Comparative Assessment of Thermal Aggregation of Whey, Potato, and Pea Protein under Shear Stress for Microparticulation

The presented work investigates the aggregation behavior of whey, pea, and potato proteins under a shear stress using a rotational rheometer. The size, protein interaction, and morphology of the aggregates were analyzed. Whey protein particles were cross-linked by disulfide bonds (75%-90%). In contrast, potato protein particles were cross-linked by a hydrophobic interaction (88%-97%). High shear rates were needed to limit the aggregate growth. Pea protein particles were stabilized in equal parts by hydrophobic interactions (40%-62%) and disulfide bonds (37%-56%) in equal parts. Aggregate size was dependent on the processing history of the protein. Native pea protein favored a particle size of 5-30 μm and was independent of the shear rate. An increasing shear rate decreased the aggregate size of preaggregated pea protein to a d₅₀ of 29 μm. A general prediction of the protein aggregation behavior based on the molecular structure remains a challenging task. This research provides insights into the aggregation behavior of pea and potato proteins and helps to design microarticulated structures of plant proteins.