View source for Chewing gum

{{Short description|Soft substance meant to be chewed without swallowing}}
{{Other uses}}
{{pp-semi-indef|small=yes}}
{{Use dmy dates|date=August 2021}}
{{Infobox food
| name       = Chewing gum
| image      = Chewing gum stick.jpg
| image_size = 250px
| caption    = An unwrapped stick of chewing gum
| alternate_name=
| country    =
| region     =
| creator    =
| course     =
| type       = [[Confectionery]]
| served     = 
| main_ingredient = [[Gum base]], sweeteners, [[plasticizers]], flavors, colors, [[polyols]]
| variations =
| other      =
}}
'''Chewing gum''' is a soft, cohesive substance designed to be chewed without being swallowed. Modern chewing gum is composed of [[gum base]], sweeteners, softeners/[[plasticizer]]s, flavors, colors, and, typically, a hard or powdered [[polyol]] coating.<ref name=":1" /> 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.<ref name=":2">{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last=Estruch|first=RA|publisher=Kennedy's Publications Ltd.|year=2008|editor-last=Fritz|editor-first=D|edition=2|location=Essex|pages=93–118|chapter=Gum base}}</ref>

== History ==
[[File:Fruit-Stipe-Gum-Sticks.jpg|thumb|right|Sticks of [[Fruit Stripe]] chewing gum]]
[[File:CHICLEROSPCIQUINTANAROO001.jpg|thumb|right|Traditional extraction of chicle from ''chicozapote'' tree ([[Manilkara zapota|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 [[chewing|masticate]]. Early chewers did not necessarily desire to derive nutritional benefits from their chewable substances but at times sought [[stimulus (physiology)#Taste|taste stimuli]] and [[teeth cleaning]] or breath-freshening capabilities.<ref name=":0">{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last=Fenimore|first=EL|publisher=Kennedy's Publications Ltd.|year=2008|isbn=978-0-9558085-2-4|editor-last=Fritz|editor-first=D|location=Essex|pages=1–46|chapter=The History of Chewing Gum, 1849–2004}}</ref>

Chewing gum in many forms has existed since the [[Neolithic]] period. 5,000-year-old chewing gum made from [[birch tar|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.<ref>{{cite news |url=http://news.bbc.co.uk/2/hi/uk_news/6954562.stm |title=Student dig unearths ancient gum |work=BBC News |publisher=BBC |archive-url=https://web.archive.org/web/20170919041614/http://news.bbc.co.uk/2/hi/uk_news/6954562.stm |archive-date=19 September 2017 }}</ref> It is chemically similar to petroleum tar and is in this way different from most other early gum.<ref>{{Cite journal|last1=Fagernäs|first1=Leena|last2=Kuoppala|first2=Eeva|last3=Tiilikkala|first3=Kari|last4=Oasmaa|first4=Anja|title=Chemical Composition of Birch Wood Slow Pyrolysis Products|journal=Energy & Fuels|volume=26|issue=2|pages=1275–83|doi=10.1021/ef2018836|year=2012 |bibcode=2012EnFue..26.1275F }}</ref><ref>{{Cite journal|last1=Kekäläinen|first1=Timo|last2=Venäläinen|first2=Tapani|last3=Jänis|first3=Janne|date=17 July 2014|title=Characterization of Birch Wood Pyrolysis Oils by Ultrahigh-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry: Insights into Thermochemical Conversion|journal=Energy & Fuels|volume=28|issue=7|pages=4596–602|doi=10.1021/ef500849z|bibcode=2014EnFue..28.4596K |issn=0887-0624}}</ref> The [[Maya peoples|Mayans]] and [[Aztecs]] were the first to exploit the positive properties of gum;<ref>{{Cite journal|last=Smithsonian|first=Eeva|title=Brief History of Chewing Gum|url=https://www.smithsonianmag.com/arts-culture/a-brief-history-of-chewing-gum-61020195/|journal=Energy & Fuels|volume=26|issue=2|pages=1275–83|doi=10.1021/ef2018836|year=2012|bibcode=2012EnFue..26.1275F |url-access=subscription}}</ref> they used [[chicle]], a natural [[Natural gum|tree gum]], as a base for making a gum-like substance<ref>{{Cite web|url=https://pubs.acs.org/cen/whatstuff/85/8532sci2.html|title=Chemical & Engineering News: Science & Technology – What's That Stuff? Chewing Gum|website=pubs.acs.org|access-date=9 December 2016}}</ref> and to stick objects together in everyday use. Forms of chewing gum were also chewed in [[Ancient Greece]]. The Ancient Greeks chewed [[Mastic (plant resin)|mastic gum]], made from the resin of the [[Pistacia lentiscus|mastic tree]].<ref>[https://archive.today/20130215115730/http://inventors.about.com/od/gstartinventions/a/gum.html "The History of Chewing Gum and Bubble Gum"] page of [http://wayback.archive-it.org/10702/20120916175411/http://inventors.about.com/ About.com Inventors].</ref> Mastic gum, like birch bark tar, has antiseptic properties and is believed to have been used to maintain oral health.<ref>{{Cite journal|last1=Dimas|first1=Konstantinos S.|last2=Pantazis|first2=Panayotis|last3=Ramanujam|first3=Rama|date=1 October 2016|title=Review: Chios mastic gum: a plant-produced resin exhibiting numerous diverse pharmaceutical and biomedical properties|journal=In Vivo (Athens, Greece)|volume=26|issue=5|pages=777–85|issn=1791-7549|pmid=22949590}}</ref> Both chicle and mastic are tree resins. Many other cultures have chewed gum-like substances made from plants, grasses, and [[resin]]s.
{| class="wikitable"
|+Variations of early chewing gum worldwide<ref name=":0" />
!Ancient civilization
!Chewing gum precursor
|-
|[[Ancient Greece]]
|[[Mastic (plant resin)]]
|-
|[[Ancient Maya]]
|[[Chicle]]
|-
|Ancient Horn of Africa and Yemen
|[[Khat]]
|-
|Chinese
|[[Ginseng]] plant roots
|-
|[[Inuit]]
|[[Blubber]]
|-
|[[Indigenous peoples of the Americas|Native Americans]]
|[[Sugar pine]] and [[spruce]] sap
|-
|[[South American]]s
|[[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 in the United States|American Indians]] chewed [[resin]] made from the [[sap]] of [[spruce]] trees.<ref>{{usurped|1=[http://archive.wikiwix.com/cache/20110703061324/http://beemansgum.org/history/chewing-gum/ "History Of Chewing Gum"]}} page of {{usurped|1=[https://web.archive.org/web/20100608190624/http://beemansgum.org/ BeemarsGum.org]}}.</ref> 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 [[Indigenous peoples of the Americas|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.<ref>{{Cite web|url=http://cen.acs.org/articles/85/i40/Flavoring-Chewing-Gum.html|title=Flavoring Chewing Gum {{!}} Chemical & Engineering News|website=cen.acs.org|access-date=9 December 2016}}</ref> William F. Semple, a dentist from [[Mount Vernon, Ohio]], filed an early patent on chewing gum, patent number 98,304, on 28 December 1869.<ref>{{cite patent |country=US |number=98304A  |inventor= William F. Semple |invent1= |invent2= |status= |title= Improved Chewing Gum |pubdate=1869-12-28  |gdate= |fdate= |pridate= |assign1= |assign2= |url=}}</ref> Semple's gum was intended to clean the teeth and strengthen the chewer's jaw. It was not a sweet treat; ingredients included chalk and powdered [[licorice]] root. Charcoal was also suggested as a "suitable" ingredient in the patent.<ref name=OHC>{{cite web |url=http://www.ohiohistorycentral.org/w/William_F._Semple |archive-url=https://web.archive.org/web/20180623063519/http://www.ohiohistorycentral.org/w/William_F._Semple |archive-date=23 June 2018 |title=William F. Semple |publisher=Ohio History Central (maintained by the [[Ohio Historical Society]]) |access-date=July 17, 2013}}</ref>

