In this study, novel high protein biopolymeric melts were quantified by extrusion inline rheological measurements and the microstructure of the extrudates was characterized with optical microscopy. The raw ingredients, i.e. feed composition, used consisted of ternary protein mixtures, i.e. oat, wheat and potato proteins, together with potato starch and potato fibers mixed in different combinations. The rheological response of the high protein vegetable mixtures showed shear thinning behavior independent of the feed composition and moisture content in the range of shear rates investigated. The experimental data fitted well with power law model and the variation of the model parameters was interpreted based on the feed composition and resulting microstructure of the extrudates. Microstructural investigations revealed protein and fibre agglomerates while starch formed a continuous phase.