Towards more sustainable surimi gels: Deciphering the hybrid gelation of myofibrillar/plant proteins

The effect of substituting myofibrillar protein by plant protein (wheat, soy, rice, and pea protein) on gelling properties of hybrid surimi/plant protein (HSP) gels was investigated. The optical, confocal laser scanning microscope (CLSM), and scanning electron microscope (SEM) observations showed phase separation occurred as the substitution ratio increased up to 30%, and the legume proteins had better compatibility to surimi, with the tighter and more uniform structure of the corresponding hybrid gels. The diverse hydrophobicity that existed between the cereal and legume proteins affected the conformation and thermal aggregation of myosin revealed by differential scanning calorimetry (DSC) and dynamic rheological measurement. No subunit-level cross-linking between the myofibrillar proteins and plant proteins was found as evidenced by electrophoresis. Hydrophobic interactions, disulfide bonds, and β-sheet content were more abundant in mixed gels of pea protein. Dynamic light scattering (DLS) found that the mixed gels of legume proteins were of less oversized aggregates. Small angle X-ray scattering (SAXS) could be a potential method to monitor the internal phase behavior of the HSP gels by distinguishing the sea-island and interpenetrating structure. In summary, myofibrillar-plant protein interactions probably due to hydration were vital for the formation of the hybrid gels via altering the competitive rate of gelation and phase separation.