what is the function of calcium carbonate in the chewing gum we eat?

Calcium carbonate is act as a filler in chewing gums which neutralizes the acid and relieves heartburn immediately. While continuing to chew gum will produce saliva, and since Saliva's pH is alkaline, the swallowed saliva will continue to neutralize the remaining acid. Like Tums, Surpass may be used as calcium supplement as well.