Extensional Rheology of Protein-Polysaccharide Mixtures

Many food formulations that replace animal-based proteins with vegan, plant-sourced proteins contain polysaccharides as rheology modifiers which influence ropiness, stringiness and dispensing behavior. It is becoming increasingly recognized that properties associated with heuristic terms like stringiness, stretchiness, or ropiness are correlated with the extensional rheology of these formulations. However, quantitative measurements of macromolecular responses to streamwise velocity gradients for these complex systems has been a longstanding challenge. In this talk, we characterize the pinching dynamics and extensional rheology of different mixtures of proteins and polysaccharides found in several vegan food foams and emulsions via dripping-onto-substrate (DoS) rheometry. We elucidate how complexation transforms the perceived stringiness and responses to both shear and extensional deformations.