the treated surface and dried.
• Example 9 A 100 g surfactant solution is made by dissolving 5 g of propylene glycol monostearate in 95 g isopropyl alcohol. This is then sprayed or mopped onto stainless steel in a thin even layer and the liquid allowed to evaporate. Film gels may then be cast onto the treated surface and dried.
• a 100 g surfactant solution is made by dissolving 5 g of sodium lauryl sulfate in 95 g deionized water. This is then sprayed or mopped onto stainless steel in a thin even layer and the liquid allowed to evaporate. Film gels may then be cast onto the treated surface and dried.
• Example 11 A 100 g surfactant solution is made by dissolving 5 g of Polysorbate-80 in 95 g deionized water. This is then sprayed or mopped onto stainless steel in a thin even layer and the liquid allowed to evaporate. Film gels may then be cast onto the treated surface and dried.
• a 100 g film solution is prepared by dissolving 14.96 g pullulan in 80 g deionized water. To this 2.26 g diglycerol, 2.26 g polyethylene glycol, 0.5 g NaCl, 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, and 0.02 g sodium benzoate are added with stirring. The gel is degassed by either sitting overnight or centrifuging. The gel is then cast onto the four different treated stainless steel sheets and dried to a moisture level of 7.5-9.5%.
• a 100 g film solution is prepared by dissolving 14.96 g pullulan in 80 g deionized water. To this 1 g diglycerol, 1 g polyethylene glycol, 3 g NaCl, 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, and 0.02 g sodium benzoate are added with stirring. The gel is degassed by either sitting overnight or centrifuging. The gel is then cast onto the four different treated stainless steel sheets and dried to a moisture level of 7.5-9.5%.
• a 100 g film solution is prepared by dissolving 14.96 g pullulan in 80 g deionized water. To this 2 g diglycerol, 2 g polyethylene glycol, 1 g KCl, 0.01 g sodium lauryl sulfate,
• a 100 g film solution is prepared by dissolving 14.96 g pullulan in 80 g deionized water. To this 2 g diglycerol, 2 g polyethylene glycol, 1 g Na 2 SO 4 , 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, and 0.02 g sodium benzoate are added with stirring. The gel is degassed by either sitting overnight or centrifuging. The gel is then cast onto the four different treated stainless steel sheets and dried to a moisture level of 7.5-9.5%.
• Film Sample 12-5 A 100 g film solution is prepared by dissolving 14.96 g pullulan in 80 g deionized water. To this 2.26 g diglycerol, 2.26 g sorbitol, 0.5 g NaCl, 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, and 0.02 g sodium benzoate are added with stirring. The gel is degassed by either sitting overnight or centrifuging. The gel is then cast onto the four different treated stainless steel sheets and dried to a moisture level of 7.5-9.5%. Film Sample 12-6
• a 100 g film solution is prepared by dissolving 14.96 g pullulan in 80 g deionized water. To this 1.5 g diglycerol, 1.5 g sorbitol, 2 g NaCl, 0.01 g sodium lauryl sulfate, 0.01 g
• Polysorbate-80, and 0.02 g sodium benzoate are added with stirring.
• the gel is degassed by either sitting overnight or centrifuging.
• the gel is then cast onto the four different treated stainless steel sheets and dried to a moisture level of 7.5-9.5%.
• Film 13-1 A 100 g film solution is prepared by dissolving 15.26 g pullulan in 80 g deionizei solution is heated to 70 0 C for 30 minutes to fully dissolve the gelatin. The solution is continually stirred as it cools to room temperature which keeps the gelatin in solution. The gel is degassed by either sitting overnight or centrifuging. The gels are then cast onto treated stainless steel and dried to a moisture level of 7.5-9.5%. The film can then be easily peeled from the steel for use.
• Film 13-2 A 100 g film solution is prepared by dissolving 15.76 g pullulan in 80 g deioni centrifuging. The gels are then cast onto treated stainless steel and dried to a moisture level of 7.5-9.5%. The film can then be easily peeled from the steel for use.
