chewing gum chewing gum chewing gum is a soft, cohesive substance designed to be chewed without being swallowed. modern chewing gum is composed of gum base, sweeteners, softeners/plasticizers, flavors, colors, and, typically, a hard or powdered polyol coating. its texture is reminiscent of rubber because of the physical-chemical properties of its polymer, plasticizer, and resin components, which contribute to its elastic-plastic, sticky, chewy characteristics. chewing guman unwrapped stick of chewing gumtypeconfectionerymain ingredientsgum base, sweeteners, plasticizers, flavors, colors, polyols media: chewing gum history sticks of fruit stripe chewing gum traditional extraction of chicle from chicozapote tree (achras zapota) in quintana roo, mexico. this way of extracting by making zigzag incisions has been known since the ancient mayan civilization, who called it sicté. the cultural tradition of chewing gum seems to have developed through a convergent evolution process, as traces of this habit have arisen separately in many early civilizations. each early precursor to chewing gum was derived from natural growths local to the region and was chewed purely out of the instinctual desire to masticate. early chewers did not necessarily desire to derive nutritional benefits from their chewable substances but at times sought taste stimuli and teeth cleaning or breath-freshening capabilities. chewing gum in many forms has existed since the neolithic period. 5,000-year-old chewing gum made from birch bark tar, with tooth imprints, has been found in kierikki in finland. the tar from which the gums were made is believed to have antiseptic properties and other medicinal benefits. it is chemically similar to petroleum tar and is in this way different from most other early gum. the mayans and aztecs were the first to exploit the positive properties of gum; they used chicle, a natural tree gum, as a base for making a gum-like substance and to stick objects together in everyday use. forms of chewing gum were also chewed in ancient greece. the ancient greeks chewed mastic gum, made from the resin of the mastic tree. mastic gum, like birch bark tar, has antiseptic properties and is believed to have been used to maintain oral health. both chicle and mastic are tree resins. many other cultures have chewed gum-like substances made from plants, grasses, and resins. variations of early chewing gum worldwide ancient civilization chewing gum precursor ancient greece mastic tree bark ancient maya chicle chinese ginseng plant roots inuit blubber native americans sugar pine and spruce sap south americans coca leaves south asia (india) betel nuts tropical west africa kola nuts united states (early settlers) tobacco leaves although chewing gum can be traced back to civilizations worldwide, the modernization and commercialization of this product mainly took place in the united states. the american indians chewed resin made from the sap of spruce trees. the new england settlers picked up this practice, and in 1848, john b. curtis developed and sold the first commercial chewing gum called the state of maine pure spruce gum. in this way, the industrializing west, having forgotten about tree gums, rediscovered chewing gum through the first americans. around 1850 a gum made from paraffin wax, a petroleum product, was developed and soon exceeded the spruce gum in popularity. to sweeten these early gums, the chewer would often make use of a plate of powdered sugar, which they would repeatedly dip the gum in to maintain sweetness. william semple filed an early patent on chewing gum, patent number 98,304, on 28 december 1869. an image of a colgan's taffy tolu chewing gum chromolithograph advertisement, circa 1910the first flavored chewing gum was created in the 1860s by john colgan, a louisville, kentucky, pharmacist. colgan mixed with powdered sugar the aromatic flavoring tolu, a powder obtained from an extract of the balsam tree (myroxylon), creating small sticks of flavored chewing gum he named "taffy tolu". colgan also led the way in the manufacturing and packaging of chicle-based chewing gum, derived from manilkara chicle, a tropical evergreen tree. he licensed a patent for automatically cutting chips of chewing gum from larger sticks: us 966,160 "chewing gum chip forming machine" 2 august 1910 and a patent for automatically cutting wrappers for sticks of chewing gum: us 913,352 "web-cutting attachment for wrapping-machines" 23 february 1909 from louisville, kentucky, inventor james henry brady, an employee of the colgan gum company. modern chewing gum was first developed in the 1860s when chicle was brought from mexico by the former president, general antonio lopez de santa anna, to new york, where he gave it to thomas adams for use as a rubber substitute. chicle did not succeed as a replacement for rubber, but as a gum cut into strips and marketed as adams new york chewing gum in 1871. black jack (1884), which is flavored with licorice, chiclets (1899), and wrigley's spearmint gum were early popular gums that quickly dominated the market and are all still around today. chewing gum gained worldwide popularity through american gis in wwii, who were supplied chewing gum as a ration and traded it with locals. synthetic gums were first introduced to the u.s. after chicle no longer satisfied the needs of making good chewing gum. by the 1960s, us manufacturers had switched to butadiene-based synthetic rubber, as it was cheaper to manufacture. in the united states, chewing gum experienced a decline in popularity in the early 21st century, as it lost its association with counterculture and teenage rebelliousness. others blamed smartphones reducing impulse purchases at the checkout. ingredient composition gum base composition is considered proprietary information known by select individuals within each gum-manufacturing company. information about the other components of chewing gum are more accessible to the public and they are listed in table 2. table 2: common ingredients in the formulation of modern chewing gum ingredient percent (by weight) composition functionality common examples gum base 25–35% although the formulation of gum bases is considered proprietary information for industry competitors, three main components make up all gum bases: resin, wax, and elastomer. resin (ex. terpene) is the main chewable portion. wax softens the gum. elastomers add flexibility. the molecular composition of gum base is very similar to that of plastics and rubbers. natural or synthetic ingredients (see table 3) sweeteners sugar alcohols: 40–50% artificial sweeteners: 0.05–0.5% bulk polyol sweeteners are responsible for initial sweetness, whereas