Pea and lupin protein ingredients are suitable sources to promote the transition to more plant proteins in foods, as they display promising nutritional and emulsifying properties. A deep characterization of the composition of pea and lupin protein isolates and concentrates revealed that they contain 4 to 12 wt.% lipids, with over half being phospholipids. A high-pressure homogenization (HPH) treatment was applied to their aqueous suspension. It altered the aggregated state of their proteins and improved protein solubility1. Oil-in-water emulsions (10 wt.% oil, 2.5 g proteins/L) were prepared by HPH to obtain droplets around 2.5 µm. Emulsions formulated with protein isolates led to droplet flocs about five times larger than in emulsions prepared with concentrates. These results, supported by microscopic investigations, suggest extensive bridging by protein aggregates present at the droplet surface. The digestive fate of emulsions was examined using in vitro static model (pH-Stat) to elucidate how the microstructure and interfacial composition influenced lipid digestibility and bioavailability. Lipolysis was evaluated through lipid class analysis via HPLC. During the oral phase, the microstructure of the emulsions prepared with protein isolates was altered, as the introduction of α-amylase led to the loss of the proteinaceous network bridging the droplets, without inducing coalescence. Comparable values of lipolysis were reached at the end of the gastric phase (from 12.3 to 17.3 % mol/total mol), and after the intestinal phase (from 67.1 to 72.9 % mol/total mol). However, lipid bioavailability varied depending on the protein source, with approximately 85 wt.% of absorbable lipids measured for pea protein-based emulsions, against 49 to 63 wt.% for lupin protein isolate- and concentrate-based ones, respectively. These first results suggest a marked role of endogenous phospholipids, and potentially of other non-proteinaceous components present in plant-based ingredients, on the nutritional fate of the emulsions. To investigate this hypothesis further, a new series of emulsions (with higher protein-to-oil ratio) were formulated to amplify the competition between proteins and phospholipids for interfacial adsorption. Further characterization was conducted by transmission electron microscopy to gain deeper insights into the interfacial composition of the emulsions. Selected ones were submitted to digestion using in vitro static (pH-Stat). This work offers comprehensive insights regarding the incorporation of plant protein ingredients into formulated foods. While food systems lean towards plant-based innovations, understanding how the composition of these ingredients affects their processing and nutritional properties from a perspective of usually overlooked endogenous components can help to rationalize the formulation of sustainable and nutritious foods.