[[File:Colgans Taffy Tolu.jpg|thumb|An image of a Colgan's Taffy Tolu Chewing Gum chromolithograph advertisement, {{Circa|1910}}]]The first flavored chewing gum was created in the 1860s by [[John Colgan (pharmacist)|John Colgan]], a Louisville, Kentucky, pharmacist. Colgan mixed with powdered sugar the aromatic flavoring [[Tolu balsam|tolu]], a powder obtained from an extract of the balsam tree (''[[Myroxylon]]''), creating small sticks of flavored chewing gum he named "Taffy Tolu".<ref>{{cite news|url=https://news.google.com/newspapers?nid=266&dat=19781222&id=xwgxAAAAIBAJ&sjid=m-AFAAAAIBAJ&pg=2115,7685650&hl=en|title=It's Flavored Chewing Gum: Taffy Tolu Invention Is Remembered|date=22 December 1978|newspaper=Kentucky New Era|location=Hopkinsville, Christian County, Kentucky|author=<!--Staff writer; George Hackett-->|access-date=8 September 2015}}</ref> 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<ref>{{cite web|url=https://patents.google.com/patent/US966160A/en?q=colgan&q=gum|title=Web-cutting attachment for wrapping-machines|access-date=8 September 2015}}</ref> and a patent for automatically cutting wrappers for sticks of chewing gum: US 913,352 "Web-cutting attachment for wrapping-machines" 23 February 1909<ref>{{cite web|url=https://patents.google.com/patent/US913352A/en?q=colgan&q=gum|title=Web-cutting attachment for wrapping-machines|access-date=8 September 2015}}</ref> 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 (chewing gum maker)|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.<ref name="Emsley, J. 2004 pp. 189–197">{{cite book|title=Vanity, vitality, and virility|publisher=Oxford University Press|year=2004|isbn=978-0-19-280509-6|location=New York|pages=[https://archive.org/details/vanityvitalityvi00emsl/page/189 189–97]|last1=Emsley|first1=J.|url-access=registration|url=https://archive.org/details/vanityvitalityvi00emsl/page/189}}</ref><ref>{{Cite journal|title=I/EC Reports|journal=Industrial & Engineering Chemistry|volume=51|issue=6|pages=30A–40A|doi=10.1021/ie50594a004|year=1959}}</ref> [[Black Jack (gum)|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.<ref name=":0" /> 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.<ref name=":0" /> 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.<ref>{{Cite news|date=26 July 2021|title=Bursting the bubble: how gum lost its cool|newspaper=The Economist|url=https://www.economist.com/1843/2021/07/26/bursting-the-bubble-how-gum-lost-its-cool|access-date=28 July 2021|issn=0013-0613}}</ref>  Others blamed smartphones reducing impulse purchases at the checkout.<ref>{{cite magazine |last1=Azhar |first1=Azeem' |title=The Exponential Age will transform economics forever |url=https://www.wired.co.uk/article/exponential-age-azeem-azhar |access-date=10 September 2021 |magazine=[[Wired (magazine)|Wired]] |date=6 September 2021}}</ref>

Demand for chewing gum also declined during the [[COVID-19 pandemic]], as people were less concerned about [[bad breath]] and impulse purchases also declined. U.S. sales of gum fell about 30 percent, and while demand was back up to the pre-pandemic level in 2023 in dollar terms, this was the result of [[inflation]] as the average price of a pack increased $1.01 from 2018 to $2.71 in 2023. Globally, sales were down 10 percent from 2018.<ref>{{cite news|last=Durbin |first=Dee-Ann |title=Candy companies pitch gum as a stress reliever and concentration aid to revive stale US sales |url=https://apnews.com/article/gum-chewing-popularity-mars-wrigley-ac8251d03c5248d3716988fe144d2333 |access-date=18 March 2024 |work=[[Associated Press]] |date=7 March 2024}}</ref>

== Ingredient composition ==
Gum base composition is considered proprietary information known by select individuals within each gum-manufacturing company.<ref name=":2" /> 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'''''<ref name=":1">{{Cite web|url=http://www.gumassociation.org/index.cfm/science-technology/ingredients-technology/|title=Ingredients technology – ICGA|website=www.gumassociation.org|access-date=15 December 2016}}</ref><ref name=":6">{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last=Mestres|first=J|publisher=Kennedy's Publications Ltd.|year=2008|editor-last=Fritz|editor-first=D|edition=2|pages=47–73|chapter=Modern chewing gum}}</ref>
{| class="wikitable"
!Ingredient
!Percent (by weight) Composition
!Functionality
! colspan="2" |Common examples
|-
|Gum Base<ref name=":2" />
|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.
| colspan="2" |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.
|<u>Bulk polyol sweeteners</u><ref>{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last=Carcasona|first=ER|publisher=Kennedy's Publications Ltd.|year=2008|editor-last=Fritz|editor-first=D|edition=2|location=Essex|pages=119–32|chapter=Bulk sweeteners used in sugar chewing gum}}</ref><u>:</u>
sugar, dextrose, glucose or corn syrup, erythritol, isomalt, xylitol, maltitol, mannitol, sorbitol, lactitol
|<u>Intensive sweeteners</u><ref>{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last1=Ponakla|first1=SV|last2=Corliss|first2=G|last3=Prakash|first3=I|last4=Bishay|first4=I|publisher=Kennedy's Publications Ltd.|year=2008|editor-last=Fritz|editor-first=D|edition=2|location=Essex|pages=157–93|chapter=High-intensity sweeteners in sugar-free chewing gum}}</ref><u>:</u>
aspartame, acesulfame-K, saccharine, sucralose, neohesperidine, dihydrichalcone
|-
|Glycerine
|2–15%
|To maintain moistness
| colspan="2" |
|-
|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.
| colspan="2" |lecithin, hydrogenated vegetable oils, glycerol ester, lanolin, methyl ester, pentaerythritol ester, rice bran wax, stearic acid, sodium and potassium stearates
|-
|Flavors<ref name=":3">{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last=de Roos|first=KB|publisher=Kennedy's Publications Ltd.|year=2008|editor-last=Fritz|editor-first=D|edition=2|location=Essex|pages=205–31|chapter=Flavourings for chewing gum}}</ref>
|1.5–3.0%
|For taste and sensory appeal. Flavor components in gum exist in liquid, powder or [[Micro-encapsulation|micro-encapsulated]] forms.<ref>{{Cite web|url=https://www.fona.com/sites/default/files/Flavor%20Encapsulation_October_2014_v2.pdf|title=Benefits of flavor encapsulation|website=Fona International|archive-url=https://web.archive.org/web/20161220152829/https://www.fona.com/sites/default/files/Flavor%20Encapsulation_October_2014_v2.pdf|archive-date=20 December 2016}}</ref> 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. 
| colspan="2" |Natural or synthetic

