Abstract:
The invention provides a process for producing a rawhide chew toy, comprising: combining a marinade with rawhide; applying vacuum pressure to the combined marinade and rawhide; releasing the vacuum pressure; and allowing the formed rawhide to dry under moderate temperature. In one embodiment, the combined marinade and rawhide are tumbled during the step of applying vacuum pressure. In additional embodiments of the invention, nutrients, such as, vitamins, minerals, dental additives, or herbal remedies, may be added to the marinade.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a chew toy for animals. Specifically, the invention relates to a process for making rawhide chew toys. 
     BACKGROUND OF THE INVENTION 
     Conventional rawhide chew toys come in various shapes and sizes, for example: bones, rolls, donuts, pretzels, sticks, chips, munchie, and ground-and-pressed products. A process for making conventional rawhide chew toys is described, for example, in U.S. Pat. No. 2,988,045 issued to Fisher on Jun. 13, 1961. As described by Fisher, conventional rawhide chew toys are made from processed animal skins. The animal skins are de-haired and cleaned, leaving “wet rawhide.” This wet rawhide may be formed into shapes, if desired, and then dried, upon which the chew toy becomes hard and bone-like. 
     Rawhide chew toy manufacturers have traditionally applied various flavors and coatings topically to dried rawhide to attract the animal to the rawhide chew toy. Coatings or bastings are applied to the surface of the dried rawhide by spraying a solution on the dried rawhide or by dipping the dried rawhide in the solution. Such coatings are described, for example, in U.S. Pat. No. 5,673,653 issued to Sherrill on Oct. 7, 1997 (see Col. 1, lines 55-59). 
     A problem with these conventional rawhide chew toys is that after the coating is licked off the rawhide chew toy, there is less incentive for the animal to continue chewing and the animal frequently loses interest in the rawhide chew toy. As a result, the animal owner may discard the chew toy before it is completely chewed and buy a new chew toy that still has the flavoring applied to the surface of the dried rawhide. In addition, coatings applied to the surface of the dried rawhide are easily rubbed off causing stains on carpet, etc. Further, any nutrients added to the solution and applied to the surface of the dried rawhide will not remain in the rawhide during the chewing process. 
     As a result of these and other drawbacks to the prior art, there is a need in the industry for an improved rawhide chew toy that will retain flavoring during various phases of being chewed, provide a vehicle for delivering nutrients to animals, and is less likely to create stains upon being chewed by an animal. 
     SUMMARY OF THE INVENTION 
     An object of the invention is to provide a process for producing a rawhide chew toy, comprising combining a marinade with wet rawhide; applying vacuum pressure to the combined marinade and wet rawhide; releasing the vacuum pressure; and drying the marinated rawhide. 
     In a further aspect of the invention, the vacuum pressure applied to the combined marinade and wet rawhide is between 5 and 25 in. Hg. 
     In a further aspect of the invention, the combined marinade and wet rawhide are tumbled during the step of applying vacuum pressure. 
     In another aspect of the invention, nutrients, such as, vitamins, minerals, dental additives, or herbal remedies may be added to the marinade. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     FIG. 1 is a flowchart illustrating the steps performed to produce a rawhide animal chew in accordance with an aspect of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1 is a flowchart illustrating the steps performed to produce a rawhide animal chew in accordance with an aspect of the present invention. Rawhide is comprised of connective collagen fibers. It has been discovered that when wet rawhide is subjected to vacuum pressure (air pressure below atmosphere pressure also referred to herein as negative atmospheric pressure) the fibers swell to between approximately two to three times their normal size. This swelling action opens the fibers, which can then receive a solution of marinade throughout. 
     The marinade and wet rawhide are combined in a drum at step  100 . The absorption of the marinade into the fibers is aided by applying vacuum pressure at step  105  to the combined marinade and wet rawhide. In other embodiments, the absorption of the marinade is aided by tumbling the wet rawhide together with the marinade at step  110 . This tumbling action forces the marinade throughout the fibers. In further embodiments, the vacuum pressure can be combined with a tumbling action. When tumbling is complete and the vacuum pressure is released at step  115 , the marinated rawhide contracts to approximately its original size and is believed to trap the marinade throughout the rawhide. 
     In one embodiment the chew toy is created by using wet rawhide that is cut into strips. At step  120 , the wet strips of marinated rawhide are formed into various shapes and sizes as listed above and allowed to dry and harden at step  125 . In another embodiment, the wet strips of marinated rawhide are dried at step  125  by placing them into a drying oven until a moisture level below approximately 12% is achieved. A moisture-content of less than or equal to approximately 12% is known in the art to prevent rotting, mold, or other spoilage of the chew toy. 
     Various additives may be mixed with the marinade, including the following examples: 
     
       
         
               
               
               
               
             
               
               
             
               
               
               
               
