Protein extraction from lupin seeds: a mathematical model

The effect of particle size and microstructural modification on protein extraction from defatted lupin was studied. Particles of different sizes (128–1425 μm) from untreated (control), flaked and exploded samples were extracted at pH 8.0–8.5 and different temperatures. A three-parameter kinetic model as well as a diffusional model were fitted to data. The yield of protein from the surface of particles, and the total extracted protein yield increased as particle size decreased, while the first order rate constant increased slightly or remained constant. Diffusion coefficients varied between 0.5 and 4.5x10⁻¹² m² s⁻¹ and were higher in exploded and flaked material than in the control. The energy of activation for diffusion was 43 kJ mol⁻¹. Differences in microstructure were studied by scanning electron microscopy.