• Film 13-3 A 100 g film solution is prepared by dissolving 15.14 g pullulan in 80 g deionizec either sitting overnight or centrifuging. The gels are then cast onto treated stainless steel and dried to a moisture level of 7.5-9.5%. The film can then be easily peeled from the steel for use.
• Film 13-4 A 100 g film solution is prepared by dissolving 16.14 g pullulan in 80 g deionizec either sitting overnight or centrifuging. The gels are then cast onto treated stainless steel and dried to a moisture level of 7.5-9.5%. The film can then be easily peeled from the steel for use.
• Film 13-5 A 100 g film solution is prepared by dissolving 17.14 g pullulan in 80 g deionizi sitting overnight or centrifuging. The gels are then cast onto treated stainless steel and dried to a moisture level of 7.5-9.5%. The film can then be easily peeled from the steel for use.
• both gelatin and salt greatly improve the elongation of pullulan films.
• Films 13-1 and 13-2 which both contained 21% plasticizer, showed much different elongation values. Without the gelatin (film 2), the film has a break elongation of only 8.4%, while with gelatin, the break elongation increases to 150.3%.
• Films 13-3, 13-4, and 13-5 which all contain only 14% plasticizer, also show widely different elongations. At this low plasticizer level, little increase in elongation is seen with the addition of only 5% salt. However, when adding 10% salt the break elongation jumps to 1 10%. The strength was greatly reduced at these high levels of salt. In films with slightly higher levels of traditional plasticizers, the addition of 5% salt also gives much better elongation, as is seen in the previous examples.
• Example 14 A 100 g film solution is prepared by dissolving 15.56 g pullulan in 80 g deionized water. To this solution, 1.20 g glycerin, 3.2 g polyethylene glycol (PEG) 200, 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, and 0.02 g sodium benzoate are added with stirring. Stirring continues at room temperature until the gel is of uniform consistency. The gel is degassed either by sitting overnight or by centrifugation. The gel is then cast onto a stainless steel surface treated with 2% sodium stearoyl lactylate (SSL) dissolved in isopropanol. The cast film is dried to a moisture level of 7.5-9.5%. The film can then be readily peeled from the steel for evaluation and use.
• PEG polyethylene glycol
• SSL sodium stearoyl lactylate
• Example 15 A 100 g film solution is prepared by dissolving 15.36 g pullulan in 79.72 g deionized water. To this solution, 1.20 g glycerin, 3.2 g PEG 200, 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, 0.02 g sodium benzoate, and 0.48 g of a 41.5% paraffin wax emulsion are added with stirring. Stirring continues at room temperature until the gel is of uniform consistency. The gel is degassed either by sitting overnight or by centrifugation. The gel is then cast onto a stainless steel surface treated with 2% SSL dissolved in isopropanol. The cast film is dried to a moisture level of 7.5-9.5%. The film can then be readily peeled from the steel for evaluation and use.
• a 100 g film solution is prepared by dissolving 15.16 g pullulan in 79.44 g deionized water. To this solution, 1.20 g glycerin, 3.2 g PEG 200, 0.01 g sodium lauryl sulfate, 0.01 g Polysorbate-80, 0.02 g sodium benzoate, and 0.96 g of a 41.5% paraffin wax emulsion are added with stirring. Stirring continues at room temperature until the gel is of uniform consistency. The gel is degassed either by sitting overnight or by centrifugation. The gel is then cast onto a stainless steel surface treated with 2% SSL dissolved in isopropanol. The cast film is dried to a moisture level of 7.5-9.5%. The film can then be readily peeled from the steel for evaluation and use.
• a 100 g film solution is prepared by dissolving 20.447 g pullulan in 72.190 g deionized water.
• 1.080 g glycerin, 2.16O g PEG 200, 2.700 g sorbitol, 0.054 g of a 10% food grade silicone emulsion, 0.014 g Polysorbate-80, 0.027 g sodium benzoate, and 1.301 g of a 41.5% paraffin wax emulsion are added with stirring. Stirring continues at room temperature until the gel is of uniform consistency.
• the gel is degassed either by sitting overnight or by centrifugation.
• the gel is then cast onto a stainless steel surface treated with 2% SSL dissolved in isopropanol.