             
           
               
                   
               
             
             
               
                 1) 
                 Vitamins 
                   
                   
               
               
                   
                 Vitamin A 
                 Vitamin D 
                 Vitamin E 
               
               
                   
                 Vitamin K 
                 Thiamin (B1) 
                 Riboflavin (B2) 
               
               
                   
                 Niacin 
                 Pyridoxine (B6) 
                 Panthothenic Acid 
               
               
                   
                 Biotin 
                 Folic Acid 
                 Vitamin B12 
               
               
                   
                 Choline 
                 Vitamin C (Ascorbic Acid) 
               
               
                 2) 
                 Minerals 
               
               
                   
                 Calcium 
                 Phosphorus 
                 Zinc 
               
               
                   
                 Magnesium 
                 Manganese 
                 Iron 
               
               
                   
                 Copper 
                 Sodium 
                 Potassium 
               
               
                   
                 Chloride 
                 Iodine 
                 Sulphur 
               
               
                 3) 
                 Dental additives 
               
             
          
           
               
                   
                 Glucosoxidase Lactoperoxidase (for Tartar build up) 
               
               
                   
                 Copper Chlorophyllin (for bad breath control) 
               
             
          
           
               
                 4) 
                 Herbal Remedies 
                   
                   
               
               
                   
                 Echinacea 
                 Guarana 
                 Chamomile 
               
               
                   
                 Gingko Biloba 
                 St. John&#39;s Wort 
                 Kava Kava 
               
               
                   
                 Valerian Root 
                 Aloe Vera 
                 Goldenseal 
               
               
                   
                 Fenugreek 
               
               
                 5) 
                 Spices/flavors 
               
               
                   
                 Garlic 
                 Capcicum sp. Allspice 
               
               
                   
                 Clove 
                 Kelp 
               
               
                 6) 
                 Oils 
               
               
                   
                 Lecithin 
                 Primrose Oil 
                 Tea Tree Oil 
               
               
                   
                 Flaxseed Oil 
                 Borage Oil 
                 Soybean Oil 
               
               
                   
                 Sunflower Oil 
                 Fish Oils 
                 Peppermint Oil 
               
               
                   
               
             
          
         
       
     
     These additives attract the animal as well as aid the health and well-being of the animal. The marinated rawhide has the flavor and/or additives impregnated throughout the rawhide and the flavor will last as the animal chews the marinated rawhide chew toy. 
     One embodiment of the process includes the following steps. At step  100 , one or more cut, wet rawhide strips are placed into a sealable container, such as a drum of a vacuum tumbler, together with a formulated marinade solution. The formulation for the marinade used in one embodiment is described below under the Examples. At step  105 , the drum is sealed and negative atmospheric pressure is applied for a specified time. After expiration of the specified time, some commercial vacuum tumblers then require that a vacuum tube be disconnected. In a preferred embodiment, in steps  105  and  110 , a timer is set to tumble the drum and apply a vacuum for a specified time, as provided in the Examples below. After expiration of the specified tumble and vacuum time, the valve is opened to equalize pressure in the drum at step  115 . 
     To remove the marinated rawhide strips, the drum can be agitated to dump the marinated rawhide into a basket under the drum. Any excess marinade can be re-used for a later batch. Upon removal of the marinated rawhide strips from the drum, the marinated rawhide strips are allowed to drain, for example, by setting them on a rack for a specified amount of time. Then the marinated rawhide strips may be formed into desired shapes and allowed to dry at step  125 , for example by baking, until less than approximately 12% moisture is retained by the rawhide. 
     The following is one Example of a formulation for a marinade solution: 
     
       
         
               
             
               
               
               
             
               
               
               
               
             
               
             
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
               
             
             
               
                 TOTAL MARINADE SOLUTION 
               
             
          
           
               
                   
                 INGREDIENT 
                 QUANTITY 
               
               
                   
                   
               
             
          
           
               
                   
                 Vitamin Premix 
                 250 
                 gm 
               
               
                   
                 M100 (Maltodextrin) 
                 2 
                 lbs 
               
               
                   
                 Citric Acid 
                 10 
                 gm 
               
               
                   
                 Purified Water 
                 83.30 
                 lbs 
               
               
                   
                 TOTAL LIQUID 
                 85.87 
                 lbs 
               
               
                   
                   
               
             
          
           
               
                 VITAMIN PREMIX COMPOSITION: 
               
             
          
           
               
                   
                   
                   
                 TOTAL 
               
               
                 VITAMIN 
                 CONCENTRATION 
                 AMOUNT 
                 PROVIDED 
               
               
                   
               
             
          
           
               
                 A 
                 650,000 
                 IU/gm 
                 12.4 
                 gm 
                 8,060,000 
                 IU 
               
               
                 D 
                 541,000 
                 IU/gm 
                 1.0 
                 gm 
                 541,000 
                 IU 
               
