Production of Gum:

All gum begins with a latex, or rubbery, type base, generally made from the resin of a tree mixed with a man-made rubber; in this case I will use chicle, from the Sapodilla tree, as my natural rubber example. I am going to take Belize, a country in Central America, as my example of a Sapodilla rich area.



Belize (Right Hand Corner of Central America)



In Belize the wet season stretches from September to February, this is the time when trees such as the Sapodilla are producing the most latex, thus this is the time when they must be harvested. Chicle is still to this day harvested by hand but each tree gives only around 1kg of rubber every 3-4 years this gave need for the introduction of synthetic rubbers in modern, mass produced, gum products.  An example of this synthetic rubber is polyvinyl acetate.

When chicle is harvested from a tree it is ground into small pieces and then compressed in blocks, it is then left in heat to dry out. After the drying process it is generally shipped out to factories in the E.U and U.S.A, there are very few companies who produce the gum inside of Central America (Belize.).

When the chicle blocks arrive in the factory they enter a machine that heats the gum to 116°C, into a syrup like paste, impurities are then filtered out of the chicle. The syrup is poured into large vat where a bladed machine stirs it rapidly. Here is where extra ingredients are added, these include; firstly the synthetic rubber base that makes the majority of the rubber in the gum, then the sugar and corn syrup, followed by the flavourings and softeners. The gum is then rolled to appropriate size and cut into strips for packaging.




Harvesting, preparing and blending chicle.




The majority of any gum is made from sugar and sweeteners although the pure mint gum brands generally contain less than a bubble gum brand. 

References:

http://www.madehow.com/Volume-1/Chewing-Gum.html

http://www.internationalservants.com/www/docs/1/belize-missionaries

http://books.google.ie/books?id=Domy6igYAMYC&pg=PA182&lpg=PA182&dq=chiclero+harvest+sapodilla&source=bl&ots=esMU1MIFia&sig=3YA2XC64DnyuvlZQOkZjSx2_rtE&hl=en&sa=X&ei=75OeT9XuMMbChAecs4GIDw&ved=0CCQQ6AEwAQ#v=onepage&q=chiclero%20harvest%20sapodilla&f=false