Carbonated chewing gum
This application is a continuation-in-part of application Ser. No. 777,797, filed Mar. 15, 1977 now U.S. Pat. No. 4,105,161 issued Apr. 17, 1979. 
    
    
     BACKGROUND OF THE INVENTION 
     Carbonated candy is a hard candy containing carbon dioxide gas as disclosed in U.S. Pat. No. 3,012,893 which is herein incorporated by reference. Such a candy is made by the process which comprises melting crystalline sugar, contacting such sugar with gas at a pressure of 50 to 1,000 psig for a time sufficient to permit adsorption in said sugar of 0.5 to 15 ml of gas per gram of sugar, maintaining the temperature of said sugar during said adsorption above the solidification temperature of the melted sugar, and cooling said sugar under pressure to produce a solid amorphous sugar containing the gas. 
     The resultant product contains 1% to 5% water and most typically 2% to 3% water by weight of the total composition. Lower levels of moisture are not practicably obtainable because the additional heat necessary to drive off the water causes the candy melt to caramelize or burn, resulting in an off-flavor, undesirable product. Higher moisture levels result in a soft, sticky matrix which rapidly liberates the entrapped gas and is thus not storage stable. It has been found that the water activity of the product made according to the above patent is between about 0.10 to about 0.30. Additionally, the candy glass, in order to maintain storage stability, must be isolated from any source of free water and is thus packaged in a moisture-resistant container. Free water softens the candy allowing the trapped gas to escape. 
     The carbonated candy when placed in the mouth produces an entertaining but short lived popping sensation. As the candy is wetted in the mouth the candy melts and the carbon dioxide escapes. The effect in the mouth is sensational but short. 
     Conventional chewing gums are available in a variety of forms. The gum base may be any chewable substantially water insoluble base such as chicle and substitutes thereof, sorva, guttakay, jelutong, synthetic polymers such as polyvinyl acetate, synthetic resins, rubbers, mixtures of these and the like. The percentage of gum base employed in chewing gums may vary widely according to the type used and other ingredients employed and whether the final product is a &#34;stick&#34; chewing gum or a &#34;bubble&#34; gum or dragee. Minor amounts of plasticizers or softeners may also be incorporated in the gum base. 
     Flavors generally employed in the preparation of flavored chewing gums are the essential oils of synthetic flavorings used either singly or in combination with other natural and synthetic oils. Flavors such as wintergreen, spearmint, peppermint, birch, anise fruit flavors, mixtures thereof and the like may be used satisfactorily with a variety of gum bases. The amount of flavoring material used will vary depending on the type used, individual taste preferences, the gum base employed and other such considerations. 
     The sweetener or sweeteners added to complete the chewing gum composition categorize the gum as either a sugarless or a sugar gum. Sugar gum is intended to include not only sucrose but also the other sugarlike sweeteners normally employed in chewing gums such as dextrose, glucose (corn syrup), fructose and the like and mixtures thereof. Sugarless gums normally include synthetic sweetening agent such as saccharin or cyclamate or salts thereof and/or the dipeptide sweetening agents dihydrochalcones and the like or mixtures thereof combined with a sugar alcohol such as sorbitol and mannitol. Where the sugar alcohol has a sweetness intensity near sucrose, such as xylitol, then synthetic sweetener may be dispensed with. 
     The gums are conventionally prepared by mixing heated chewing gum base and sweetening agents such as sucrose as an aqueous sugar syrup or in the case of sugarless chewing gums an aqueous sugar alcohol solution plasticizers and flavor. These aqueous solutions typically contain 15% to 70% water. The resultant product contains from 1% to 5% by weight of moisture. Such moisture levels are required to render conventional gum pliable. At lower moisture the gum becomes hard and brittle. Additionally, in order to preserve the moisture content of the gum, each piece is enveloped with at least one protective wrapper. 
     The water activity of conventional chewing gums is typically about 0.35 to about 0.60. The sugar and sugar alcohols in conventional chewing gum remain crystalline in form. Thus, the moisture content of conventional gum exists essentially as free water, being absorbed on the surface of sugar or sugar alcohol crystals. This is contrasted with the moisture existing in amorphous carbonated candy which is bound within the structure and has a substantially lower water activity. 
