Proposed mechanism of formation of solid lipid nanoparticles. Display omitted •A modified PGSS process with expansion into a water stream was developed.•The encapsulation of Vitamin B2 in solid lipid nanoparticles was tested.•Pressure, Vitamin B2 and surfactant concentrations and stabilizer MW were varied.•Best conditions were 15.0MPa, 2% Vitamin B2, 5% SLS and PEG MW of 35kDa.•Best particles had bioactive load of 0.54mg/g and mean particle size of 104nm. Solid lipid nanoparticles (SLN) are spherical particles prepared from solid fats, which can be used as delivery systems by encapsulating bioactives. In this study, particles from gas-saturated solutions (PGSS) were produced by a modified process, using fully hydrogenated canola oil (FHCO) to encapsulate Vitamin B2, a hydrophilic bioactive. Four operating parameters were studied in terms of their influence on encapsulation efficiency, bioactive load and particle size: pressure (10.0–25.0MPa), Vitamin B2 concentration (0.25–2%, w/w), surfactant (sodium lauryl sulfate, SLS) concentration (1–7.5%, w/w) and stabilizer (polyethylene glycol, PEG) molecular weight (2,000–35,000Da). The optimal conditions were determined as 15.0MPa, 2% Vitamin B2, 5% SLS and 35,000Da PEG, resulting in an encapsulation efficiency of 12±0.03%, bioactive load of 0.54±0.05mg/g and bimodal particle size distribution with a main peak at 104±5.7nm, showing that it is possible to generate nano-scale solid lipid particles with a high content of a hydrophilic bioactive; however, further fine tuning is needed.