the present invention provides stable edible film formulations , containing aspartame , through the addition of acid to the film composition . moreover , the present invention provides methods for manufacturing edible films containing aspartame . it has been surprisingly found to be advantageous during thin film processing to add acid to the film formulation . pursuant to the present invention , aspartame containing stable , flavorful edible thin films can be formed by a variety of different processes . one such process is as follows : ( 1 ) an aqueous solution is formed by blending film - forming materials together with water and acid and are agitated until the powdered materials are preferably mostly hydrated and few lumps are present ; ( 2 ) to this mixture , plasticizers , softening agents , colors , sweeteners , cooling agents , and active ingredients are blended together to form a homogeneous solution ; and ( 3 ) this solution is then cast onto a suitable carrier , and dried to form a film . it should be noted that no particular order is placed on incorporating the ingredients into the mixture ; however , it is important that the acid is included in the solution before the aspartame is added . it should also be noted that a wide variety of film formulations or coating syrups can be used . as part of the process , preferably , a carrier is used to produce edible films . the carrier material should be impermeable to the film coating , allowing the film coating to disperse evenly onto the carrier and allowing for the ease of removal of the film from the carrier . examples of suitable carriers include plastic or polyester films , polypropylene , polycarbonate , non - siliconized polyethylene terephthalate film , non - siliconized kraft paper , polyethylene impregnated kraft paper , metal belts , voltage or corona treated belts , drum dryers , and polytetrafluroethylene - impregnated glass fabric . a particularly preferred method of casting the film on the carrier is through a slot die extrusion . by use of multiple extruders and specially constructed dies , it is possible to add multiple color stripes to the product . it is also possible to oscillate the die head to produce wavy lines on the product . the resulting films can be laminated to produce various visual effects . the casting of the solution onto a suitable carrier material can be performed using any conventional coating technique . examples of coating techniques include spraying , dipping , comma coaters , knife over plate , roll over roll , reverse roll , slot die extrusion , and various extrusion techniques . film thickness can be controlled by adjusting the gap on the coating head , or by applying the desired amount of the solution onto the substrate / carrier . no particular limitation is placed on the thickness of the film layer . the thickness of the film may vary , or a multi - layered film product may be processed , depending on the desired speed of dissolution of the edible film while in the oral cavity . after coating , the film passes through a dryer for moisture reduction . drying is carried out through a variety of different means , such as high velocity turbulent hot air , conduction from steam heated slide bed , direct heating or casting of film onto a heated drum or belt , hot or cold air impingement , infrared heating , or any other suitable drying equipment that does not adversely affect the components of the film . once the film exits the drying system , the dried film is either taken - up along with its substrate or peeled from the carrier to form a wide roll . as the film exits the drying system , it can be exposed to a number of different types of treatments . if desired , the film may be sprinkled with sugar , starch , flavor , color , color enhancers such as glitter , acids , bioadhesives , actives and texturizers such as candy sprinkles to make specialty edible film products that may be desirable to younger consumers . after the film has been dried and treated as desired , it may be cut , stamped , etched , punched , etc ., into its final chosen size and form . for example , the edible film can be a rolled edible film . rolled edible films and methods of making the same are disclosed in u . s . patent application ser . no . 