Peppermint and spearmint are the most popular flavors.<ref>{{Cite book|url=https://books.google.com/books?id=bHixDgAAQBAJ&pg=PA461|title=Natural and Artificial Flavoring Agents and Food Dyes|last1=Grumezescu|first1=Alexandru Mihai|last2=Holban|first2=Alina Maria|year=2017|publisher=Academic Press|isbn=978-0-12-811269-4|page=461|language=en}}</ref> Food acids are implemented to provide a sour flavor (i.e. citric, tartaric, malic, lactic, adipic, and fumaric acids).
|-
|Colors
|Variable
|For visual appeal
| colspan="2" |Natural or synthetic
|-
|Polyol coating<ref>{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last1=Ladret|first1=M|last2=Le Bot|first2=Y|last3=Nesvadba|first3=S|last4=Ostermann|first4=E|last5=Ribadeau-Dumas|first5=G|publisher=Kennedy's Publications Ltd.|year=2008|editor-last=Fritz|editor-first=D|edition=2|location=Essex|pages=133–55|chapter=Polyols: their properties and applications in sugar-free chewing gum}}</ref>
|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. 
| colspan="2" |Sorbitol
Maltitol/Isomalt

Mannitol

Starch
|}

=== Gum base ===
[[Gum base]] is made of polymers, plasticizers, and resins. [[Polymer]]s, including elastomers, are responsible for the stretchy and sticky nature of chewing gum. [[Plasticizer]]s 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. [[Resin]]s 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.<ref name=":2" />

'''''Table 3: Gum base ingredients approved for use by the U.S. Food and Drug Administration (2016)'''''<ref>{{Cite web|url=https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=172.615|title=CFR – Code of Federal Regulations Title 21|website=www.accessdata.fda.gov|access-date=15 December 2016}}</ref>
{| class="wikitable"
!Natural ingredients
!Synthetic ingredients
|-
|<u>[[Sapotaceae]]</u>
[[Chicle]]

Chiquibul

Crown gum

Gutta hang kang

[[Manilkara bidentata|Massaranduba balata]]

Massaranduba chocolate

[[Manilkara huberi|Nispero]]

Rosidinha

Venezuelan chicle
| rowspan="4" |Butadiene-styrene rubber

Isobutylene-isoprene copolymer ([[butyl rubber]])

Paraffin (via the [[Fischer–Tropsch process]])

[[Petroleum wax]]

Petroleum wax synthetic

[[Polyethylene]]

[[Polyisobutene|Polyisobutylene]]

[[Polyvinyl acetate]]
|-
|<u>[[Apocynaceae]]</u>
Jelutong

[[Couma macrocarpa|Leche caspi]] (sorva)

Pendare

Perillo
|-
|<u>[[Moraceae]]</u>
Leche de vaca

Niger gutta

Tunu (tuno)
|-
|<u>[[Euphorbiaceae]]</u>
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.<ref>{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last=Clark|first=W|publisher=Kennedy's Publications Ltd.|year=2008|editor-last=Fritz|editor-first=D|edition=2|location=Essex|pages=277–91|chapter=Panning}}</ref>

=== Product varieties ===
[[File:Bubble gum at the Haribo factory.jpg|thumb|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.<ref>{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last1=Gand|first1=C|last2=Fritz|first2=D|publisher=Kennedy's Publications Ltd.|year=2008|editor-last=Fritz|editor-first=D|edition=2|location=Essex|pages=253–74|chapter=Chewing gum manufacture}}</ref><ref>{{Cite web|url=http://www.gumassociation.org/index.cfm/science-technology/manufacturing-process//|title=Manufacturing Process – ICGA|website=www.gumassociation.org|access-date=17 December 2016}}</ref>

<gallery mode=packed>
File:Streifenkaugummi.jpg|Stick
File:Kaugummis cropped.jpg|Coated pellets
File:Kauwgum.jpg|Uncoated
</gallery>

=== 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.<ref name=":4">{{Cite book|title=Properties of Water in Foods|last1=Bussiere|first1=G.|last2=Serpelloni|first2=M.|chapter=Confectionery and Water Activity Determination of AW by Calculation |year=1985|publisher=Springer Netherlands|isbn=978-94-010-8756-8|editor-last=Simatos|editor-first=D.|series=NATO ASI Series|pages=627–45|language=en|doi=10.1007/978-94-009-5103-7_38|editor-last2=Multon|editor-first2=J. L.}}</ref> The moisture content of chewing gum ranges from three to six percent.<ref name=":4" /> 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.<ref name=":5">{{Cite book|title=Formulation and Production of Chewing and Bubble Gum|last=Fritz|first=D|publisher=Kennedy's Publications Ltd.|year=2008|editor-last=Fritz|editor-first=D|edition=2|location=Essex|pages=75–90|chapter=Evaluation and shelf-life}}</ref> 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.<ref name=":5" /> 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.<ref name=":2" /> 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 the sugars and flavorings in chewing gum, but not the gum base itself. This allows for gum to be chewed for a long time without breaking down in the mouth like conventional foods. Chewing gum can be classified as a product containing a liquid phase and a crystalline phase, providing gum with its characteristic balance of plastic and elastic properties.<ref name=":1" />

=== Stickiness ===
While [[hydrophobic]] polymers beneficially repel water and contribute to chewiness, they also detrimentally attract oil. The stickiness of gum results from this hydrophobic nature, as gum can form bonds and stick when it makes contact with oily surfaces<ref name=":2" /> such as sidewalks, skin, hair, or the sole of one's shoe. To make matters worse, unsticking the gum is a challenge because the long polymers of the gum base stretch, rather than break. The sticky characteristic of gum may be problematic during processing if the gum sticks to any machinery or packaging materials during processing, impeding the flow of product. Aside from ensuring that the machinery is free from lipid-based residues, this issue can be combatted by the conditioning and coating of gum toward the end of the process. By adding either a powder or a coating to the exterior of the gum product, the hydrophobic gum base binds to the added substance instead of various surfaces with which it may come in contact.

