PROCESS FOR SWEETENING INDENTED CHEWING GUM WITH AN L-ASPARTIC ACID SWEETENING DERIVATIVE

Abstract: The sweetness of a chewing gum containing aspartame is stabilized by applying the aspartame into indentations made in the chewing gum surface.

Description: IMPRINTING PROCESS FOR SWEETENING CHEWING G@M .4ITH AN L-ASPARTIC ACID SWEETENING DERIVATIVE AND PRODUCTS OF IMPROVED SWEETNESS STABILITY OBTAINED THEREBY This invention relates to a method for sweetening chewing gum with an L-aspartic acid sweetening derivative and to products obtined thereby. Aspartame, L-aspartyl-L-phenylalanine methyl ester, a derivative of .;-aspartic acid, has recently been approved by the Food and Drug Administration as a natural sweetener for use in food. It ordinarily is unstable when incorporated in chewing gum. Aspartame decomposes in the presence of moisture and reacts with aldehyde-containing flavorings, such as cinnamon, over extended periods of time. Thus, chewing gum compositions obtained by admixing the aspartame with gum base and other chewing gum ingred@ents prior to the conventional rolling and extrusion steps exhibit substantial loss of sweetening. To obtain acceptable sweetening levels over extended periods, an inordinate amount oi aspartame must be used to compensate for subsequent losses. Attempts have bee: made to protect aspartame from moisture and gum components by encapsulating a solid aspartame with coating materials such as cellulose ethers, cellulose esters, edible vinyl polymers, gelatin, and the like, as disclosed ln U.S. Patent 4,384,004, U.S. Patent 4,122,195 and U.S. Patent 4, 139,539. However, even when encapsulated aspartame is incorporated into the gum, substantial decomposition of the aspartame results. It is believed that the integrity of the encapsulation is: 1) physically destroyed during mixing, and 7 ) destroyed by dissolutIon Into gum ingredients Juen as plasticizers. Decomposition of the aspartame over time could also result from migration of gum components through the encapsulant. In U.S. Patent 4,374,858 the sweetness stability of asp8rtame in chewing gum is Improved by applying onto the surface of the chewing gum piece a dusting of a material comprising aspartame. The aspartame is applied in pure powdered form, in encapsulated form or combinations thereof. The dusting can be by means of gravity flow from a helical auger or rollers. However, drawbacks in coating the aspartame onto the chewing gum surface in dry form in the manner taught by U.S. Patent 4,374,858 are: 1) physical loss of the aspartame from the surface during subsequent material handling steps such as transport of the coated gum to wrapping equipment and the wrapping operation, 2) inconsistent control of the amount of aspartame applied to the gum surface and 3) an undesirably strong initial sweetness impact. The present invention provides an economical process for sweetening chewing gum with an L-aspartic acid sweetening derivative, such as L-aspartyl-L-phenylalanine methyl ester (aspartame) which achieves accurate and consistent control over the amount of the sweetener applied to the chewing gum minimizes physical loss of the sweetener during subsequent material handling steps, and minimizes decomposition of the sweetener during both chewing gum manufacture and storage of the finished product. The aspartame sweetened gum of the present invention does not contain "hot spots" due to high concentrations of the sweetener in or on the chewing gum. An acceptable level of sweetness is exhibited by the products during their shelf lives of at least about six months. The present invention relates to a process for the production of chewing gum having an L-aspartic acid sweetening derivative, such as L-aspartyl-L-phenylalanine methyl ester (aspartame) in an amount which provides an acceptable level of sweetness. Decomposition of the L-aspartic acid sweetening derivative during and after gum manufacture is avoided by applying it into one or more indentations in the chewing gum. The aspartame applied may be in pure powder form or encapsulated form or both. The amount of aspartame applied to the indented gum surface is sufficient to provide an aspartame'content of less than about 0.3X by weight, preferably from about .1S to about .25Z by weight based on the total weight of the final gum product. Aspartame within the indentations is protected from physical loss due to subsequent cutting, transport and wrapping. The indentations provide for accurate and consistent control over the amount of aspartame on the gum surface. The aspartame in the indentations does not result in an obJectionably high level of initial sweetness because: 1) the surface area of the aspartame which is exposed initially to the taste buds is small compared to the exposed surface area obtained by dusting the aspartame onto a flat gum surface, and 2) the indentations hold the aspartame on the gum by preventing lateral movement of the aspartame across the gum surface. The aspartame sweetened gum of the present invention exhibits an acceptable level of sweetness during an extended shelf life of at least about six months. The sweetener used in the present invention is preferably L-aspartyl-L-phenylalanlne methyl ester, known as aspartame. Other