Could you explain the significance of your article to the non-specialist?

Adding salt to proteins in aqueous solution affects their structure in a complex way. We have simulated a tripeptide in a container of over a thousand water molecules with various dissolved salts. The model shows us how the salts compete with the tripeptide for the water molecules, and leads to counter-intuitive conclusions. For example, some types of ion prefer to be close to charged regions of the peptide, as expected, but others preferentially interact with the greasy parts of the molecule. This gives us new insights into the Hofmeister effect, which has been the subject of discussion for over a century.

What has motivated you to conduct this work?

The liking of any given food does not only depend on the flavors and aromas contained in the food but on the texture (i.e. creaminess, crunchiness, viscosity etc.). The functionality of texturising food polymers like proteins or starch, that are used in food industry as emulisfiers or viscosifiers, often depends of the whole composition of a food. A change in salt and sugar levels might have a dramatic effect on product texture. There is a strong drive to reduce salt and sugar content in food products to make them healthier. To do this it is necessary to understand the effects salt and sugar have on overall texture, so that you don't have to compromise on product quality when you change your recipe. We have used supercomputers to create an atom-scale model of a short strand of a protein, together with the surrounding water molecules and salt. This model shows us what happens to the protein as the amount of salt is varied. This atomic-level world has counter-intuitive behaviour. For example, some charged particles, which we usually expect to interact with objects with the opposite charges, instead are attracted to greasy areas of the molecule. The explanation lies in the competition for water molecules - all ions want them; not all can get them. On a human-sized scale, this contributes to understanding a phenomenon called the Hofmeister effect, which has been puzzling scientists for more than a century.

Where do you see this work developing in the future?

This work gives us some insight in how ingredients in a food interact and potentially create unique textures. Cooking meets cutting edge molecular science.

Are there any particular challenges facing future research in this area?

To extend or research to larger and more complex systems, that might allow us to create a predictive tool to better understand how textures are created in our products.