Production of stabilized sub-micrometric particles of carotenoids using supercritical fluid extraction of emulsions

Sub-micrometer particles of carotenoids (β-carotene and lycopene) suspended in aqueous media were produced by extraction of the organic solvent from the droplets of an oil-in-water emulsion with supercritical CO2. The influence of the process parameters emulsion flow rate, concentration of surfactant/carrier material and pressure on product characteristics was evaluated. Suspensions containing stabilized carotenoids with final particle size of 344–366 nm, encapsulation efficiency of 34–89% and degree of isomerization from carotenoid trans to cis forms in the range of 0.02–15%, were obtained. Independently of the type of carotenoid used, emulsion flow rate influenced the production of suspensions of carotenoids, particularly the encapsulation efficiency and the degree of isomerization. Higher encapsulation efficiencies, but also higher degradations were obtained when β-carotene was employed instead of lycopene. The concentration of surfactant/carrier material was the only process parameter that influenced the final particle size, while the encapsulation efficiency and degree of isomerization were influenced also by the concentration of surfactant/carrier material and by pressure.