L-aspartic acid sweetening derivatives may also be used. Such derivatives are disclosed in U.S. Patent 3,955,000 at column 3, line 63 to column 4, line 35, the disclosure of which is incorporated herein by reference. The following description will be directed to aspartame with the understanding that other L-aspartic acid sweetening derivatives are included as well. The amount of aspartame applied onto the chewing gum either singly or in combination with other sweeteners present in the gum should be sufficient to produce an acceptably sweet chewing gum. In general, the aspartame applied on the chewing gum surface amounts to less than about 0.3% by weight, preferably from about 0.1% to about 0.25% aspartame by weight based on the total weight of the final gum product. It is found that for the same sweetening effect, the amount-of aspartame when applied to a gum surface with indentations is about one-third of that amount needed for an equivalent sweetening effect when incorporated into the gum composition. The aspartame which is used may be in pure powdered form, encapsulated form or both. The above percentages of aspartame are based upon the weight of aspartame without the encapsulant. Suitable, commercially available encapsulated forms include starch, polyvinyl acetate, gum arabic, and fat encapsulated aspartame. Encapsulated aspartame generally contains from about 10% to about 90% by weight aspartame, more typically about 20% to about 50% by weight aspartame, based upon the weight of the encapsulated aspartame. Sweeteners including natural sugars, sugar alcohols and artificial sweeteners and. lubricants can be used in conventional amounts, alone or in mixtures, as dusting materials or agents to prevent the gum from sticking to equipment during processing. The sweeteners, in combination with the aspartame, are used in amounts which provide an acceptable level of sweetness. Suitable sugar alcohols include mannitol, sorbitol and the like, or mixtures of the above. The lubricants are those conventionally employed in chewing gum manufacture such as calcium carbonate, talc or starch. As in conventional manner, the dusting materials or agents wre applied to the chewing gum prior to and preferably during te first rolling step. Excess dusting materials or agents can be removed by a rotating brush and a vacuum exhaust system for recycle to the dusting operation. The dusting materials or agents should be applied and the excess exhausted or otherwise removed prior to formation of the indentations. The indentations are then more available to the aspartame and excessive reduction of cohesiveness of the aspartame in the indentations due to lubrication is avoided. It is preferable to blend additional amounts of at least one dusting material with the aspartame prior to application of the aspartame into the indentations. The amount of aspartame retained in the indentations however, should be sufficient to impart an acceptable level of sweetness to the chewing gum. Blending of the aspartame with at least one dusting material can be used to control the distribution of aspartame and rate of the release of the aspartame from the indentations to avoid objectionable initial sweetening responses. For example, for a given indentation depth and a given amount of ' aspartame, blending it with a dusting agent-would require more indentations to accommodate the blend. The indentations may be produced by rollers having rows of solid projections on their surfaces. These embossing or imprinting rollers pass over the gum, leaving identical impressions thereon. The indentations may be produced as part of the conventional rolling operation for production of gum slabs having a desired thickness. Preferably, however, the indentations are applied to the gum after it has been rolled into sheets. The indentations on the sheet can be made before or after cutting the sheet into strips or even after cutting the strips into the final gum piece size. However, indentation of the sheet prior to any cutting is preferred for easier material handling and lower losses or less recycling of aspartame. Indentations in extruded gum can be made by the extruder die qr by rolling the extruded gum with rollers having projections. The indentations can be applied to one or more of the gum surfaces but preferably to only one surface. The embossing roller can be electrostatically charged for holding of the aspartame and optional dusting materials on the projections. The gum is provided with an opposite charge with conventional means. As the charged embossing roller, having a positive charge for example, rotates into the oppositely charged gum surface, the aspartame and optional dusting material is electrostatically transferred into the indentations. The depth, number and size of projections are not critical but they should be sufficient to hold an amount of aspartame which provides an acceptable level of sweetness without an objectionable initial sweetness impact. Generally, the amount of surface area provided by the indentations is less than about 10X, more typically less than about 5%, of the total surface area of the gum piece. The indentations are preferably placed substantially uniformly across the gum piece surface to