From protein-dense droplets to functional ingredients : designing scalable plant protein particles through phase separation

The rising demand for sustainable, plant-based proteins calls for ingredients that are both functional and scalable. Conventional legume protein ingredients often exhibit poor dispersibility, high viscosity, and uncontrolled aggregation, limiting their use in high-protein food systems. This thesis investigates liquid–liquid phase separation (LLPS) as a biomimetic and underutilised route to design protein-dense droplets that can be transformed into colloidal protein particles with consistent structure and functionality. Using legume proteins, such as pea, fava, and soy, as model systems, we establish the physicochemical conditions that govern LLPS and demonstrate its robustness in both purified fractions and commercial flours. The droplets are stabilised through mild heat treatment and subsequently converted into powders via spray drying. The resulting colloidal concentrates and isolates exhibit improved dispersibility, wettability, and low-viscosity rehydration, distinguishing them from conventional protein concentrates and isolates.

A central aspect of this work is its compatibility with scale-compliant processing: the LLPS-based route integrates with existing wet extraction workflows without requiring specialised equipment. By addressing persistent challenges such as batch variability and poor hydration performance, this research provides a clean-label, structure-led alternative to purity-driven extraction. Altogether, the thesis bridges fundamental insights from food physics with applied ingredient technology, offering a scalable strategy to produce next-generation plant-protein ingredients. These outcomes contribute to the development of sustainable, high-protein foods and support the broader transition toward circular, plant-based food systems.