​Calcium caseinate (a micellar dairy protein) forms fibrous structures, which are a promising material for next-generation meat analogues. Better insights into the formation of these fibrous structures provides valuable insight for developing these, and plant-based, meat analogues. Fibre formation has been shown to be strongly influenced by whether the solvent is hydrogen or deuterium based water, suggesting the protein-water interactions are dominated by a subtle solvent effect. The structure of the fibrous materials also depends on the powderisation method, with spray drying and roller drying producing different fibre structures.

This investigation used quasi-elastic neutron scattering on IRIS to reveal the structuring potential of spray dried and roller dried food powders both when dry, and when solvated with H2O and D2O. The researchers found that the drying method did influence the protein dynamics. As roller drying involves more intense heating of the calcium caseinate, it allows the proteins to arrange into a more thermodynamically stable formation, making the material less susceptible for fibre formation.

The deuteration experiments disclosed the large impact caused by changing the solvent. Whereas the H2O solvated fibres formed intact and homogenous gels, the use of D2O resulted in a paste with an inconsistent texture. The neutron studies support these observations by revealing a clear difference in dynamics. The difference is not limited to the external hydrophilic protein groups of the protein, but also extends to the internal hydrophobic groups. Consequently, this work establishes a clear correlation between the microscopic protein dynamics and the bulk fibre structure formation, providing insight into the formulation of new meat replacement processing methods.

Instrument: IRIS