10 / 228 , 742 , entitled “ rolled edible thin film products and methods of making the same ,” filed on aug . 27 , 2002 , the disclosure which is incorporated herein by reference . the formulations of the present invention may be used to generate “ specialty ” films that can be produced at various points during the film making process . for example , those concepts which appeal to younger consumers . types of specialty film products include , but are not limited to films that are multi - flavoring , multi - layering , multi - coloring , multi - shapes or forms , texturizing , laminating , printing , graphical designs , “ tongue - tattoos ”, oral sensations , varying dissolution profiles , bioadhesive components , within the oral mucosa of a consumer ; alone or in combinations thereof . the films of the present invention are also suitable for food applications beyond direct consumption . any suitable water - soluble , film - former can be used to produce a rolled edible thin film product . suitable film - formers include , but are not limited to , water - soluble non - starch polysaccharides such as modified celluloses , carboxymethylcellulose ( cmc ), methylcellulose , hydroxypropylmethylcellulose ( hpmc ), hydrolyzed gums , xanthan gum , guar gum , locust bean gum , tamarind , agar agar , carrageenan , algins , gum arabic , ghatti gum , karaya gum , tragacanth gum , konjac , arabinogalactan , larch arabinogalactan , beta - glucan , propylene glycol , pullulan , levan , elsinan , pullulan , pectins , curdlan , chitosan ; native starches such as corn starch , waxy maize starch , high - amylose corn starch , potato , tapioca , rice and wheat starch ; modified starches such as those that have been acid modified , bleached , oxidized , esterified , etherified , crosslinked , and treated enzymatically ; starch hydrolyzed products such as maltodextrin ; protein such as gelatin , casein , salts of casein , whey , and protein derived from soybeans ; polymers such as polyvinyl pyrrolidone , methycrylate copolymer , and carboxyvinyl copolymers alone or in any combination . in an embodiment , the concentration of the film - forming agent constitutes between approximately 5 % to about 60 % by dry weights , or approximately 20 % to about 40 % by dry weight of the final film composition . further , it should be noted that some film forming agents , such as sodium alginate , will have an impact on the ph of the edible film composition . further , any suitable food - grade bulk filler can also be added to the film . this can reduce any “ slimy ” texture as well as provide structure to the film making it more palatable . in an embodiment , the filler can constitute approximately 1 % to about 30 % by dry weight of the film , or approximately 5 % to about 15 % by dry weight of the film . the filler can include microcrystalline cellulose , cellulose polymers , such as wood , magnesium and calcium carbonate , ground limestone , silicates , such as magnesium and aluminum silicate , clay , talc , titanium dioxide , mono - calcium phosphate , di - calcium phosphate , tri - calcium phosphate , other like bulk fillers or combinations thereof . if it is desired to use reduced levels of film forming agents , softeners can also be employed to ensure the flexibility of the film , thereby reducing brittleness . the softeners , which are also known as plasticizers , may include tallow , hydrogenated tallow , hydrogenated and partially hydrogenated vegetable oils , cocoa butter , sorbitol and other polyols , glycerin , polyethylene glycol , propylene glycol , invert sugars , corn syrup , lecithin , hydrogenated lecithin , mono -, di - and triglycerides , acetylated monoglycerides , fatty acids ( e . g . stearic , palmitic , oleic , and linoleic acids ), and combinations thereof . in an embodiment , the softener can constitute 0 % to about 20 % by dry weight of the film , or approximately 2 % to about 10 % by dry weight of the film . another means of controlling the