• the cast film is dried to a moisture level of 7.5-9.5%.
• the film can then be readily peeled from the steel for evaluation and use.
• a 100 g film solution is prepared by dissolving 15.36 g pullulan in 79.96 g deionized water. To this solution, 1.00 g glycerin, 2.40 g PEG 200, 1.20 g sorbitol, 0.04 g of a 10% food grade silicone emulsion, 0.01 g Polysorbate-80, and 0.02 g sodium benzoate. Stirring continues at room temperature until the gel is of uniform consistency. The gel is degassed either by sitting overnight or by centrifugation. The gel is then cast onto a stainless steel surface treated with 2% SSL dissolved in isopropanol. The cast film is dried to a moisture level of 7.5-9.5%. The film can then be readily peeled from the steel for evaluation and use.
• Example 14-18 are examples of wax-containing pullulan film formulations and their non-wax analogs.
• Polymer thin films can exhibit a tendency to self-adhere, or "block", under pressure. Films that do not exhibit this tendency can be cast and rolled onto themselves without backing or support.
• a procedure was developed for a relatively rapid and facile analysis: Three 1" squares were cut from a cast pullulan film and stacked on a Mylar sheet closed-side to open-side in a staggered configuration. The stacked samples were covered with a second sheet of Mylar to prevent adhesion of film squares to any other surfaces. Five 22" x 14" x 0.5" sheets of glass were placed on top of the lot of stacked samples to provide pressure similar to that experienced by film when rolled onto itself. The samples were checked after 24 hours to evaluate the level of surface blocking, or the degree to which the three squares of each sample adhered to one another. Any samples not irreversibly stuck together after 24 hours were reevaluated after a week total elapsed time.
• test results were expressed by assigning a score on a five-point scale: 0 - No surface adhesion
• Example 14 0 2 2
• Example 15 1 1 2
• Example 16 2 0 1
• Example 20 In many commercial packaging operations, film packages are heat-sealed to keep them closed. In order to measure the ability of pullulan films to seal with heat, the following test was performed. To this end, 2" x 0.5" strips of film were sealed together in three different orientations, then pulled apart by hand. Films were sealed open-face-to-open-face (front-to-front), closed-face-to-closed-face (back-to-back), and open-face-to-closed-face (front-to-back).
• Example 14 0 1 3
• Example 16 2 0 2
• the data in Table 8 indicate that the presence of wax in pullulan film formulations increases the ability of the film to form strong seals.
• the results also show that seals involving the closed surface of the film, indicated by "B" above, were not as good as seals made from open surface to open surface.
• the only difference between the closed and open surfaces of the film is the presence of SSL on the closed surface.
• SSL therefore, appears to be responsible for decreased seal strength when treated surfaces are involved. That decreased seal strength occurs only when the closed surface is involved is an indication that the SSL is immiscible with the aqueous casting gel and remains localized on the closed surface.
• the test follows ASTM Dl 894, and utilizes Bluehill 2 software for method control and analysis.
• a sled (2.5 in 2 , 200 g) is wrapped in the film to be tested, and placed onto the testing table.
• the testing table is covered with the desired test material.
• the table is covered with film to test the slip of film on film, and it is also covered with a stainless steel sheet (4.5"x 15") for testing the slip of the film on steel.
• the sled is then pulled along the table by a tow line at a rate of 150 mm/min.
• the tow line is attached to a load cell on the Instron via a hook assembly, which measures the force needed to pull the sled.
• the coefficient of friction is calculated by dividing the force necessary to pull the sled by the weight of the sled.
• the static coefficient of friction is the amount of force necessary to start the sled moving, and is calculated using the maximum force from the first peak.
• the dynamic coefficient of friction is defined as the force necessary to keep the sled moving and is calculated by averaging the force over the next 10 inches of testing, and dividing it by the sled weight. All calculations are carried out by the Bluehill 2 software.
• Promois WS hydrolyzed soy protein from Seiwa Kasei Co., LTD.
• Promois SIG hydrolyzed sesame protein from Seiwa Kasei Co., LTD.