=== Bubble-blowing capability ===
[[File:Blowing bubble gum.jpg|thumb|Bubblegum bubble]]
Bubblegum bubbles are formed when the tension and elasticity of gum polymers acts against the constant and equally dispersed pressure of air being directed into the gum bolus. Bubble gum bubbles are circular because pressure from the focused air being directed into the bolus acts equally on all of the interior surfaces of the gum cud, uniformly pushing outward on all surfaces as the polymers extend. As the bubble expands, the polymers of the gum base stretch and the surface of the bubble begins to thin. When the force of the air being blown into the bubble exceeds the force that the polymers can withstand, the polymers overextend and the bubble pops. Due to the elastic attributes of chewing gum, the deflated bubble recoils and the wad of gum is ready to continue being chewed.<ref name=":2" />

Gum bases with higher molecular weights are typically used in gums intended to meet bubble-forming expectations. Higher molecular weight gum bases include longer polymers that are able to stretch further, and thus are able to form larger bubbles that retain their shape for a longer time.<ref name=":2" />

=== Flavor release ===
Flavor delivery is extended throughout the mastication process by timed release of different flavor components due to the physical-chemical properties of many of chewing gum's ingredients. During the first three to four minutes of the chew, bulking agents such as sugar or sorbitol and maltitol have the highest [[solubility]] and, therefore, are chewed out first. As these components dissolve in the consumers' saliva and slide down the esophagus, they are no longer retained in the gum base or perceived by the chewer. During the next phase of the chew in the four to six-minute range, intense sweeteners and some acids are dissolved and chewed out. These components last slightly longer than the bulking agents because they have a slightly lower solubility. Next, encapsulated flavors are released during either 10–15 minutes into the chew or after 30–45 minutes. Encapsulated flavors remain incorporated in the gum base longer because the molecules that they are encapsulated in are more easily held within the gum matrix. Finally, during the last phase of the chew, softeners such as corn syrup and glycerin and other textural modifiers are dissolved, resulting in a firming up of the gum and the end of the chew.<ref name=":3" />

Studies have shown that gum flavor is perceived better in the presence of sweetener.<ref>{{Cite journal|last1=Davidson|first1=J. M.|last2=Linforth|first2=R. S.|last3=Hollowood|first3=T. A.|last4=Taylor|first4=A. J.|date=1 October 1999|title=Effect of sucrose on the perceived flavor intensity of chewing gum|journal=Journal of Agricultural and Food Chemistry|volume=47|issue=10|pages=4336–40|issn=0021-8561|pmid=10552812|doi=10.1021/jf9901082 |bibcode=1999JAFC...47.4336D }}</ref> Companies have started to create chemical systems in gum so that the sweetener and flavor release together in a controlled manner during chewing.<ref>{{Cite journal|last1=Potineni|first1=Rajesh V.|last2=Peterson|first2=Devin G.|title=Mechanisms of Flavor Release in Chewing Gum: Cinnamaldehyde|journal=Journal of Agricultural and Food Chemistry|volume=56|issue=9|pages=3260–67|doi=10.1021/jf0727847|pmid=18426214|year=2008 |bibcode=2008JAFC...56.3260P }}</ref>

=== Cooling sensation ===
A cooling sensation is achieved through the chemical phenomenon of the negative [[Enthalpy of solution|enthalpy of dissolution]] that occurs with bulk sweeteners, such as the sugar alcohols. The enthalpy of dissolution refers to the overall amount of heat that is absorbed or released in the dissolving process. Because the bulk sweeteners absorb heat as they dissolve and have a negative enthalpy, they yield a cooling sensation as they are dissolved in a consumer's saliva.<ref name=":1" /><ref name=":6" />

==Health effects==

===Brain function===
A review about the cognitive advantages of chewing gum by Onyper et al. (2011) found strong evidence of improvement for the following cognitive domains: [[working memory]], [[episodic memory]] and speed of [[perception]]. However the improvements were only evident when chewing took place prior to cognitive testing. The precise mechanism by which gum chewing improves cognitive functioning is however not well understood.
The researchers did also note that chewing-induced arousal could be masked by the distracting nature of chewing itself, which they named "dual-process theory", which in turn could explain some of the contradictory findings by previous studies. They also noticed the similarity between mild physical exercise such as pedaling a stationary bike and chewing gum. It has been demonstrated that mild physical exercise leads to little cognitive impairment during the physical task accompanied by enhanced cognitive functioning afterwards. Furthermore, the researchers noted that no improvement could be found for verbal fluency, which is in accordance with previous studies. This finding suggests that the effect of chewing gum is domain specific. The cognitive improvements after a period of chewing gum have been demonstrated to last for 15–20 minutes and decline afterwards.<ref>{{cite journal |doi=10.1016/j.appet.2011.05.313 |pmid=21645566 |title=Cognitive advantages of chewing gum. Now you see them, now you don't |journal=Appetite |volume=57 |issue=2 |pages=321–28 |year=2011 |last1=Onyper |first1=Serge V. |last2=Carr |first2=Timothy L. |last3=Farrar |first3=John S. |last4=Floyd |first4=Brittney R. |s2cid=18821962 }}</ref>{{qualify evidence}}<!-- Has this effect been replicated?  Do other scientific authors accept the conclusions of this review? -->

