Vanderwaaals

Waaalsbag-a fruit conserving package-with innermost layer made of a spore-like transparent material, a second layer coated with powdered activated carbon-which is an ethylene absorber- It traps the ethylene secreted by the fruits, preventing further production of ethylene, hence delaying ripening. It's outermost layer is transparent as well. This transparency of the material aids the users to track ripening rate as they observe the gradual colour change.