     When conventional chewing gum containing 1-5% water contacts or is packaged with carbonated candy, the water migrates from the gum to the candy and the candy becomes sticky and loses its characteristic pop and sizzle while at the same time the gum becomes hard and stale. 
     U.S. Pat. No. 3,262,784 (Fleer) discloses a low moisture chewing gum. Such a gum is a crumbly friable material and resembles sand or powdered sugar at room temperature. The crystalline sugar component has a low moisture content well below 1%. The gum base is dry. While the Fleer patent discloses gum base proportions to 40%, the bubble gum is usually between abot 5% to about 27% for sugar alcohol gums and 6% to 25% when sucrose is used. 
     SUMMARY OF THE INVENTION 
     This invention provides compressed, shaped confection comprised of at least two components with each component having a water activity of about 0.10 to about 0.30 which is capable of surviving long periods of storage when packaged in a moisture-resistant material. These components are gum and carbonated candy. The gum portion is preferably a sugar or sugarless bubble gum with a gum base content of at least 28% by weight of the total gum composition whereby the gum is pliable at room temperature. The carbonated candy portion of the confection comprises amorphous candy glass having a moisture content of 11/2 to 5% water which has contained therein 0.05 to 15 milliliters of a gas, preferably carbon dioxide in each gram of composition. The water activity of the gum portion is substantially identical or becomes substantially identical on storage to the carbonated candy portion to minimize moisture transfer between each component. Products can be formulated that are sugar based, sugarless using sugar alcohols in both gum and candy or combinations of sugar gum and sugar alcohol based candy or sugar alcohol gum and sugar based candy. Sucrose based gum and candy are preferred, but good sugarless products using a sugar alcohol gum and candy may be formulated. 
     DETAILED DESCRIPTION OF THE INVENTION 
     In the preferred embodiment of the instant invention, the gum portion of the confection is a sugar-containing bubble gum. It will be readily apparent to those skilled in the art that a variety of gum types are readily adaptable to the practice of this invention. Commercially available conventional bubble gums generally have a base content of between about 10% to about 15% and in some cases as high as 18%. Those skilled in the art have heretofore considered the above amounts as the limits of the percentage of gum base in a bubble gum product. 
     Conventional bubble gum is normally formulated to have a final moisture content of 1% to 5%. Said moisture allows the gum to be pliable at room temperature. However, to insure that this moisture stays within the gum, the product is generally protected by several layers of packaging material. It is this moisture content which makes conventional gums incompatible with carbonated candy. This is because the sugar or sugar alcohols in the gums are crystalline in structure so that the water content therein or adsorbed therein, exists essentially as free water. Therefore, the water activity of conventional gums is typically above 0.3 to about 0.5. Any substantial reduction in the moisture content of the conventional gum to attempt to make it compatible with carbonated candy, said candy having a water activity of from about 0.10 to about 0.30, results in a dry or stale gum. 
     Attempts to reduce the water activity of conventional gum by the addition of water activity depressants have not met with success. A typical depressant is glycerol. However, the amount of glycerol necessary to reduce 2.5% moisture gum having a water activity of 0.56 to a water activity value of 0.2 would be an amount of glycerol greater than 50% by weight of the total gum composition. Such an amount of glycerol would render the gum a liquid and therefore be not acceptable. Thus, the instant invention, by using amounts of gum base higher than ordinarily employed by the prior art, allows the formulation of chewing gums which have a water activity identical to carbonated candy and still retain the desirable characteristics of cohesive pliability at room temperature. 
     The gum component is produced by combining component ingredients in a mixing vessel at temperatures between about 50° C. to about 70° C. and preferably between about 60° C. to about 65° C. When the ingredients are completely mixed, the warm gum is preferably next extruded into strands with diameters between 1/32 inch and 1/2 inch and preferably between 1/16 inch and 1/4 inch in diameter and most preferably 3/16 inch diameter. The strands are then cooled and treated to provide fragments. Depending on the particle size desired, the resultant pieces are passed through various sieves. The preferable particle sizes utilized pass through 4 mesh and are retained on 20 mesh (U.S. Standard Sieve). The pieces are then allowed to equilibrate to room temperature. Any moisture present during cooling can be removed by conventional means. 