===Dental health===

Sugar-free gum sweetened with [[xylitol]] has been shown to reduce cavities and [[Dental plaque|plaque]].<ref name="polyol">{{cite journal |doi=10.14219/jada.archive.2008.0102 |pmid=19047666 |title=The impact of polyol-containing chewing gums on dental caries |journal=The Journal of the American Dental Association |volume=139 |issue=12 |pages=1602–14 |year=2008 |last1=Deshpande |first1=Amol |last2=Jadad |first2=Alejandro R. |doi-access=free }}</ref><ref>{{Cite journal |last1=ALHumaid |first1=Jehan |last2=Bamashmous |first2=Mohamed |date=2022 |title=Meta-analysis on the Effectiveness of Xylitol in Caries Prevention |journal=Journal of International Society of Preventive and Community Dentistry |language=en-US |volume=12 |issue=2 |pages=133–138 |doi=10.4103/jispcd.JISPCD_164_21 |doi-access=free |pmid=35462747 |pmc=9022379 |issn=2231-0762}}</ref><ref>{{Cite journal |last1=Söderling |first1=Eva |last2=Pienihäkkinen |first2=Kaisu |date=2022 |title=Effects of xylitol chewing gum and candies on the accumulation of dental plaque: a systematic review |journal=Clinical Oral Investigations |volume=26 |issue=1 |pages=119–129 |doi=10.1007/s00784-021-04225-8 |issn=1432-6981 |pmc=8791908 |pmid=34677696}}</ref> The sweetener [[sorbitol]] has the same benefit, but is only about one-third as effective as xylitol.<ref name="polyol" /> Other sugar substitutes, such as [[maltitol]], aspartame and acesulfame K, have also been found to not cause [[tooth decay]].<ref name="Emsley, J. 2004 pp. 189–197"/><ref>{{cite journal |pmid=24313583 |year=2013 |last1=Thabuis |first1=C |title=Effects of maltitol and xylitol chewing-gums on parameters involved in dental caries development |journal=European Journal of Paediatric Dentistry |volume=14 |issue=4 |pages=303–08 |last2=Cheng |first2=C. Y. |last3=Wang |first3=X |last4=Pochat |first4=M |last5=Han |first5=A |last6=Miller |first6=L |last7=Wils |first7=D |last8=Guerin-Deremaux |first8=L }}</ref> Xylitol is specific in its inhibition of ''[[Streptococcus mutans]]'', bacteria that are significant contributors to tooth decay.<ref name="Milgrom">{{cite journal |doi=10.1177/154405910608500212 |pmid=16434738 |pmc=2225984 |title=Mutans Streptococci Dose Response to Xylitol Chewing Gum |journal=Journal of Dental Research |volume=85 |issue=2 |pages=177–81 |year=2006 |last1=Milgrom |first1=P. |last2=Ly |first2=K.A. |last3=Roberts |first3=M.C. |last4=Rothen |first4=M. |last5=Mueller |first5=G. |last6=Yamaguchi |first6=D.K. }}</ref> Xylitol inhibits ''Streptococcus mutans'' in the presence of other sugars, with the exception of [[fructose]].<ref>{{cite journal |doi=10.1159/000073391 |pmid=14571117 |title=Xylitol Inhibition of Acid Production and Growth of Mutans Streptococci in the Presence of Various Dietary Sugars under Strictly Anaerobic Conditions |journal=Caries Research |volume=37 |issue=6 |pages=404–09 |year=2003 |last1=Kakuta |first1=Hatsue |last2=Iwami |first2= Yoshimichi |last3=Mayanagi |first3=Hideaki |last4=Takahashi |first4=Nobuhiro |s2cid=21574455 }}</ref> Xylitol is a safe sweetener that benefits teeth and saliva production because, unlike most sugars, it is not fermented to acid.<ref name="Emsley, J. 2004 pp. 189–197"/> Daily doses of xylitol below 3.44&nbsp;grams are ineffective and doses above 10.32&nbsp;grams show no additional benefit.<ref name="Milgrom"/> Other active ingredients in chewing gum include [[fluoride]], which strengthens tooth enamel, and p-chlorbenzyl-4-methylbenzylpiperazine, which prevents [[travel sickness]]. Chewing gum also increases saliva production.<ref name="Emsley, J. 2004 pp. 189–197"/>

Food and sucrose have a demineralizing effect upon [[Tooth enamel|enamel]] that has been reduced by adding [[calcium lactate]] to food.<ref>{{cite journal |doi=10.1159/000262434 |pmid=9353582 |title=Effectiveness of Calcium Lactate Added to Food in Reducing Intraoral Demineralization of Enamel |journal=Caries Research |volume=31 |issue=6 |pages=429–33 |year=1997 |last1=Kashket |first1=S. |last2=Yaskell |first2=T. }}</ref> Calcium lactate added to toothpaste has reduced [[Calculus (dental)|calculus]] formation.<ref>{{cite journal |doi=10.1159/000261550 |pmid=8402801 |title=Control of Calculus Formation by a Dentifrice Containing Calcium Lactate |journal=Caries Research |volume=27 |issue=4 |pages=277–79 |year=1993 |last1=Schaeken |first1=M.J.M. |last2=Van Der Hoeven |first2=J.S. }}</ref> One study has shown that calcium lactate enhances enamel [[Remineralisation of teeth|remineralization]] when added to xylitol-containing gum,<ref>{{cite journal |doi=10.1159/000088905 |pmid=16352880 |title=The Effect of Adding Calcium Lactate to Xylitol Chewing Gum on Remineralization of Enamel Lesions |journal=Caries Research |volume=40 |issue=1 |pages=43–46 |year=2006 |last1=Suda |first1=R. |last2=Suzuki |first2=T. |last3=Takiguchi |first3=R. |last4=Egawa |first4=K. |last5=Sano |first5=T. |last6=Hasegawa |first6=K. |s2cid=45316316 }}</ref> but another study showed no additional remineralization benefit from calcium lactate or other calcium compounds in chewing-gum.<ref>{{cite journal |doi=10.1159/000098043 |pmid=17284911 |title=Effects of Various Forms of Calcium Added to Chewing Gum on Initial Enamel Carious Lesions in situ |journal=Caries Research |volume=41 |issue=2 |pages=108–14 |year=2007 |last1=Schirrmeister |first1=J.F. |last2=Seger |first2=R.K. |last3=Altenburger |first3=M.J. |last4=Lussi |first4=A. |last5=Hellwig |first5=E. |s2cid=22686522 |url=https://boris.unibe.ch/23164/ }}</ref>

Other studies<ref>{{cite journal |doi=10.1034/j.1600-0528.2001.290407.x |pmid=11515642 |title=Caries preventive effect of sugar-substituted chewing gum |journal=Community Dentistry and Oral Epidemiology |volume=29 |issue=4 |pages=278–88 |year=2001 |last1=Machiulskiene |first1=Vita |last2=Nyvad |first2=Bente |last3=Baelum |first3=Vibeke }}</ref> indicated that the caries preventive effect of chewing sugar-free gum is related to the chewing process itself rather than being an effect of gum sweeteners or additives, such as [[polyols]] and [[carbamide]]. A study investigating the in situ effect of casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) found that its incorporation into a sugar-free gum increases the remineralization / protection of eroded enamel surface significantly.<ref>{{Cite journal|last1=de Oliveira |first1=A.F.B. |last2=de Oliveira Diniz |first2=L.V. |last3=Forte |first3=F.D.S. |display-authors=etal|date=28 March 2016|title=In Situ Effect of a CPP-ACP Chewing Gum on Enamel Erosion Associated or Not With Abrasion|url=https://www.ncbi.nlm.nih.gov/labs/articles/27020912/|archive-url=https://web.archive.org/web/20171021104442/https://www.ncbi.nlm.nih.gov/labs/articles/27020912/|archive-date=21 October 2017|journal=Clinical Oral Investigations|volume= 21|issue=1 |pages=339–46|doi=10.1007/s00784-016-1796-1|pmid=27020912 |s2cid=10126499 }}</ref>

Gum chewing is regarded as a helpful way to cure [[halitosis]] (bad breath). Chewing gum not only helps to add freshness to breath but can aid in removing food particles and bacteria associated with bad breath from teeth. It does this by stimulating saliva, which essentially washes out the mouth. Chewing sugar-free gum for 20 minutes after a meal helps prevent tooth decay, according to the American Dental Association, because the act of chewing the sugar-free gum produces saliva to wash away bacteria, which protects teeth.<ref name="benefits of chewing gum">{{cite web |last=Gajilan |first=Chris |title=Chew on this: Gum may be good for body, mind |url=http://www.cnn.com/2009/HEALTH/04/22/chewing.gum.benefits/ |publisher=CNN |access-date=24 September 2013}}</ref> Chewing gum can also help with the lack of saliva or xerostomia since it naturally stimulates saliva production.<ref name="Emsley, J. 2004 pp. 189–197"/> Saliva can also promote enamel remineralization as long as it does not become too acidic.<ref name="Emsley, J. 2004 pp. 189–197"/>

