Structuring protein networks for applications in meat alternatives

The development of more efficient protein networks with well-defined pore structures and anisotropy is essential for creating plant-based fibrous meat analogues with improved juiciness and an overall increased consumer acceptance. Achieving these structural features requires a deep understanding of how proteins aggregate and organize under processing conditions, such as shear. In this project, we aim to gain particle-scale insights into the gelation and structuring processes of proteins under shear by using model protein systems. Our previous work demonstrated that, under weakly attractive forces, gelation proceeds via a nonequilibrium percolation process. Building on these findings, we now focus on designing model protein particles from various plant-based sources to visualize and compare their aggregation behaviors. To achieve this, we use these spherical,
micron-sized protein aggregates as models for primary aggregates. Using a confocal microscope equipped with a rheometer head, we can impose controlled shear flow while directly imaging the evolving structures. This approach enables us to distinguish two distinct regimes: (i) Weak attraction near the isoelectric point where we find fractal aggregates, and (ii) high repulsion, far above the isoelectric point, where shear overtakes this repulsive barrier and forms dense,
slab-like structures. By applying particle tracking techniques, we analyze the dynamics of structure formation in detail. Fine-tuning interaction parameters, such as attraction, shear rate and volume fraction allows us to understand this mechanism and create optimized anisotropic structures that enhance juiciness and mouthfeel. Furthermore, by integrating both bulk rheology and microrheology, we investigate both the overall and local rheological response, respectively, providing a comprehensive picture of how particle-scale interactions translate into macroscopic properties.
This work is conducted in collaboration with bulk rheology studies on actual meat alternatives at Wageningen University, which extend our observations to larger length scales. Ultimately, these structural and rheological insights will be linked to sensory studies which are also carried out at Wageningen University, enabling us to determine design principles for creating the next-generation, juicier plant-based meat alternatives.