Utilization of pulse protein-xanthan gum complexes for foam stabilization: The effect of protein concentrate and isolate at various pH

The present study examines the foaming behavior of pea and faba bean protein concentrates and isolates and explores the impact of pH and protein-polysaccharide complexation on overrun and foam stability. Foams were prepared with 5 wt% proteins with and without 0.25 wt% xanthan gum (XG) at pH 3, 5, 7 and 9. Most foams were unstable without XG. With XG foaming properties of protein concentrates were better than isolates. Irrespective of protein type and content, all protein-XG foams at pH 3 destabilized due to large insoluble complexes, however, at pH 5 foams were stable due to smaller size of insoluble complexes. Both the protein concentrate-XG foams were stable at pH 7 and 9 due to optimum viscosity and surface tension of the soluble complexes. Overall, the study revealed that the overrun and stability of pulse protein foams can be significantly improved by adding XG and controlling their intermolecular interactions as a function of pH.