Masumoto et al. looked at the effects of chewing gum after meals following an orthodontic procedure, to see if chewing exercises caused subjects pain or discomfort, or helped maintain a large [[Occlusion (dentistry)|occlusal contact area]]. 35 adult volunteers chewed gum for 10 to 15 minutes before or after three meals each day for 4 weeks. 90% of those questioned said that the gum felt "quite hard", and half reported no discomfort.<ref>{{cite journal |doi=10.1111/j.1365-2842.2009.02010.x |pmid=19845836 |title=Daily chewing gum exercise for stabilizing the vertical occlusion |journal=Journal of Oral Rehabilitation |volume=36 |issue=12 |pages=857–63 |year=2009 |last1=Masumoto |first1=N. |last2=Yamaguchi |first2=K. |last3=Fujimoto |first3=S. }}</ref>{{qualify evidence}}<!-- This is a rather small study; has it been replicated? -->

===Use in surgery===
Several [[randomized controlled studies]] have investigated the use of chewing gum in reducing the duration of post-operative [[ileus]] following abdominal and specifically gastrointestinal surgery. A systematic review of these suggests gum chewing, as a form of "[[sham feeding]]", is a useful treatment therapy in open abdominal or pelvic surgery, although the benefit is less clear when laparoscopic surgical techniques are used.<ref>{{cite journal |doi=10.1007/s00268-009-0104-5 |pmid=19763686 |title=Systematic Review and Meta-Analysis of Chewing-Gum Therapy in the Reduction of Postoperative Paralytic Ileus Following Gastrointestinal Surgery |journal=World Journal of Surgery |volume=33 |issue=12 |pages=2557–66 |year=2009 |last1=Fitzgerald |first1=J. Edward F. |last2=Ahmed |first2=Irfan |s2cid=24548626 }}</ref>

Chewing gum after a colon surgery helps the patient recover sooner. If the patient chews gum for fifteen minutes for at least four times per day, it will reduce their recovery time by a day and a half.<ref name="Chewing Gum Speeds Surgery Recovery">{{cite journal |doi=10.1111/j.1471-0528.2009.02225.x |pmid=19523094 |title=Gum chewing stimulates early return of bowel motility after caesarean section |journal=BJOG |volume=116 |issue=10 |pages=1334–39 |year=2009 |last1=Abd-El-Maeboud |first1=KHI |last2=Ibrahim |first2=MI |last3=Shalaby |first3=DAA |last4=Fikry |first4=MF |doi-access=free}}
*{{cite web |author=Leah Zerbe |date=2 September 2009 |title=Chewing Gum Speeds Surgery Recovery |website=Rodale |url=http://www.rodalenews.com/recovery-after-c-section |archive-url=https://web.archive.org/web/20140309034936/http://www.rodalenews.com/recovery-after-c-section |archive-date=2014-03-09}}</ref> The average patient took 0.66 fewer days to pass gas and 1.10 fewer days to have a bowel movement.<ref name="Chewing Gum Associated With Enhanced Bowel Recovery After Colon Surgery">{{cite journal |doi=10.1001/archsurg.143.8.788 |pmid=18711040 |title=Meta-analysis of Randomized Studies Evaluating Chewing Gum to Enhance Postoperative Recovery Following Colectomy |journal=Archives of Surgery |volume=143 |issue=8 |pages=788–93 |year=2008 |last1=Purkayastha |first1=Sanjay |last2=Tilney |first2=H. S. |last3=Darzi |first3=A. W. |last4=Tekkis |first4=P. P. |doi-access=free}}
*{{cite press release |date=19 August 2008 |title=Chewing Gum Associated With Enhanced Bowel Recovery After Colon Surgery |website=ScienceDaily |url=https://www.sciencedaily.com/releases/2008/08/080818183936.htm}}</ref> Saliva flow and production is stimulated when gum is chewed. Gum also gets digestive juices flowing and is considered "sham feeding".<ref name="Chewing Gum Associated With Enhanced Bowel Recovery After Colon Surgery"/> Sham feeding is the role of the central nervous system in the regulation of gastric secretion.

===Use in cardiovascular disease===
Chewing gum has been shown to be effective in relieving the symptom of thirst in patients living with heart failure.<ref>{{Cite journal|last1=Allida |first1=S. M. |last2=Shehab |first2=S. |last3=Inglis |first3=S. C. |last4=Davidson |first4=P. M. |last5=Hayward |first5=C. S. |last6=Newton |first6=P. J. |url=https://www.heartlungcirc.org/article/S1443-9506(20)30480-7/fulltext|title=A RandomisEd ControLled TrIal of ChEwing Gum to RelieVE Thirst in Chronic Heart Failure (RELIEVE-CHF) - Heart, Lung and Circulation |journal=Heart, Lung & Circulation |date=2021 |volume=30 |issue=4 |pages=516–524 |doi=10.1016/j.hlc.2020.09.004 |pmid=33032897 }}</ref>

===Stomach===
Chewing gum is used as a novel approach for the treatment of [[gastroesophageal reflux disease]] (GERD). One hypothesis is that chewing gum stimulates the production of more bicarbonate-containing [[saliva]] and increases the rate of swallowing. After the saliva is swallowed, it neutralizes acid in the [[esophagus]]. In effect, chewing gum exaggerates one of the normal processes that neutralize acid in the esophagus.<ref>{{cite news |last=Girdwain |first=Jessica |url=https://www.menshealth.com/health/a19537486/no-medicine-cures/ |title=6 'No Medicine' Cures! |work=[[Men's Health]] |date=2014-01-22 |access-date=2022-09-23 }}</ref> However, chewing gum is sometimes considered to contribute to the development of [[stomach ulcers]]. It stimulates the stomach to secrete acid and the [[pancreas]] to produce digestive enzymes that aren't required.<ref>{{Cite web |title=Are there any known health risks from chewing gum (aside from the risk of accidentally swallowing it)? {{!}} Notes and Queries {{!}} guardian.co.uk |url=https://www.theguardian.com/notesandqueries/query/0,,-2787,00.html |access-date=2022-03-11 |website=www.theguardian.com}}</ref> In some cases, when consuming large quantities of gum containing sorbitol, gas and/or diarrhea may occur.<ref>{{Cite web |date=January 26, 2017 |first=Kristin |last=Canning |title=Chewing Tons of Gum Can Actually Cause Diarrhea |url=https://www.health.com/condition/digestive-health/sugar-free-gum-sorbitol-diarrhea |access-date=2022-03-11 |website=Health.com |language=en}}</ref>

