Transformation of heated meat substitutes is unpredictable

Researchers in the Netherlands have investigated the molecular structure of plant proteins that must provide alternatives for the animal proteins in our food over the next 10 years. They discovered that proteins with a similar chemical structure behaved differently after heating. The behaviour of the proteins after heating plays an important role in the development of a new type of meat substitute product.

Francesca O’Kane used various proteins from peas and soya for her research. After heating the plant proteins formed a gel from which she could deduce the structure of the proteins after heating. Although the pea protein legumin has a structure which is very similar to the soya protein glycinin, O’Kane discovered clear differences between the two proteins after heating. The gel of the soya protein could be repeatedly heated without the gel losing its strength or flexibility. This was not possible with the pea protein gel, due to its unusual spatial structure. Upon repeated heating this gel became increasingly stiff.

The greatest stumbling block in the design of foodstuffs using non-animal proteins is the unpredictability of the final product’s structure, the so-called texture. O’Kane used several proteins from peas to map the behaviour of plant proteins. She followed the molecular structure of the proteins in three stages: the unfolding during heating, the aggregation after heating and the eventual formation of a network, in which the proteins formed a gel. The formation of the gel provides a model for how proteins aggregate.

In the future, the researchers want to establish whether the behaviour of proteins from peas at the molecular level also takes place on a larger scale. In addition to this they are investigating the interactions of proteins with other food components. It will then be possible to understand how the texture of meat substitute products changes upon heating, and more importantly, it will be possible to predict this in advance.

The research is part of the NWO research programme ’Protein Foods, Environment, Technology and Society’ (Profetas). This programme is examining the possibilities for a fundamental shift in our diet. Researchers from various disciplines are investigating whether the substitution of meat by foodstuffs based on plant proteins is favourable for the environment. They are also investigating whether these changes are technologically and socially feasible.

The research was funded by the Netherlands Organisation for Scientific Research.