intensive sweeteners are intended for prolonging the sweetness effect. intensive sweeteners are often encapsulated to delay the release of flavor. bulk polyol sweeteners: sugar, dextrose, glucose or corn syrup, erythritol, isomalt, xylitol, maltitol, mannitol, sorbitol, lactitol intensive sweeteners: aspartame, acesulfame-k, saccharine, sucralose, neohesperidine, dihydrichalcone glycerine 2–15% to maintain moistness softener/plasticizer 1–2% to soften gum by increasing flexibility and reducing brittleness by altering the glass transition temperature. quantities of this additive are altered to balance processability and packaging speed. lecithin, hydrogenated vegetable oils, glycerol ester, lanolin, methyl ester, pentaerythritol ester, rice bran wax, stearic acid, sodium and potassium stearates flavors 1.5–3.0% for taste and sensory appeal. flavor components in gum exist in liquid, powder or micro-encapsulated forms. liquid flavor incorporations are either water-soluble, oil-soluble, or water-dispersible emulsions. the oil-soluble flavors remain in the gum longer, resulting in longer lasting flavor sensations, because the gum base is hydrophobic and attracted to oil-based components. natural or synthetic peppermint and spearmint are the most popular flavors. food acids are implemented to provide a sour flavor (i.e. citric, tartaric, malic, lactic, adipic, and fumaric acids). colors variable for visual appeal natural or synthetic polyol coating variable pellet gum's characteristic hard outer shell is due to a polyol coating. polyols can also be implemented as a water absorbent powder dusting to maintain the quality and extend the shelf life of the product. these humectants bind water by establishing many hydrogen bonds with water molecules. sorbitol maltitol/isomalt mannitol starch gum base gum base is made of polymers, plasticizers, and resins. polymers, including elastomers, are responsible for the stretchy and sticky nature of chewing gum. plasticizers improve flexibility and reduce brittleness, contributing to the plastic and elastic nature of gum. the interactions of plasticizers within gum base are governed by solubility parameters, molecular weight, and chemical structure. resins compose the hydrophobic portion of the gum base, responsible for its chewiness. although the exact ingredients and proportions used in each brand's gum base are trade secrets within the gum industry, table 3 lists all of the natural and synthetic gum base components approved for use in the united states, demonstrating some examples of key gum base components. table 3: gum base ingredients approved for use by the u.s. food and drug administration (2016) natural ingredients synthetic ingredients sapotaceae chicle chiquibul crown gum gutta hang kang massaranduba balata massaranduba chocolate nispero rosidinha venezuelan chicle butadiene-styrene rubber isobutylene-isoprene copolymer (butyl rubber) paraffin (via the fischer–tropsch process) petroleum wax petroleum wax synthetic polyethylene polyisobutylene polyvinyl acetate apocynaceae jelutong leche caspi (sorva) pendare perillo moraceae leche de vaca niger gutta tunu (tuno) euphorbiaceae chilte natural rubber manufacturing process first, gum base is previously prepared through a melting and straining or filtering process. the formulation for gum base is proprietary information known to few individuals within each gum-producing company. next, other ingredients such as nutritive and non-nutritive sweeteners and flavors are added to the gum base until the warm mixture thickens like dough. the gum base mixture is heated during this mixing process to increase the entropy of the polymers to achieve a more uniform dispersion of ingredients. then, extrusion technology is implemented to smooth, form, and shape the gum. next, the gum goes through a shaping process that is determined by gum type and consumer demand. for example, cut and wrap (chunk or cube) pieces are severed straight out of the extruder using a vertical cutter. sheeting is a technique often used for stick, slab and tab gums. next, gum is either conditioned by being sprinkled with a powdered polyol or coated via the application of subsequent layers of coating using temperature controlled coating basins before it is sent to packaging. product varieties chewing gum balls chewing gum can come in a variety of formats ranging from 1.4 to 6.9 grams per piece, and products can be differentiated by the consumers' intent to form bubbles or the sugar/sugarless dichotomy. chewing gum typically comes in three formats: tablets, coated pellets, and sticks/ slabs. bubble gum typically come in three formats as well: tablets, hollow balls, and cubes or chunks. stick, slab, and tab gums typically come in packs of about five to 17 sticks or more, and their medium size allows for softer texture. pellet gums, or dragée gums, are pillow shaped pieces that are almost always coated. packaging of pellet gums can vary from boxes to bottles to blister packs. the coating of pellet gum allows for the opportunity for multiple flavor sensations, since coating is done in a layering process and different flavor attributes can be added to various layers. cube or chunk gums, which are typically intended for bubble blowing, are called cut and wrap gums as they are typically severed from continuous strands of extruded gum and packaged directly. quality and safety chewing gum is rather shelf stable because of its non-reactive nature and low moisture content. the water activity of chewing gum ranges from 0.40 to 0.65. the moisture content of chewing gum ranges from three to six percent. in fact, chewing gum retains its quality for so long that, in most countries, it is not required by law to be labeled with an expiration date. if chewing gum remains in a stable environment, over time the gum may become brittle or lose some of its flavor, but it will never be unsafe to eat. if chewing gum is exposed to moisture, over time water migration may occur, making the gum soggy. in lollipops with a gum center, water migration can lead to the end of the product's shelf life, as it causes the exterior hard candy shell to soften and the interior gum center to harden. physical and chemical characteristics the physical and chemical properties of chewing gum impact all aspects of this product, from manufacturing to sensory perception during mastication. chewiness the polymers that make up the main component of chewing gum base are hydrophobic. this property is essential because it allows for retention of physical properties throughout the mastication process. because the polymers of gum repel water, the water-based saliva system in a consumer's mouth will dissolve