The secrets inside your saliva - BBC

Scientists have long understood some of saliva's functions: it protects the teeth, makes speech easier and establishes a welcoming environment for foods to enter the mouth.

But when Carpenter and his colleagues studied the process in the lab in a sort of artificial mouth, they found that saliva prevented the soda's bubbles from flowing between tongue and palate.

Volunteers who produced more saliva tended to score the flavours as more intense, possibly because they swallowed more often and thus forced more aromas into their nasal passages, the scientists found.

Sarkar's research uses a mechanical tongue, bathed in artificial saliva, as a way to simulate what happens as food moves through the mouth and how that influences the sensory experience of eating.

Oral biochemist Elsa Lamy of the University of Évora in Portugal investigated this by blindfolding volunteers, letting them smell a piece of bread for about four minutes, while monitoring their saliva for changes.

Lamy's group has done similar experiments with vanilla and lemons, and in all cases found changes in the levels of saliva proteins, though the specific changes depended on the food presented.