     Conventional gums include water in their formulation obtained typically from corn syrup or sorbitol solution in amounts of 1% to 5% by weight of the total gum composition. According to the instant invention, no water is added during the formulation or blending of the gum. Moisture content of the instant gum is less than 0.5% and typically less than 0.2% when made of crystalline sugar or crystalline sugar alcohols. When amorphous sugar, sugar alcohols and mixtures thereof are employed, their moisture content may be from about 1% to about 5%. In both cases the water activity of the resulting gum is between about 0.10 to about 0.30 and typically between about 0.15 to about 0.25. Preferably the difference between the water activity of the first component and the second component will be no greater than 0.05. Desirably the water activity of the gum component is lower than that of the carbonated candy component. 
     The carbonated candy component of the instant confection is conventionally produced according to the process of U.S. Pat. No. 3,012,893. In the preferred embodiment of this invention, the amorphous carbonated candy is produced such that it is substantially identical or substantially the same in appearance to the gum pieces. Thus, sucrose based gum having a particle size that passes through 4 and is retained on 20 mesh (U.S. Standard Sieve) is combined with sucrose based amorphous carbonated candy whose particle size is controlled to also pass through 4 and be retained on 20 mesh. Both the gum and the candy may have the same color level and flavor. The moisture content of the candy is typically between 2.0% and 4.0%. Preferably the moisture content is between 2.8% and 3.3% by weight of the carbonated candy composition. At moisture levels above 4.0% of the candy composition becomes sticky and the entrapped gas escapes. 
     The candy and gum particles are combined usually by mere physical admixing and are then compressed into the desired geometrical shape employing a suitable mold. In practice, the compression step can be accomplished by using any suitable press, such as a tablet press, which can be manually or automatically operated. Thus, the gum and candy particles are thoroughly mixed to achieve reasonable uniformity and are charged into the die of the press in predetermined amount and the charge is then compressed into the die form, preferably employing the minimum pressure which will permit the desired agglomeration of the respective particles. The agglomeration is apparently the result of the adherence of the respective particles of gum and candy, at least partially, with the gum acting as a binder, in effect, for the candy particles and providing the structural integrity of the resulting compressed, shaped confection. 
     In the preparation of the compressed, shaped confections of this invention, the compression must be carefully regulated to avoid excessively high pressures which will tend to crush the carbonated candy and cause loss of the entrapped gas with consequent loss of the pop and/or sizzle effect on exposure to moisture. For most purposes, pressures on the order of from about 100 to about 150 pounds per square inch will suffice and usually from about 125 to about 135 psi is preferred. 
     The particle size of the gum and candy also plays a role in determining the nature of the compressed end product. Where the candy particle size is too small, the particles tend to be crushed even where moderate pressures are employed. For best results, the candy particles should pass through 4 mesh and be retained on 20 mesh. Conveniently, the gum particle size can be the same as that of the candy particles, permitting easy mixing. The preferred particles are those which pass through 8 mesh and are retained on 20 mesh. Since these particle sizes give the best result from the viewpoint of sizzling of the product on exposure to moisture, e.g., when the gum product is being chewed. 
     The present invention is particularly advantageous in that it permits the use of gum fines which otherwise have no value, except for recycle where the gum base permits. In the present new products, the gum particles employed can be those which pass through 20-100 mesh and such particles are particularly valuable in forming compressed products with carbonated candy of between 4 mesh and 20 mesh size, i.e., between about 800 and 5,000 microns in diameter. 
     The amounts of each component that can be employed in the present new products can be varied broadly but for the most part should be restricted to a ratio of gum to candy ranging from about 3:1 to about 1:3, with the optimum ratio being 1:1. 
     The shape of the compressed confection can be any geometric shape and will be dictated by the die employed in the compression step. Accordingly, there can be produced discs, oval discs, conical discs, squares, rectangles and the like. 
     The resulting compressed confection may tend to flake at the surface, especially in areas of high concentration of the carbonated candy. To minimize this effect, the products can be sprayed with non-aqueous coatings of materials such as Klucell, edible shellacs, carboxymethylcellulose and related edible cellulose derivatives, gelatin, methocel, ethocel, hydroxyalkylcellulose and the like. 
     The products of this invention show a substantially lower sensitivity to water than does the mere mixture of particulate carbonated candy and gum which permits more latitude in selection of packaging than does the latter product. These products provide a nice chew with pleasant mouth feel, they are relatively soft and easy to chew, presumably because of the presence of air pockets in the compressed product structure as well as the carbon dioxide pockets in the carbonated candy structure. There is less of a tendency to deplete the sizzling effect at the moment of exposure to moisture as evidenced by the longer sizzling effect experienced with the compressed confection in comparison to the combined, but uncompressed, particulate candy and gum. 
