Quick Dips

Sweet Signals

It's easy to tell when something tastes sweet, but the difficult part is in understanding how sweetness is recognised. Researchers at Auckland University are investigating the structures of molecules that trigger a sweet response. They hope to define the shape that indicates sweetness to taste receptors on the tongue.

Dr Jan Coddington and PhD student Trish Shaw have encountered a number of difficulties in their studies. There is no scientific instrument for measuring sweetness or predicting its intensity. The tongue is perhaps the most appropriate, but volunteer tongues have been few and far between. They've had to develop "imitation" tongues, using egg yolks.

The results have been promising, with sweet substances such as sucrose presenting a specific surface to the egg-derived lipid interface. Coddington and Shaw are now looking at other sweeteners to see if they have surfaces similar to that in sucrose which could be involved in the sweet reaction.