brittleness of the film is to maintain an adequate moisture level in the film . preferably , moisture levels should range from approximately 5 % to about 20 % or approximately 10 % to about 15 % of the final film product . pursuant to the present invention , a variety of acids can be used to maintain the stability of the aspartame during processing or to enhance the flavor of the film . these acids include , but , are not limited to malic , fumaric , adipic , succinic , citric , acetic , lactic , pyruvic , butyric , formic , isocitric , lactocitric , shikimic , quinic , oxalic , glyceric , citramalic , glycolic , glucuronic , galacturonic , aspartic , benzoic , lactarimic , cetostearic , allantoic , pyroglutamic , hydrochloric , hexanoic , carbonic , sulfuric , pyrrolidinonecarboxylic , and tartaric . further , acids may be added to impact the flavor of the product . for example , malic acid is commonly associated with apples , citric acid with lemons , and tartaric acid with grapes . however , mixtures of different acids may be used in combination to create a desired taste or flavor . further , these acids may be encapsulated to control their rate of release and interaction with the other components of the film matrix . a variety of other suitable ingredients can be added to the edible film of the present invention . for example , any suitable medicament for oral cleansing , breath freshening or the like can be added to the film formulation . the medicaments can include , for example , ph control agents , tartar caries control , whitening agents , enzymes , breath freshening agents , anti - plaque / anti - gingivitis agents , saliva stimulating agents , pharmaceutical agents , nutraceutical agents , vitamins , mineral , other like medicaments or combinations thereof . the edible film formulations or coating syrups of the present invention can also include colorants or coloring agents that can be used in any suitable amount to produce a desired color . further , the rolled films of the present invention , if desired , can include colored stripes and / or other related designs or shapes to produce color contrasts on the edible rolled film . coloring agents can include , for example , natural food colors and dyes suitable for food , drug , and cosmetic applications . the colorants are typically known as fd & amp ; c dyes and lakes . a variety of flavoring agents can also be added to the edible films . any suitable amount and type of artificial and / or natural flavoring agents can be used in any sensorially acceptable fashion . for example , the flavor can constitute approximately 0 . 1 % to about 20 % by dry weight of the film , preferably approximately 10 % to about 15 %. the flavoring agent can include , for example , essential oils , synthetic flavors or mixtures including but not limited to oils derived from plants and fruits such as citrus oil , fruit essences , peppermint oil , spearmint oil , other mint oils , clove oils , oil of wintergreen , anise and the like , flavor oils with germ killing properties such as menthol , eucalyptol , thymol , like flavoring agents or combinations thereof . the flavor can be enhanced and distributed evenly throughout the product by emulsification . any suitable amount and type of natural and / or synthetic food - grade emulsifier can be used . for example , the emulsifier can include lecithin , food - grade non - ionic emulsifiers , such as fatty acids ( c 10 - c 18 ), mono and diacyl glycerides , ox bile extract , polyglycerol esters , polyethylene sorbitan esters , propylene glycol , sorbitan monopalmitate , sorbitan tristerate , other like emulsifiers or combinations thereof . the flavors can be emulsified by any suitable emulsification process , such as mechanical processing , vigorous stirring , intense pressure fluctuations that occur in turbulent flow such as homogenization , sonification , colloid milling and the like . further , flavors may also be encapsulated or spray dried onto the rolled edible film product to enhance flavor properties or to add texture to the film composition . any suitable amount of sweetening agents may