As is known in the art, chewing gum compositions typically comprise a water soluble bulk portion, a water insoluble chewing gum base portion and typically water insoluble flavoring agents. The water soluble portion dissipates with a portion of the flavoring agent over a period of time during chewing. The gum base portion is retained in the mouth throughout the chewing process.
The gum base includes a number of ingredients, some of which are subject to deterioration through oxidation during storage. The insoluble gum base generally comprises elastomers, elastomer plasticizers, waxes, fats, oils, softeners, emulsifiers, fillers, texturizers and miscellaneous ingredients such as antioxidants, preservatives, colorants and whiteners. Ingredients having a double bond between carbon atoms, including fats, oils, some elastomers and elastomer plasticizers, are susceptible to oxidation. The gum base constitutes between 5-95% by weight of the chewing gum composition, more typically 10-50% by weight of the chewing gum, and most commonly 15-35% by weight of the chewing gum.
Commonly used natural or artificial antioxidants/preservatives include beta-carotenes, acidulants (e.g. Vitamin C), propyl gallate, butylated hydroxyanisole (BHA), and butylated hydroxytoluene (BHT). The most notable and commonly used of these include synthetic antioxidants BHA and BHT.
Tocopherols are naturally occurring compounds which are known to have antioxidant properties. The most common tocopherol, alpha-tocopherol, is also known as vitamin E. The other common homologs are beta, gamma and delta tocopherols. Natural tocopherols are usually derived from vegetable oils, especially soybean oil. Tocopherols can also be found in many spices, fruits, nuts, seeds and other plant sources.
Tocopherols have previously been used successfully as stabilizers for some chewing gum ingredients, such as styrene butadiene rubber, but only when added in combination with certain synthetic stabilizers. U.S. Pat. No. 4,489,099 issued to Shaheen et al. discloses the use of vitamin E tocopherol in combination with dilauryl thiodipropionate (DLTDP), as a stabilizer for a styrene butadiene rubber. The stabilizer system may be combined with the rubber using a variety of techniques, including emulsification of the stabilizer followed by addition to styrene butadiene rubber latex, and coagulation of the latex.
U.S. Pat. No. 2,333,656 discloses a synergystic effect between tocopherol and quinones, when used as antioxidant for fats and oils. Japan Patent Disclosure 88-31442 discloses a deodorizing agent which can be used in chewing gum, which can contain a mixture of methyl hesperidin and delta tocopherol.
U.S. Pat. No. 4,694,090 discloses that vitamin E (alpha tocopherol) is known as a highly safe antioxidant, but states that vitamin E is likely to become oxidized and discolored. Until now, tocopherols have not been sufficiently effective when used as chewing gum antioxidants, without other antioxidants also being present.