===Microplastics===
Chewing gum releases [[microplastics]] and nanoplastics into saliva as it's being chewed, and these particles enter the body when that saliva is swallowed.<ref>{{Cite journal |last=Lowe |first=Lisa |last2=Leonard |first2=Jamie |last3=Mohanty |first3=Sanjay |date=2025-11-01 |title=Ingestion of microplastics during chewing gum consumption |url=https://www.sciencedirect.com/science/article/pii/S2666911025000243 |journal=Journal of Hazardous Materials Letters |volume=6 |article-number=100164 |doi=10.1016/j.hazl.2025.100164 |issn=2666-9110|doi-access=free }}</ref><ref>{{Cite journal |last=Pant |first=Udit |last2=Tate |first2=James |last3=Liu |first3=Xiaotong |last4=Birse |first4=Nicholas |last5=Elliott |first5=Christopher |last6=Cao |first6=Cuong |date=2025-03-15 |title=From automated Raman to cost-effective nanoparticle-on-film (NPoF) SERS spectroscopy: A combined approach for assessing micro- and nanoplastics released into the oral cavity from chewing gum |url=https://www.sciencedirect.com/science/article/pii/S0304389424035593 |journal=Journal of Hazardous Materials |volume=486 |article-number=136978 |doi=10.1016/j.jhazmat.2024.136978 |issn=0304-3894|doi-access=free }}</ref> Multiple potential heath risks have been identified from ingestion of microplastics, but the full [[Microplastics and human health|effects on human health]] are still under investigation.

== Controversies ==

=== Classification as food ===
Controversy arises as to health concerns surrounding the questionable classification of gum as food, particularly in regard to some alternative uses for gum base ingredients. According to the [[Food and Drug Administration|U.S. Food and Drug Administration]] (FDA), chewing gum is considered a food, as the term "food" means "a raw, cooked, or processed edible substance, ice, beverage, or ingredient used or intended for use or for sale in whole or in part for human consumption, or chewing gum".<ref>{{Cite web|url=https://www.fda.gov/Food/GuidanceRegulation/RetailFoodProtection/FoodCode/ucm186464.htm|archive-url=https://web.archive.org/web/20130321120720/http://www.fda.gov/Food/GuidanceRegulation/RetailFoodProtection/FoodCode/ucm186464.htm|archive-date=21 March 2013|title=Food Code – FDA Food Code 2009: Chapter 1 – Purpose & Definitions|website=www.fda.gov|language=en|access-date=17 December 2016}}</ref> Chewing gum is defined as a food of [[minimal nutritional value]].<ref>{{cite web|url=https://www.fns.usda.gov/school-meals/foods-minimal-nutritional-value|archive-url=https://web.archive.org/web/20150528145328/http://www.fns.usda.gov/school-meals/foods-minimal-nutritional-value|archive-date=28 May 2015|title=Foods of Minimal Nutritional Value|date=13 September 2013|website=www.fns.usda.gov|series=Appendix B of 7 CFR Part 210|publisher=[[Food and Nutrition Service]], United States Department of Agriculture|language=en|access-date=4 August 2017}}</ref> However, many of the ingredients in gum base have uses in inedible products, which raises concern in some consumers. Polyethylene, one of the most popular components of gum base, belongs to a common group of plastics and is used in products from plastic bags to hula hoops. [[Polyvinyl acetate]] is a sticky polymer found in white glue. [[Butyl rubber]] is typically used in caulking and the lining of car tires, in addition to its role in gum base. [[Paraffin wax]] is a byproduct of refined petroleum.<ref>{{Cite news|url=https://www.scienceworld.ca/ever-wonder-about-bubble-gum|title=Ever Wonder About Bubble Gum?|date=24 September 2013|newspaper=Science World British Columbia|access-date=17 December 2016}}</ref>

===Possible carcinogens===
Concern has arisen about the possible [[carcinogenicity]] of the [[vinyl acetate]] (acetic acid ethenyl ester) used by some manufacturers in their [[gum base]]s. Currently, the ingredient can be hidden in the catch-all term "gum base". The Canadian government at one point classified the ingredient as a "potentially high hazard substance."<ref>{{cite web |url=http://www.canada.com/topics/bodyandhealth/story.html?id=06e4fd58-ebb9-4bd3-b239-d0f87b743155 |title=Substance found in chewing gum could be labelled toxic |publisher=Canada.com |date=30 May 2008 |access-date=25 January 2012 |archive-url=https://web.archive.org/web/20120211171235/http://www.canada.com/topics/bodyandhealth/story.html?id=06e4fd58-ebb9-4bd3-b239-d0f87b743155 |archive-date=11 February 2012 }}</ref> However, on 31 January 2010, the Government of Canada's final assessment concluded that exposure to vinyl acetate is not considered to be harmful to human health.<ref>{{cite web|url=http://www.ec.gc.ca/ese-ees/59EC93F6-2C5D-42B4-BB09-EB198C44788D/batch2_108-05-4_pc_en.pdf |title=Summary of Public Comments Received on the Government of Canada's Draft Screening Assessment Report and Risk Management Scope on Bisphenol A |access-date=25 January 2012}}</ref> This decision under the [[Canadian Environmental Protection Act, 1999|Canadian Environmental Protection Act]] (CEPA) was based on new information received during the public comment period, as well as more recent information from the risk assessment conducted by the European Union.

===Choking and excretion of swallowed gum===
Various myths hold that swallowed gum will remain in a human's stomach for up to seven years, as it is not [[Period of digestion|digestible]]. According to several medical opinions, there seems to be little truth behind the tale. In most cases, swallowed gum will pass through the system as quickly as any other food.<ref name="sciam.com">{{cite web|last=Matson |first=John |url=http://www.sciam.com/article.cfm?id=fact-or-fiction-chewing-gum-takes-seven-years-to-digest |title=Fact or Fiction?: Chewing Gum Takes Seven Years to Digest: Scientific American |publisher=Sciam.com |access-date=25 January 2012}}</ref>

There have been cases where swallowing gum has resulted in complications in young children requiring medical attention. A 1998 paper describes a four-year-old boy being referred with a two-year history of constipation. The boy was found to have "always swallowed his gum after chewing five to seven pieces each day", being given the gum as a reward for good behavior, and the build-up resulted in a solid mass which could not leave the body.<ref name="pediatrics">{{cite journal |doi=10.1542/peds.102.2.e22 |pmid=9685468 |title=Chewing Gum Bezoars of the Gastrointestinal Tract |journal=Pediatrics |volume=102 |issue=2 |article-number=e22 |year=1998 |last1=Milov |first1=D. E. |last2=Andres |first2=J. M. |last3=Erhart |first3=N. A. |last4=Bailey |first4=D. J. |doi-access=free }}</ref> A 1½-year-old girl required medical attention when she swallowed her gum and four coins, which got stuck together in her esophagus.<ref name="sciam.com"/><ref name="pediatrics"/> A [[bezoar]] is formed in the stomach when food or other foreign objects stick to gum and build up, causing intestinal blockage.<ref>{{cite journal |doi=10.1016/S0016-5107(04)00162-2 |pmid=15173807 |title=Chewing gum bezoar |journal=Gastrointestinal Endoscopy |volume=59 |issue=7 |page=872 |year=2004 |last1=Rimar |first1=Yossi |last2=Babich |first2=Jay P |last3=Shaoul |first3=Ron }}</ref> As long as the mass of gum is small enough to pass out of the [[stomach]], it will likely pass out of the body easily,<ref name="sciam-2">"...eventually the normal housekeeping waves in the digestive tract will sort of push it through, and it will come out pretty unmolested."</ref> but it is recommended that gum not be swallowed or given to young children who do not understand not to swallow it.<ref name="pediatrics"/>