assure the attainment of a substantially uniform sweetening response and the avoidance of hot spots" or excessive local concentra tions of the aspartame. Even though the aspartame is considerably concentrated in the indentations, the sweetened chewing gum of the present invention exhibits a substantially uniform and pleasant sweetening response because the surface area of the aspartame exposed to the taste buds is initially low and as the gum is chewed, the aspartame becomes incorporated into the gurr composition. Additionally, the aspartame within the indentations is more tightly held than is aspartame on a flat gum surface because the side walls of the indentations prevent lateral movement of the aspartame. The depth of the indentations suitably may range from about one-tenth to about one-half of the thickness of the gum pieces but must not perforate the gum pieces. The indentations may be in the shape of grooves, circles, squares, semi-circles, "C-shaped", a shape representing a trademark or the like. Grooves are preferred for simplicity. The aspartame, or a blend of at least one dusting material with aspartame can be transported by a helical auger or belt conveyor to a vibrating screen having mesh openings which permit gravity flow of the aspartame particles or blend of dusting materials and aspartame onto the moving gum slab underneath. The aspartame and optional dusting materials can also be applied by conventional dusting rollers. The rollers used to form the indentations can also be used to simultaneously apply the aspartame. The embossing roller can be electrostatically charged, as indicated above, or uncharged. The aspartame is preferably applied only to the projections on the roller which directly transfer the aspartame and optional dusting material into the indentations. Commercially available embossing or imprinting machines and dusting machines can be used to carry out the present invention. The aspartame and optional dusting materials which are not within the indentations can be left on the gum surface or can be transferred into the indentations by a rotating or stationary brush, by a roller, or combinations thereof. Preferably substantially all of the aspartame applied to the chewing gum composition 18 within the one or more indentations. The indentations can be partly or substantially completely filled. Once the indentations are filled with aspartame and optional dusting materials some of it will be retained by the raised portions of the chewing gum surface. However, excess, loosely held aspartame and optional dusting materials will be removed by the brushes or rollers. The portion which is removed from the gum surface can be recycled for application to fresh gum slabs. Conventional vacuum exhaust systems can be used to recycle the excess aspartame and optional dusting materials. An optional roller can then be used to press into the indentations any aspartame or dusting materials which is on the raised portions of the gum or which protrude from the indentations. The chewing gum compositions contemplated by the present invention comprise all types of chewing gums and chewing gum formulations including sugared or sugarless chewing gum known to Those skilled in the art. Typical chewing gum compositions comprise a chewing gum base, a softening agent, a bulking agent or sweetener, and a flavoring agent. Exemplary of suitable chewing gum bases are chicle, or substitutes thereof, guttakay, sorva, jelutong, synthetic polymers such as polyvinyl acetate, synthetic resins, rubbers and the like, and mixtures of the above ingredients. The proportion of the gum base used in the formulation generally varies with the type of gum base material selected and other ingredients used in making up the final gum product. The amount of gum base generally ranges from about 15% by weight to about 110% by weight, preferably from about 20% to about 30% by weight, based upon the weight of the final product. Known softening agents or plasticizers such as lecithin, glycerine, lanolin, propylene glycol and the like or mixtures thereof are incorporated into the gum base to achieve the desired consistency and texture. The amount of softener employed in the formulation typically varies from about 1% to about 5% by weight based on the weight of the final product. The flavoring agent used in the formulation may be essential oils, synthetic flavors, or mixtures of the above. Popular flavors are cinnamon, wintergreen, spearmint, peppermint, fruit flavors and licorice. Flavoring agents generally are used in amounts of about 0.75% by weight to about 1.5% by weight based on the weight of the final product. The bulking agents or additional sweeteners which can be used in preparing the chewing gum are known to those skilled in the art. Exemplary thereof are sugars such as sucrose, glucose, dextrose, fructose and mixtures thereof; artificial sweeteners such as saccharine and its salts, Acesulfam-K (the potassium salt of 3,4-dShydro-6-methyl-1,2,3-oxathiazin-4-one-2,2- dioxide), glycyrrhizin, thaumatin, stevia, and mixtures thereof; and sugar alcohols such as sorbitol, sorbitol syrup, xyiitol, mannitol and mixtures thereof. The choice of compatible ingredients and proportions of bulking agents or sweeteners