Upper Intermediate Stories
The resin is collected from trees the same way rubber is collected. Today manufacturers include sweeteners like cane or beet sugar or a synthetic sweetener like aspartame. They also include glycerin and vegetable oils as softeners.
The changing climate is making trees with the suitable resins increasingly scarce so companies are looking to synthetic substitutes.
Most commercial gums can be swallowed without causing harm. They are not broken down by the digestive system but simply pass along it.
Copyright © 2003 Time4English. All rights reserved.