<p>This study evaluated the synergistic effect of ultrasound pretreatment and insoluble solids removal on the fermentation of pea protein concentrate (<i>Pisum sativum</i> L.) by <i>Lactobacillus gasseri</i> and its implications for the kinetic, fermentative, and rheological properties of the system. Four experimental treatments were investigated: protein fermented by <i>L. gasseri</i> (P-LG), protein pretreated by ultrasound and fermented by <i>L. gasseri</i> (P-US-LG), soluble protein fermented by <i>L. gasseri</i> (S-LG), and soluble protein pretreated by ultrasound and fermented by <i>L. gasseri</i> (S-US-LG). The growth kinetics, based on total cell counts determined in a Neubauer chamber, was modeled using a modified Gompertz equation for the growth phase, whereas the post-peak phase was described only descriptively with an exponential decay function. Acidification was modeled using a four-parameter logistic equation. The rheological properties were evaluated using flow and oscillatory testing, with shear-sweep data fitted to the Ostwald-de Waele model. The results indicated that the removal of insoluble solids was associated with higher <i>µ</i>_<i>max</i> values and a shorter time to reach pH &lt; 5.5, characterizing faster acidification in kinetic terms, while ultrasound modulated the microbial adaptation time in a manner dependent on the protein fraction. The non-centrifuged systems showed greater consistency and predominantly elastic viscoelastic behavior, while the soluble fractions exhibited lower viscosity and less organized structures. Radar visualization highlighted the distinct functional profiles among treatments. Taken together, the findings demonstrate that combined strategies of physical processing and lactic fermentation enable modulation of the techno functional properties of fermented plant proteins.</p>