• Promois Hydromilk hydrolyzed milk protein from Seiwa Kasei Co., LTD.
• the resultant gels were de-gassed, cast onto stainless steel and dried in an environmental chamber at 65 0 C, and a relative humidity of 25% for one hour and 15 minutes. At that time the chamber was reset to 22.5°C and a relative humidity of 45% for curing overnight. The films were then removed from the steel and tested. All were tested for tensile strength and elongation by the probe method on an Instron device, and moisture by Karl Fischer oven-method analysis.
• a test method named "quick dissolution analysis” was developed to quickly determine the dissolution properties of pullulan films.
• the method simply uses a stopwatch, stir plate, beaker, stir bar, and thermometer.
• the temperature of the water used is within the range of 5-15 0 C, and for the hot water test it is within the range of 65-75°C.
• a beaker of either hot or cold water is placed on a stir plate and stirred at a moderate pace. The temperature is measured with a thermometer and recorded.
• a piece of film, approximately one inch square in size, is cut and dropped into the water. The timer is started as soon as the film is in the water. The time at which the film is completely dissolved is recorded.
• the apparatus is cleaned and fresh water obtained before starting the next test.
• Example 24 A film that contains no salt was first made to use as a control. This film was made by dissolving 19.7125 g pullulan, 0.75 g glycerol, 2.5 g sorbitol, 2 g polyethylene glycol (200 MW), 0.0125 g sodium lauryl sulfate, and 0.025 g sodium benzoate in 75 g of water. The gel was cast onto stainless steel and dried in an environmental chamber at 65°C, and a relative humidity of 25% for one hour and 15 minutes. At that time the chamber was reset to 22.5°C and a relative humidity of 45% for curing overnight. The film was then removed from the steel and tested.
• Three films that contain 1.25% (dsb) of three different salts were made. These films were made by dissolving 19.4 g pullulan, 0.75 g glycerol, 2.5 g sorbitol, 2 g polyethylene glycol (200 MW), 0.0125 g sodium lauryl sulfate, 0.025 g sodium benzoate, and 0.3125 g of one of the following salts in 75 g of water.
• the gels were all cast onto stainless steel and dried in an environmental chamber at 65 0 C, and a relative humidity of 25% for one hour and 15 minutes. At that time the chamber was reset to 22.5°C and a relative humidity of 45% for curing overnight. The films were then removed from the steel and tested.
• the gels were all cast onto stainless steel and dried in an environmental chamber at 65°C, and a relative humidity of 25% for one hour and 15 minutes. At that time the chamber was reset to 22.5°C and a relative humidity of 45% for curing overnight. The films were then removed from the steel and tested.
• Films containing combinations of the salts NaCl and MgCl 2 in different proportions were prepared. These films were made as follows: a) This film was made by dissolving 19.0875 g pullulan, 0.75 g glycerol, 2.5 g sorbitol, 2 g polyethylene glycol (200 MW), 0.0125 g sodium lauryl sulfate, 0.025 g sodium 0 benzoate, 0.3125 g NaCl, and 0.3125 g MgCl 2 in 75 g of water. The gel was cast onto stainless steel and dried in an environmental chamber at 65°C, and a relative humidity of 25% for one hour and 15 minutes.
• Example 29 A pullulan film was cast and dried on a sheet of 2 mil polyester film.
• the dried pullulan film layer was about 4 mil in thickness and was allowed to remain attached to the polyester substrate.
• Two 4.5-inch wide rolls of this bilayered construction were loaded onto a Transwrap vertical form-fill-seal packaging machine such that the pullulan layer was on the inside (in contact with the fill material) and the polyester layer was on the outside.
• the heat- sealing jaws of the machine were set to a constant temperature of 125°C.
• the machine was actuated and the bilayered film construction was successfully formed into 4.5-inch by 5.5- inch pouches containing food grade fill material. Sealing of the pullulan layer to form the food pouch was successfully performed by heating through the protective polyester layer.
• the protective polyester film layer remained adhered to the finished pouches, but could be easily peeled off of the pouches before using the edible pouch and its contents for food preparation.

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