also be employed for the present invention . sugar sweeteners generally include saccharide - containing components including but not limiting to , sucrose , dextrose , maltose , dextrin , invert sugar , fructose , levulose , galactose , corn syrup solids , and the like , alone or in any combination . sugarless sweeteners include , but are not limited to , sugar alcohols such as sorbitol , mannitol , xylitol , isomalt , hydrogenated starch hydrolysates , maltitol , and the like , alone or in any combination . however , the low weight of the film products of the present invention generally render these low intensity sweeteners ineffective for purposes of sweetening although they may provide functional benefits . high intensity artificial sweeteners are preferably used , alone or in combination with the above . preferred sweeteners include , but are not limited to , sucralose , aspartame , n - substituted apm derivatives such as neotame , salts of acesulfame , alitame , saccharin and its salts , cyclamic acid and its salts , glycyrrhizin , dihydrochalones , thaumatin , monellin , and the like , alone or in any combination . in order to provide enhanced or delayed sweetness , or to provide texture to the rolled film product , it may be desirable to encapsulate the sweetener . such techniques as wet granulation , wax granulation , spray drying , spray chilling , fluid bed coating , coacervation , and fiber extension may be used to achieve the desired characteristics . combinations of sugar and / or sugarless sweeteners may be used in the film product . additionally , a softening agent may also provide additional sweetness such as with aqueous sugar or alditol solutions . cooling agents may also be employed in the present invention , cooling agents include , but are not limited to , menthol , ws3 , ws23 , utracool , monomenthyl succinate , alone or in any combination . again , these cooling agents may be encapsulated or spray dried onto the film to enhance a variety of oral sensations . depending on the ingredients being used to make the film product , preservatives may also be employed to ensure the safety and quality of the edible thin film . suitable preservatives include but are not limited sorbic acid , sodium benzoate , potassium sorbate , methyl p - hydroxybenzoate , sodium propionate , and propyl p - hydroxybenzoate alone or in any combination . in addition , suitable antioxidants can be used . it should be appreciated that any suitable type , number and arrangement of process procedures or steps ( e . g . mixing , heating , drying , cooling , addition , of ingredients ), process parameters ( e . g . temperature , pressure , ph , process times ) or the like can be utilized to practice the present invention . by way of example and not limitation , examples of the present invention will now be given . a ) powdered materials ( such as film forming agents ) are blended together using a ribbon blender or equivalent b ) flavors or flavor components / enhancers are blended together using mechanical agitation or equivalent . a ) the mixing tank is turned on and set at desired temperature . c ) water is added to the mixing tank , and begin agitation of the mixing tank . d ) when all water has been added , the desired acid is added . e ) once all blended powders and acid have been added to the mixing tank , sweeteners , flavors , colors , etc . are added as the temperature rises . the blend is maintained at an even temperature , about 105 to about 115 ° f . the conditions of the mixing room are maintained at about 70 to about 80 ° f ., 40 to about 50 % rh . b ) upon entering the drying system , the film solution is coated onto a moving substrate which passes under a coma bar roll to produce a dry thickness of about 48 to about 52 microns . c ) adjust the heater temperature to achieve an exit film temperature of about 215 to about 220 ° f . this should produce a film having a moisture of about 9 to about 11 %. d ) drying room conditions are about 70 to about 80 ° f ., 40 to about 50 % rh . a ) the film is removed from the substrate upon exiting the drying system and taken up on a separate roll . once the rolled dried film cools and sets , it is unwound and cut into its desired final form . through quality assurance testing , it was discovered that after the edible films had been processed , the loss of aspartame was in a range of about 20 to about 40 % in the final product after processing . several tests were run , incorporating acid into the film composition in order to decrease or stop the losses of aspartame in the final film product . the formulas used and the results from the tests run are as follows : % finished weight ingredient control comparative example 1 alginate 32 . 