to produce an acceptably sweet chewing gum are also known. The amount of bulking agent or sweetener generally ranges from about 55% by weight to about 80% by weight, based upon the weight of the final product. The chewing gum formulations are prepared in conventional manner. Typically, the gum base, softening agent, bulking agent or sweetener, and flavoring agent, are sequentially added and mixed, or blended, in a standard dough mixer equipped with sigma blades. In known processes for incorporation of aspartame into the gum, the aspartame is added last with minimal mixing. The gum is then extruded into ropes or rolled into flat sheets, cut and wrapped. Extrusion followed by rolling can also be used to produce flat sheets or ropes. Additional sweetener or flavoring agent may be applied before cutting or wrapping. Knawn dusting agents such as calcium carbonate, talc, sugar alcohols, sugar, starch, and mixtures thereof are generally applied by dusting them -onto the gum surface prior to or during one or more of the rolling, cutting, or wrapping operations. In the process of the present invention, the aspartame is applied to the surface of the sheet of gum simultaneously with or after imprinting, but preferably prior to cutting. The conventional dusting agents are preferably applied to the gum both prior to imprinting and blended with the aspartame. The present invention is further illustrated in the following examples. All percentages, parts, and proportions are by weight and all temperatures are in OF unless otherwise indicated: EXAMPLE 1 The relative amounts of the ingredients of the chewing gum composition to which the aspartame is applied are: Approximate Ingredient Weight Percent Chewing Gum Base 30 Softener (lecithin) 0.9 Sorbitol powder 43 Sorbitol solution 25 (70% solids) Flavor (peppermint) 1.1 100% The chewing gum composition is prepared-in conventional manner in a dough mixer equipped with sigma-blades, rolled into a sheet, scored into gum slabs and cut into sticks. The sticks were imprinted with a hand roller having straight circumferential projections to obtain indentations thereon. The indentations extended the length of the gum stick, were about 0.25 mm inches deep and about 0.25 mm wide. Each gum stick had 18 indentations spaced about 3 mm apart. The encapsulated asp-artame and aspartame-mannitol blend were sprinkled by hand onto the imprinted gum sticks. The gum sticks were then rolled with a smooth roller to transfer the aspartame or the blend into the indentations and to remove the excess from the raised portions of the gum stick. Samples of the gum sticks were placed in a foil-lined pouch which was then heat sealed. The gum samples were subjected to a three-week accelerated stability test at 301 relative humidity and 1050F. Aspartame content of the samples was determined by the ninhydrin method at initiation and termination of the three-week accelerated test. The accel-erated test is equivalent to a 7 to 8 month shelf life under normal storage conditions. A summary of the results of the analyses is: Sample No. Initial Aspartame and Aspartame Content After Aspartame Aspartame Content Aging, Retention, Form gm/stick W/% (%) 1. 50% Pure Powder 50% Mannitol 0.0102 0.0101 99 2. Durkee Fat encapsulated 33% aspar- 0.0087 0.0076 87 tame The sweetness stability of the aspartame sweetened gum was compared to the sweetness stability of an aspartame sweetened chewing gum having aspartame incorporated into the chewing gum composition set forth above. The aspartame used in the control was in pure powdered form. The amount of aspartame incorporated into the control was 0.25% aspartame, based upon the total weight of the aspartame sweetened gum composition. The control gum sticks were prepared as above except the aspartame was the last ingredient added to the dough mixer and mixing was continued to obtain substantial homogeneity. Samples of the gum sticks were placed and heat sealed in a foil-lined pouch as above. The gum samples were subjected to a three-week accelerated test, at 30% relative humidity and 1050F. The aspartame content of the samples was determined by the ninhydrin method at initiation and termination of the accelerated test. The results of the analyses were an aspartame content at initiation of the accelerated test of 0.22S, a final aspartame content of 0.168%, for an aspartame retention during the three-week test period of about 76S. EXAMPLE 2 Aspartame sweetened gum sticks were prepared as in Example 1, Sample 2 except cinnamon was used as the flavoring agent instead of peppermint. The results of the three-week accelerated stability test were an initial aspartame content of 0.0101 gm/stick, an aspartame content after aging of 0.0089 gm/stick, and an aspartame retention of 88S. The imprinting process of the present invention can be used to provide accurate and consistent control over the amount of and distribution of sweetening compositions which do not contain aspartame on a gum surface. For example, sorbitol, mannitol, saccharine and its salts, Acesulfam-K, and mixtures thereof can be applied into indentations in the gum surface electrostatically in amounts which provide an acceptable level of sweetness in accordance with the present invention.

