You might as well spit chewing gum out after a couple of minutes. The taste has gone, we say. But we’re wrong, write PhD candidate Emma Hinderink in Food Research International. More than 95 per cent of the aroma and flavour is still in the gum after use.
How flavour is released when we chew our food is still poorly understood. This is partly because it is so difficult to measure the release of taste, explains Hinderink. ‘Every mouth is different. The experience of taste depends on a lot of factors. How fast you eat, how long the food stays in your mouth, the acidity in the mouth, how much saliva you produce, etcetera.’
With a view to standardizing all those variables, the big Swiss aroma and flavouring producer Firmenich has developed an artificial mouth. This is a cylinder with a piston that simulates a chewing movement. Lumps on the piston and on the bottom of the cylinder function like teeth. Water and air flowing in and out represent saliva and breath.
Hinderink, who did an internship at Firmenich, gave the artificial mouth chewing gum to eat which contained a mix of five different commonly used flavourings. The artificial mouth chewed on each piece of gum for a quarter of an hour. Through close analysis of the saliva and the air, Hinderink could monitor how long the flavours lasted. ‘Depending on the kind of flavouring, between two and four per cent of the flavour is released. The rest stays behind and is therefore lost.’
It is also the case that almost all the taste is released in the first couple of minutes, when the water-soluble part of the chewing gum dissolves. Most of the flavourings are not embedded in this part of the chewing gum, but in the tough gum that does not dissolve in saliva. That is why these flavours are only sporadically released during chewing. It is also why the release of flavour turns out to be a bit more complex than we realised. Producers of flavourings, such as Firmenich, can benefit from that knowledge, says Hinderink.