Gelling properties of mixed β-lactoglobulin/pea proteins systems: Demystifying the role of the 7S/11S globulin ratio

Pea protein isolates (PPI) are the main studied pulse protein ingredients due to the high consumer demand for alternative and sustainable plant-based products. However, PPIs have limited applications in the formulations of food products due to their low gelling properties. Controlling the 7S/11S ratio has been identified as a key parameter for enhancing the gelling properties. Moreover, the use of mixed protein systems composed of PPI and β-lactoglobulin (β-lg) also represents an interesting strategy to enhance gelling properties when compared to the exclusive use of PPI. However, the combination of these two parameters (7S/11S ratio and β-lg incorporation) has never been explored.

Consequently, this study aimed to 1) determine optimal 7S/11S ratios and 2) identify the interactions involved in the gelation of mixed systems composed of β-lg/pea proteins. Mixed protein systems with different 7S/11S and β-lg/pea proteins ratios underwent thermal gelation in a rheometer, with subsequent measurement of gel stiffness (G’). The 7S/11S ratios that yielded maximal G’ were then subjected to further analysis through solubilization in various bond-specific disruptive agents followed by SDS-PAGE electrophoresis to identify the interactions and proteins involved during thermal gelation.

Results showed that a 7S/11S ratio of 0.5 promoted the formation of firmer gels in the presence of β-lg. Gels were primarily formed via disulfide bonds with β-lg, 11S legumin, as well as 2S albumin being the main proteins involved. In the absence of β-lg, gels with a 7S/11S ratio exceeding 1.89 exhibited increased firmness, as gelation was predominantly directed by the formation of hydrophobic interactions by 7S vicilin and 2S albumin.

Our findings provide a comprehensive understanding of how varying 7S/11S ratios impact the firmness of β-lg/pea proteins gels, along with the underlying interactions involved during thermal gelation. Ultimately, this knowledge could contribute to enhancing the gelling properties of pea proteins in mixed systems.