     As is understood by those skilled in the art, the exact methods of fabricating compressed confections in accordance with the present invention will depend to a considerable extent on the properties and effects desired in the final product. Accordingly, the particle size of the components, as well as relative amounts thereof, can be varied along with the pressure employed in fabrication to attain certain properties and these variations of processing are readily determinable by routine experimentation within the skill of the art. 
    
    
     The following examples further illustrate the invention. 
     EXAMPLE 1 
     I. Preparation of Bubble Gum with Crystalline Sugar 
     A. Formula 
     
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1. Bubble gum base     600      g                                         
2. Crystalline Sucrose 6X                                                 
                       1372                                               
3. Lecithin            4                                                  
4. Vegetable Oil       2                                                  
5. Bubble Gum Flavor   20                                                 
6. Color               2.25                                               
TOTAL                  2000.25  g                                         
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     B. Mixing Procedure 
     The gum is prepared and mixed in a Baker Perkins type J Universal mixer size No. 4 with a working capacity of 0.7 gallons and a Sigma mixing blade. The mixer is provided with a steam jacket to maintain a desired temperature. First the temperature of the apparatus is brought to 63° C. and the gum base is inserted along with 10% of the sucrose and all of the color. The mixing is then commenced and after one minute the lecithin is added. After two minutes 231/3% of the sucrose is added. After four minutes 331/3% of the sucrose is added. After four minutes and 30 seconds the bubble gum flavor is added. After six minutes 33% of the sucrose is added. After seven minutes the vegetable oil is added. Mixing is allowed to continue for another three minutes during which time the temperature is reduced approximately 10° C. After a total of ten minutes mixing, the gum is ready for extrusion. 
     The warm gum is extruded into 3/16-inch diameter strands and cooled quickly to dry ice temperature (-78° C.). The strands are fractured by hammering, yielding pieces which are sieved into the desired size fractions. The sieved pieces are then warmed to room temperature in a vacuum dessicator in order to evaporate any moisture which condensed on them during the fracturing process. After about one hour, the bubble gum pieces are ready to be compressed with the carbonated candy. The water activity of this gum portion is 0.21. 
     II. Preparation of Carbonated Candy 
     A. Formula of Carbonated Candy (final product) 
     
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1. Sucrose             1225.190 -2. Lactose 695.06                        
3. Water               60.00                                              
4. Carbon Dioxide      14.68                                              
5. Color               0.274                                              
6. Bubble Gum Flavor   4.896                                              
TOTAL                  2000.00 g                                          
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     Sucrose and lactose are mixed with water (500 g) to form a slurry. The slurry is heated rapidly to 320° F. (160° C.) to remove 97% of the water and transferred to a pre-heated autoclave where the molten candy mass is injected with flavor, color, and carbon dioxide by rapid (600 rpm) stirring to disperse the gas bubbles. The gassified candy melt is cooled quickly to room temperature. The pressure is reduced to atmospheric, and the carbonated candy, which has been fractured by the pressure reduction, is sieved through a four-sieve and onto a 20-sieve (U.S. Standard Sieve). The candy is then evaluated for carbonation quality and color; whereupon, it is ready to be compressed with the bubble gum. The water activity of this carbonated candy portion is 0.21. 
     III. Compression Procedure 
     The carbonated candy product sieve fraction which passed through 4 mesh and was retained on 20 mesh was mixed with an equal weight (4.2 g) of the gum composition of the same particle size range (-4+20) and was charged to the tablet compressor. The charge was compressed to a disc at 130 psi and retained its structural integrity on being removed from the die. The disc was 1 inch in diameter and approximately 1/2 inch thickness. 
     EXAMPLE 2 
     The procedure of Example 1 is repeated using varying weight ratios of gum to carbonated candy. Thus, 4.2 g of the gum base was compressed with 1.4 g; 2.8 g; 4.2 g and 12.6 g of carbonated candy. With 1.4 g and 2.8 g levels of candy the extent of sizzling was less than obtained with 4.2 g which gave best results. The 12.6 g level of candy gave a product which was difficult to compress because of the resulting size of the tablet.