Over the last decade, pea proteins have become common ingredients in plant-based foods, replacing soy proteins. Pea globulins represent a promising alternative, being less allergenic while showing similar structural and mechanical properties. For instance, thermal treatment of highly concentrated pea protein solutions yields firm hydrogels, which can serve as simplified model systems to study plant-based foods. In this work, we extensively investigated the gelation process, probing the in situ structure and dynamics of pea proteins during heating. We integrated quasielastic neutron scattering (QENS), small-angle X-ray scattering (SAXS), and rheology, capturing the multistep process leading to hydrogel formation. QENS enabled real-time observation of the arrest of nanoscale molecular dynamics, while SAXS and rheology provided complementary insight into structural evolution on the nano- and microscale, respectively. Building on this picture of gelation, we then studied how these hydrogels structurally evolve during digestion. Digestion was monitored in situ using small-angle neutron scattering (SANS) within a microfluidic device. Hydrogels were embedded in the chip and exposed to simulated gastric fluid delivered via a microfluidic pump, enabling continuous acquisition of scattering data. This setup was further adapted for synchrotron SAXS and confocal laser scanning microscopy, offering a multiscale view of the digestion process. Our results reveal a two-step collapse of the gel network, in which vicilin, one of the main components of pea globulins, plays a pivotal role. Overall, this study highlights the importance of developing innovative strategies to probe the formation and digestion of plant-based hydrogels, with direct implications for designing more nutritious and safe food products. We hypothesize that controlling the legumin/vicilin ratio in pea protein isolates one can strongly influence the structure and digestibility of the final hydrogel.
Schirone et al. (Sun,) studied this question.