Claims: What is claimed is: 1. A process for sweetening chewing gum with an L-aspartic acid sweetening derivative comprising imprinting at least a portion of the surface of the chewing gum with one or-more indentations and applying an L-aspartic acid sweetening derivative into said indentations. 2. A process as claimed in claim 1 wherein said L-aspartic acid sweetening derivative is aspartame. 3. A process as claimed in claim 2 wherein the aspartame content of the sweetened gum 18 less than 0.3S by weight, based on the weight of the aspartame sweetened chewing gum. 4. A process as claimed in claim 3 wherein the weight percent of aspartame us from 0.1X to 0.25S. 5. A process as claimed in claim 4 wherein the application of aspartame is performed electrostatically. 6. A process as claimed in claim 2 wherein substantially all of the aspartame is applied within said indentations. 7. A process as claimed in claim 2 wherein said indentations are formed and the aspartame is applied into said indentations simultaneously. 8. A process as claimed in claim 2 wherein the said indentations are formed substantially uniformly over a surface of the chewing gum. 9. A chewing gum composition having improved sweetness stability of aspartame comprising a chewing gum upon whose surface multiple indentations have been imprinted, the aspartame being held within said indentations. 10. A chewing gum composition as claimed in claim 9 wherein the easpartame content of the chewing gum composition is less than 0.3S by weight based on the weight of the composition. 11. A chewing gum composition as claimed in claim 9 wherein the aspartame content of the chewing gum composition is about 0.1% to about 0.25S by weight based on the weight of the composition. 12. A chewing gum composition as claimed in claim 11 wherein substantially all of the aspartame is held within said indentations. 13. A chewing gum composition as claimed in claim ll wherein the indentations are distributed substantially uniformly over a surface of the chewing gum piece. 14. A chewing gum composition as claimed in claim 11 wherein the indentations are at least substantially filled with aspartame. 15. A chewing gum composition as claimed in claim 14 wherein less than about 10X of the surface-of the chewing gum piece is indented. 16. A chewing gum composition as claimed in claim 14 wherein said indentations are in the shape of -one or more grooves. 17. A chewing gum composition as claimed in claim 12 wherein substantially -all of the aspartame and a dusting material are held within said indentations. 18. A chewing gum composition, as claimed in claim 17 wberein said dusting material is mannitol. 19. A process for sweetening chewing gum with aspartame comprising: a. applying at least one dusting material to the surface of the chewing gum composition to reduce its stickiness, b. forming the dusted chewing gum composition, c. removing excess dusting material from the surface of the formed chewing gum composition, d. providing one or more indentations on at least a portion of the surface of the chewing gum compositlon obtained in step (c), e. applying aspartame into said indentations, and f. removing excess aspartame from the surface of the formed chewing gum composition, the aspartame content of the sweetened gum being less than 0.3% by weight, based on the weight of the aspartame sweetened gum. 20. A process as claimed in claim 19 wherein steps (d) and (e) are performed simultaneously. 21. A process as claimed in claim 19 wherein the aspartame is applied into the indentations electrostatically. 22. A process as claimed in claim 19 wherein the aspartame is applied as a blend with at least one dusting material. 23. A process as claimed in claim 21 wherein the aspartame is applied as a blend with at least one dusting material. 24. A process as claimed in claim 22 wherein the dusting material which is blended with the aspartame is mannitol. 25. A process as claimed in claim 24 wherein excess aspartame and mannitol are removed from the surface of the chewing gum compositio by brushing the gum surface and applying a vacuum to the gum surface. 26. A process as claimed in claim 25 wherein the aspartame and mannitol blend is applied into said indentations by gravity flow onto the surface, followed by said brushing of the gum surface. 27. A process as claimed in claim 25 wherein the brushed gum surface is subsequently pressed by a roller. 28. A process as claimed in claim 21 wherein the formed chewing gum composition is negatively charged and a positively charged embossing roller is used to form said indentations and to apply the aspartame into the indentations. 29. A process as claimed in claim 19 wherein the dusted chewing gum composition of step (b) is cut into strips prior to removal of excess dusting material. 30. A process for sweetening chewing gum comprising: a. applying at least one dusting material to the surface of the chewing gum composition to reduce its stickiness, b. forming the dusted chewing gum composition, c. removing excess dusting material from the surface of the formed chewing gum composition, d. providing one or more indentations on at least a portion of the surface of the chewing gum composition obtained in step (c), and e. applying a sweetener into said indentations electro statically. 31. A process as claimed in claim 30 wherein the sweetener is mannitol, saccharine or one of its salts, sorbitol, aspartame, or mixtures thereof.

Inventors: DONNA, MARIA ROSA, PUGLIA, WAYNE JOSEPH
Applicants: NABISCO BRANDS INC.
Application year: 1984
Main classification: A23G3
IPC codes: A23L1, A23G4