Adults have choked to death on chewing gum in rare cases. A 2012 report describes a 42-year-old woman who fell on the stairs while chewing gum. Due to the impact, the gum fell into the [[pharynx]] and was inhaled into the [[larynx]], causing complete blockage and resulting in the woman's death by [[asphyxia]]tion.<ref>{{Cite journal|last1=Barbera|first1=Nunziata|last2=Arcifa|first2=Veronica|last3=Valenti|first3=Vincenzo|last4=Spadaro|first4=Giorgio|last5=Tomasello|first5=Sergio|last6=Romano|first6=Guido|date=2012|title=Fatal asphyxia by complete laryngeal obstruction due to chewing-gum aspiration in an adult woman|journal=Romanian Journal of Legal Medicine|volume=20|pages=33–36|doi=10.4323/rjlm.2012.33}}</ref>

=== Environmental effects ===
[[File:Chewing gum on a sidewalk in Reykjavík.JPG|thumb|upright|Chewing gum on a sidewalk in [[Reykjavík]]]]Chewing gum is not water-soluble and unlike other confectionery is not fully consumed. There has been much effort at public education and investment aimed at encouraging responsible disposal. Despite this it is commonly found stuck underneath benches, tables, handrails and escalators. It is extremely difficult and expensive to remove once "walked in" and dried. Gum bonds strongly to asphalt and rubber shoe soles because they are all made from polymeric [[hydrocarbons]]. It also bonds strongly with concrete paving. Removal is generally achieved by steam jet and scraper but the process is slow and labour-intensive.

Most external urban areas with high pedestrian traffic show high incidence of casual chewing gum discard. In 2000 a study on [[Oxford Street]], one of London's busiest shopping streets, showed that a quarter of a million black or white blobs of chewing gum were stuck to its pavement.<ref name="Emsley, J. 2004 pp. 189–197"/> Gum removal from city streets, or even famous landmarks, can be a costly effort; in Rome, 15,000 pieces of chewed gum are discarded on a daily basis and the removal of each piece costs the city one euro.<ref>{{Cite news|url=http://www.nydailynews.com/life-style/eats/rome-declares-war-chewing-gum-gum-removal-costs-city-euro-eternal-city-sanitation-article-1.993824|title=Rome declares war on chewing gum|newspaper=Daily News|year=2011}}</ref> However, likely as a consequence of Singapore's ban, Singapore's pavements are, perhaps uniquely amongst modern cities, free of gum.

Various teams of researchers have developed gum that is less adhesive and degrades within days or weeks.<ref>{{Cite web|url=https://www.confectionerynews.com/Article/2013/01/04/Rev7-branded-degradable-gum-exits-US-as-maker-seeks-licensees|title=Rev7 branded degradable gum exits US as maker seeks licensees|date=4 January 2013|website=confectionerynews.com}}</ref><ref>{{Cite news|url=https://www.technologyreview.com/s/408793/nonstick-chewing-gum/|title=Nonstick Chewing Gum|last=Patel|first=Prachi|newspaper=MIT Technology Review|access-date=9 December 2016}}</ref> One example, [[Rev7 Gum]], was briefly for sale from 2010 to 2012.

=== Bans ===
{{See also|Chewing gum ban in Singapore}}Many schools do not allow chewing gum because students often dispose of it inappropriately (leaving it under desks and chairs, behind vending machines, etc.). The chewing may also pose a distraction to class, and the gum might carry diseases or bacteria from other students.<ref>{{cite news|url=https://timesofindia.indiatimes.com/city/bangalore/B-schools-ban-chewing-gum-on-campus/articleshow/4703966.cms|archive-url=https://web.archive.org/web/20131114003134/http://articles.timesofindia.indiatimes.com/2009-06-26/bangalore/28209209_1_gum-cell-phones-draconian-ban|url-status=live|archive-date=14 November 2013|title=B-schools ban chewing gum on campus|date=26 June 2009|work=[[The Times of India]]|access-date=2 August 2010}}</ref>

The Singapore government outlawed chewing gum in 1992 citing the danger of discarded gum being wedged in the sliding doors of underground trains and general cleanliness. However, in 2004 the government allowed sugarless gum to be sold in pharmacies if a doctor or dentist prescribed it due to the [[Singapore–United States Free Trade Agreement]].<ref>{{cite news|url=https://www.bbc.com/news/magazine-32090420|title=Why Singapore banned chewing gum|date=28 March 2015|author=Elle Metz}}</ref>

== Recycling ==
[[File:Gumdrop collector, Caldicot.jpg|thumb|upright|Gumdrop chewing gum collecting bin]]
In 2018, the BBC published a news article on British designer Anna Bullus, who created a method of collecting and recycling chewing gum into plastic, noting that litter from chewing gum is the second most common form of litter, second only to cigarette litter. She uses a Worcester recycling plant to make old chewing gum into plastic. She then uses that plastic at a plastic moulding specialist, Amber Valley, in Leicester to make plastic objects. Known objects made are collection containers for more chewing gum, shoe soles, rubber boots, and plastic cups.<ref>{{Cite news|url=https://www.bbc.com/news/stories-43198104|title=The chewing gum you don't mind stuck to your shoe|last=Shaw|first=Dougal|date=6 March 2018|work=BBC News|access-date=6 March 2018|language=en-GB}}</ref> Her company advertises itself as the "first company in the world to recycle and process chewing gum into a range of new compounds that can be used in the rubber and [[plastics industry]]". The company is called Gum-tec, and the collection containers are dubbed "gumdrops". Advertised products on the website are pencils, coffee mugs, guitar picks, a "bicycle spoke", rulers, sports cones, frisbees, boomerangs, door stops, "meal mates", lunch-boxes, and combs.<ref>{{Cite web|url=http://gumdropltd.com/|title=Gumdrop Ltd.|website=gumdropltd.com|access-date=7 March 2018}}</ref>

==See also==
*[[Bubble gum]]
*[[List of chewing gum brands]]
*[[Bubblegum Alley]]
*[[Gum Wall]] in [[Seattle]]
*[[Gum base]]
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==References==
{{Reflist|30em}}

==External links==
{{Commons category}}
*{{Cite NIE|wstitle=Chewing-Gum|short=x}}
{{Candy}}
{{Non-timber forest products}}
{{Dosage forms|state=expanded}}
{{Authority control}}

{{DEFAULTSORT:Chewing Gum}}
[[Category:Chewing gum| ]]