Semi-continuous process for rapid recovery of intact oleosomes via thermally accelerated swelling: Overcoming the activation energy barrier for seed imbibition

Soaking is a critical rate-limiting step in the recovery of intact oleosomes. This study establishes a thermodynamic basis for optimising sunflower seed hydration to enable a continuous, rapid extrusion-juicing process to recover oleosomes. By investigating water uptake kinetics from 4 to 70 °C, a high activation energy barrier for hydration was identified. It was demonstrated that soaking at 50 °C for 1 h provides sufficient thermal energy to trigger a glass-to-rubbery transition in the seed matrix, achieving maximum turgor while bypassing the prolonged leaching phase associated with conventional, widely used methods (4 °C for 16 h). This new soaking regime reduces the process time by 93% without compromising the oleosome integrity (micron-sized droplets) or protein composition (oleosins, as the major oleosome-associated proteins, preserved). Although the semi-continuous extrusion yield was slightly lower than batch blending due to the absence of a solvent phase, the process throughput is significantly enhanced. In addition, emulsions made from the new soaking method cream showed better stability (compared to the conventional soaking regime) in terms of oleosome average diameter and turbidity stability index after 14 days of storage at 20 °C. This work presents a fast and scalable protocol for the industrial recovery of oleosomes.