Linear and nonlinear interface rheological behaviors and structural properties of pea protein (vicilin, legumin, albumin)

In the study, the structural properties of PPI and its major component proteins were investigated. The vicilin (7S) showed a more flexible structure, while the legumin (11S) possessed higher hydrophobicity. The albumin (2S) with simple and loose structure presented the weaker interfacial capacity. The difference in the protein structure was responsible for the corresponding protein stabilized interface system. In order to reveal the connection between protein structure and interface rheological properties, the linear and nonlinear rheological behaviors of the formed interface were used to analyze the interfacial microstructure. The results of Lissajous plots showed the proteins of 7S could form an interface with a strain softening behavior in extension. Meanwhile, the 11S tended to form a rigid interfacial layer with the strain hardening. The hydrophobic groups within the protein structure facilitated the formation of the interfacial network structure, leading to an improved emulsifying stability. In contrast, the microstructure of the oil-water interface stabilized by 2S was easy to break, which was consistent with its lower emulsifying activity. The structure-interface properties of the protein adsorption behavior at the oil-water interface could reflect the structural rearrangement at the interface and predict the interfacial microstructure. This research showed the relationship between the stability of protein stabilized emulsion and the protein structure.