0 32 . 0 maltodextrin 17 . 0 17 . 0 carrageenan 12 . 0 12 . 0 cellulose 10 . 0 10 . 0 glycerin 8 . 5 8 . 5 aspartame 1 . 0 1 . 0 citric acid — 0 . 15 flavor 8 . 0 8 . 0 menthol 1 . 5 1 . 5 water 10 . 0 9 . 85 total 100 . 0 100 . 0 a syrup holding test was conducted to demonstrate aspartame degradation in the holding tank before the solution was processed and dried to form the final film product . syrup was made with and without citric acid and placed in an oven at 125 to about 133 ° f . samples of syrup were taken at 0 , 2 hr , 5 hr , 24 hr , 48 hr , and 76 hr . aspartame levels were tested , and the results are as follows : control example 1 time of sampling (% aspartame (% aspartame ( hrs .) retained ) retained ) t = 0 100 % 100 % t = 1 92 . 0 % 100 . 0 % t = 5 87 . 0 % 98 . 0 % t = 24 61 . 0 % 92 . 0 % t = 48 44 . 0 % 81 . 0 % t = 76 34 . 0 % 73 % the data above demonstrates a significant retention of aspartame while in acidic solution over time . the control sample experienced a 66 % loss of aspartame over a 76 hour period of time . in contrast , example 1 ( containing citric acid ) experienced only a 27 % loss of aspartame over the given period of time . dried syrup ( final film product ), was also tested for aspartame levels in the finished product . random samples were taken off the dried film role in the beginning , middle , and end regions of the roll . aspartame levels were determined from each region , and results are as follows : sampling control example 1 region (% aspartame (% aspartame of the roll retained ) retained ) beginning 76 % 100 % middle 66 % 100 % end 40 % 98 % the data above demonstrates a significant loss of aspartame over time ( approximately 5 hours to complete the entire processing run ). the control sample experienced a 60 % loss of aspartame over the five hour period , whereas example 1 ( containing citric acid ) only lost 2 % aspartame . the following examples illustrate some embodiments of the invention . of course , may others are possible and are easily formulated by a skilled technician once the fundamental concepts of the invention are grasped . [ 0091 ] (% finished wt .) ingredient ex . 2 ex . 3 ex . 4 ex . 5 ex . 6 ex . 7 corn starch 24 . 8 — — 30 . 0 — — hydroxypropylated starch — — — — — 47 . 35 carrageenan 14 . 0 12 . 0 10 . 0 — 9 . 0 — glycerin 10 . 0 8 . 0 — 5 . 0 9 . 0 7 . 50 gelatin — — 12 . 0 5 . 0 — 2 . 50 microcrystalline cellulose 3 . 0 7 . 0 — 5 . 0 8 . 0 — sodium alginate — 25 . 0 10 . 0 5 . 0 30 . 0 22 . 0 maltodextrin — 20 . 5 — — 18 . 0 — pullulan 6 . 0 — 39 . 0 — — — sorbitol 15 . 0 — — 5 . 0 — — liquid sorbitol — — — 10 . 0 — — acesulfame k — — — — — 1 . 0 sucralose — 1 . 45 1 . 0 1 . 0 — 1 . 25 aspartame 1 . 50 — 2 . 0 — 2 . 0 — ws - 3 — 1 . 55 — 1 . 0 — — ws - 23 — — 2 . 0 — — — menthol — 6 . 0 1 . 0 — 3 . 0 1 . 0 spearmint — — — — 6 . 0 — cherry flavor 15 . 0 5 . 0 — 12 . 0 — — peppermint — — — — 6 . 0 — eucalyptol — — — — — 6 . 00 methyl salicylate — 4 . 8 10 . 0 — — — citric acid — 0 . 1 — 5 . 0 1 . 0 — adipic acid — — 1 . 0 — — 1 . 00 phosphoric acid 0 . 2 0 . 1 — — — — color 0 . 50 0 . 50 — 0 . 50 0 . 35 0 . 40 water 10 . 0 8 . 0 12 . 0 15 . 5 7 . 65 10 . 0 total 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 ingredient ex . 8 ex . 9 ex . 10 ex . 11 ex . 12 ex . 13 hydroxyethylated starch — 48 . 0 — — — — pure - cote ® b790 * 50 . 0 — — — — — enzyme hydrolyzed corn starch — — 22 . 0 — — — maltodextrin — — 5 . 0 28 . 0 — — casein — 2 . 9 — — 3 . 5 — pullulan — — 20 . 0 — — 35 . 0 polyvinyl pyrollidone — 11 . 