               
                 E 
                 500 
                 IU/gm 
                 6.0 
                 gm 
                 3,000 
                 IU 
               
               
                 Biotin 
                 98% 
                 purity 
                 0.016 
                 gm 
                 0.01568 
                 gm 
               
               
                 Sodium 
               
               
                 Bicarbonate 
                 0 
                   
                 230.5840 
                 gm 
               
               
                 TOTAL: 
                   
                   
                 250 
                 gm 
               
               
                   
               
             
          
         
       
     
     While Applicant used the formulation described above in one embodiment, the invention claimed herein is not limited by this particular formulation. 
     Using the marinade formulation of the embodiment described above, strips of wet rawhide were combined with specified quantities of marinade solution and placed into a commercial vacuum tumbler, specifically a Hollymatic model HVTS200. Hollymatic Corporation, 600 E. Plainfield Road, Countryside, Ill. 60525, manufactures several modes of vacuum tumblers for processing foods. Also see, for example, U.S. Pat. Nos. 5,158,794, 5,004,618 and 5,084,286. Other machines for applying vacuum pressure to the combination of wet rawhide and marinade are believed to be interchangeable with that described herein. 
     Three experimental runs of various ratios of wet rawhide to marinade were conducted to determine the absorption of marinade into the rawhide. For the Examples below, the vacuum was set for 22 in. Hg vac. and the combination was tumbled at 10 rotations per minute (rpm). The duration and ratios are provided in the table below. In all tests, substantially all the marinade was absorbed by the rawhide strips following the specified run time. 
     EXAMPLES 
     
       
         
               
               
               
               
             
           
               
                   
               
               
                 TEST # 
                 WET RAWHIDE 
                 AMT. MARINADE 
                 TUMBLE TIME 
               
               
                   
               
             
             
               
                 1 
                 25 lbs. 
                 8 lbs. 
                 10 min. 
               
               
                 2 
                 25 lbs. 
                 8 lbs. 
                 10 min. 
               
               
                 3 
                 25 lbs. 
                 7 lbs. 
                  5 min. 
               
               
                   
               
             
          
         
       
     
     It is believed that the amount of vacuum pressure, the tumbling speed, and the time that the wet rawhide is mixed with the marinade each contribute to the absorption of the marinade into the wet rawhide. For example, approximately the same ratio of marinade to rawhide may be absorbed by the rawhide under less vacuum pressure, but it may take longer for the rawhide to fully absorb the marinade. It is believed that any amount of vacuum pressure will affect the inventive process, although, in a preferred embodiment, a negative pressure between 5-25 in. Hg vac. was used. 
     After removal of the rawhide strips from the drum, the strips were set on racks to allow excess marinade to drain. After 5 hours, 10% of the absorbed marinade had drained from the rawhide. Then the rawhide strips were hand rolled into bone shapes and placed under moderate heat of approximately 135 degrees F. (or 52.7 degrees C.) for 4 days (or 96 hours) to dry. As stated above, in a preferred embodiment, the moisture content is lowered to less than approximately 12%. 
     Laboratory results indicated that vitamins contained in the premix were retained in the rawhide at the levels provided in the chart below even after the rawhide was dried using the above drying conditions. The concentration represent average units per kilogram of dried rawhide tested. The selection of the vitamins used in this trial was based on the ease of analysis, as well as the nutritional importance for the animal, but none of the nutrients are to limit the scope of the invention as set forth in the claims. 
     
       
         
               
             
               
               
             
               
               
               
               
             
               
               
               
               
               
               
               
             
           
               
                   
               
               
                 Concentration Levels Found in Dried Rawhide 
               
             
          
           
               
                   
                 Test No. 
               
             
          
           
               
                 Nutrient 
                 1 
                 2 
                 3 
               
               
                   
               
             
          
           
               
                 Vitamin 
                 187,500 
                 IU/kg avg 
                 150,800 
                 IU/kg avg 
                 82,180 
                 IU/kg avg 
               
               
                 A 
               
               
                 Vitamin 
                 1,604 
                 IU/kg avg 
                 2,974 
                 IU/kg avg 
                 4,989 
                 IU/kg avg 
               
               
                 D 3   
               
               
                 Vitamin 
                 38.8 
                 IU/kg avg 
                 36.2 
                 IU/kg avg 
                 73.0 
                 IU/kg avg 
               
               
                 B 
               
               
                 Biotin 
                 0.296 
                 ppm 
                 0.321 
                 ppm 
                 0.260 
                 ppm 
               
               
                   
               
             
          
         
       
     
     In conclusion, it will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present example and embodiment, therefore, is to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein. Modifications in the selection, design, and arrangement of the various components and steps discussed herein may be made without departing from the scope of the invention as set forth in the appended claims.