Influence of Formulation pH and Ionic Strength on the Techno-Functional Behaviour of Legume Grass Protein Concentrates Obtained by Gentle Membrane Separation

Abstract Integrating new plant protein ingredients into formulated foods requires understanding how they behave under complex conditions such as variations in pH, ionic strength, and interactions with other components. These factors directly influence functional properties that determine their success in diverse applications, from beverages and baked goods to meat analogues and aerated products. This study investigated RuBisCO-rich legume grass concentrates (LGCs) produced through a gentle, industrially scalable membrane filtration process coupled with spray-drying. The work aimed to characterise their physicochemical and functional behaviour under realistic commercial formulations, including the combination of two pH levels (4 and 7) and two ionic strengths (0.02 M and 0.2 M NaCl). Two drying conditions (lab and pilot-scale) were also compared to assess their influence on ingredient properties. While the drying process affected hydrophobicity and particle size, these changes did not significantly alter functional performance. Instead, pH was the dominant factor: foaming stability improved under acidic conditions, while gel strength and gelling capacity were higher at neutral pH. Ionic strength had a minor yet positive effect on solubility and gel firmness. Overall, the results highlight the versatility of LGCs as sustainable protein ingredients suitable for a wide range of plant-based food applications.