0 — — 6 . 0 — hydroxypropylmethylcellulose — — — — 30 . 0 — xanthan gum — — — — — 6 . 0 locust bean gum — — — — — 8 . 0 glycerin — — — 12 . 0 9 . 5 10 . 5 polyethylene glycol — — — — 6 . 0 — propylene glycol 1 . 50 — 10 . 0 — 6 . 0 — carrageenan — 11 . 0 — 10 . 0 — 24 . 7 sodium alginate — — — 13 . 75 — — calcium alginate 22 . 9 — — — — — silica — — — 5 . 0 — — calcium carbonate — — 3 . 0 — — — pectin 4 . 0 — — — — — lecithin — 2 . 0 1 . 0 1 . 5 — — saccharin — — — — — 2 . 0 aspartame 0 . 25 — — 1 . 0 1 . 5 — sucralose 1 . 25 — — — — — neotame — — 0 . 50 — 1 . 5 — encapsulated acesulfame k — — 1 . 5 — 1 . 0 — corn syrup — — 15 . 0 — — — guar gum — 2 . 0 — — — — sorbitan monopalmitate — — — — 4 . 0 — ultracool — — — 1 . 2 — 5 . 0 citric acid — — — 1 . 5 — — adipic acid — — — 1 . 5 — — methyl salicylate — — — — — 1 . 5 eucalyptol — 6 . 0 — — — 0 . 5 thymol — — 2 . 8 — — 0 . 5 encapsulated peppermint — — — — 11 . 0 — menthol — — 8 . 0 — 4 . 0 1 . 5 lemon flavor 10 . 0 — — 8 . 0 — — mixed berry flavor — 5 . 0 — 8 . 0 — — fumaric acid 1 . 0 0 . 05 — 0 . 1 — — tartaric acid — — 0 . 1 0 . 1 — 0 . 30 citric acid — — 0 . 1 0 . 1 1 . 0 — color 0 . 05 0 . 05 0 . 50 0 . 25 — 0 . 5 water 9 . 05 12 . 0 10 . 5 8 . 0 15 . 0 4 . 0 total 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 ingredient ex . 13 ex . 14 ex . 15 ex . 16 ex . 17 ex . 18 ex . 19 ex . 20 hydroxypropylcellulose 45 . 0 — — — — — 18 . 0 — waxy maize starch — — — — — — 15 . 0 — potato starch 2 . 0 — 29 . 5 — — — — — pullulan — 26 . 0 8 . 0 — 55 . 0 — — — microcrystalline cellulose — — 10 . 0 6 . 5 — 8 . 0 — 6 . 5 sorbitan fatty acid ester — — 1 . 0 — — — 3 . 0 — maltodextrin — 19 . 0 — 20 . 0 — 28 . 0 — 19 . 0 carrageenan — 16 . 0 — 10 . 0 — 8 . 0 1 . 5 10 . 0 gelatin 7 . 0 — — — 2 . 0 — — — polyvinyl alcohol 5 . 85 — — — — — — — sodium polyacrylate 5 . 0 — — — — — — — carboxymethylcellulose 5 . 0 — — — — — — — xanthan gum — 3 . 0 — — — — — — karaya gum 3 . 5 — — — 6 . 0 — — — glycerin — — — 6 . 0 — 4 . 5 — 6 . 0 titanium dioxide — — 2 . 0 — — — 2 . 5 — sodium alginate — — — 25 . 0 2 . 0 20 . 5 13 . 0 19 . 0 sorbitol — — 1 . 5 — — 0 . 05 — — encapsulated aspartame — — — — — — 1 . 0 — sucralose — — — — — 1 . 5 1 . 0 3 . 0 corn syrup — — 15 . 4 — — — — — soybean oil — — 1 . 0 — — — — — lecithin — — — 1 . 5 0 . 5 0 . 50 — 1 . 5 dextrose — — 2 . 0 — — — — — fructose — 9 . 5 — — 5 . 0 — — — ws - 3 — 2 . 9 — 1 . 0 — — 4 . 0 0 . 5 clove oil — — 1 . 0 — 4 . 5 — — — menthol 8 . 0 2 . 0 — 2 . 0 — — 1 . 0 0 . 5 grape flavor — — — — — — 12 . 0 5 . 0 lemon flavor — — — — — 5 . 0 — — rose oil — 2 . 0 — — — — 1 . 0 — pepper — 2 . 0 — — — — — — orange flavor — — 3 . 0 — — 4 . 0 2 . 0 — peppermint oil — — — 9 . 0 5 . 0 2 . 0 — — cardamom 8 . 0 2 . 0 — — — 1 . 0 — — grapeseed extract — — — 5 . 2 2 . 5 — — — tea catechins — — — — — 1 . 0 — — vitamin c — — 3 . 0 — 2 . 5 — 5 . 0 9 . 9 vitamin a , b , d , e complex — — — — — — — 5 . 0 zinc gluconate — — — — — — 5 . 0 1 . 0 succinic acid — 0 . 2 — — — 1 . 5 — 0 . 001 tartaric acid 0 . 15 — — 1 . 0 — — — 3 . 0 encapsulated citric acid — 0 . 3 2 . 0 — — 5 . 0 5 . 0 — echinacea — — 3 . 0 — 2 . 5 1 . 0 — — cetyl pyridinium chloride 3 . 0 — — — — — — — encapsulated caffeine — 5 . 0 — — — — — — sodium benzonate — — — 2 . 0 0 . 5 — — — bha — — — 0 . 5 — 0 . 05 — — color 0 . 5 0 . 1 0 . 6 0 . 30 0 . 5 0 . 80 0 . 1 0 . 1 water 7 . 0 10 . 0 17 . 0 10 . 0 11 . 5 7 . 6 9 . 9 9 . 999 total 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 100 . 0 it should be appreciated that various changes and modifications of the presently preferred embodiments described herein will be apparent to those skilled in the art . such changes and modifications can be made without departing from the original spirit and scope of the present invention without diminishing its intended advantages . it is therefore intended that such changes and modifications be covered by the appended claims .
methods of producing edible thin film products and products so produced are provided . the method comprising the steps of : adding to a film formulation a food grade acid ; and adding aspartame to the film formulation and acid .