The effects of both preparation method and season on the supercritical extraction of ginger

Abstract

Experiments were conducted to study and compare the supercritical extraction of oleoresin from fresh, oven-dried and freeze-dried ginger samples. When new season water-rich fresh ginger rhizomes were utilised, higher extraction yields resulted relative to both the oven-dried and freeze-dried samples. Mathematical modelling of experimental data confirmed that this yield enhancement resulted principally from an enhancement in the effective diffusivity within the ginger particle. However, when a more fibrous and less moist old season ginger supply was utilised, the mass transfer rate in all samples declined. Further, the reduction in effective diffusivity was most pronounced for the fresh ginge..