Have you ever wondered why jelly wobbles? Puzzled over why salad cream can be poured and mayonnaise cannot? The answer lies with colloids, reports a scientist in the UK.

Eric Dickinson at the University of Leeds has prepared guidelines for predicting the texture and consistency of semi-solid foods.

Jelly, salad dressings, margarines and sauces are semi-solid foods containing combinations of colloidal ingredients. Interactions between proteins, polysaccharides and surfactants in these mixtures determine their textures and consistencies. Until now these interactions have been poorly understood, explains Dickinson. 

                
 
Motivated by a desire to understand these interactions and predict their effect on food textures and consistencies, Dickinson used theoretical modelling and computer simulations to develop guidelines for making such predictions.

His research is significant for the development and use of computer simulations to describe and predict the behaviour of colloids in foods, says Vic Morris, an expert in colloid science at the Institute of Food Research, Norwich, UK.

Dickinson's aim is to observe and understand ingredient interactions taking place during, for example, the mixing of a cream topping or the baking of a cake. 

Nina Athey-Pollard