Phenomenological modeling and intensification of texturing/grinding-assisted solvent oil extraction: case of date seeds (Phoenix dactylifera L.)

Accelerated Solvent Extraction (ASE) and Dynamic Maceration (DM) were used with nhexane to study the extraction of oil from date seed powders with different particle sizes. The intensification was studied with instant controlled pressure drop (DIC) as texturing pretreatment. DM yields increased from 4.57% to 10.49 +/- 0.05% dry-dry basis (ddb) when particle size decreased from 1.4 to 0.2 mm. For coarsely grounded seed powder, ASE oil yields were 11.35 +/- 0.05% ddb and 14.15% ddb for untreated and DIC date-seeds, respectively. Optimized DIC pretreatment allowed the smallest particle size powder to get 15.2 +/- 0.05% ddb as ASE yields, while the 2-h DM yields increased from 4.67 to 11.62 +/- 0.05% ddb for particle size decreased from 1.4 to 0.2 mm, respectively. Fundamental analysis of various powders was achieved through washing-diffusion phenomenological model. DIC texturing implied higher washing stage, with relative starting accessibility %dYs of 70% against 55% for untreated particles. Consequently, the diffusion stage time was dramatically reduced, without great modification of effective diffusivity D-eff value. Therefore, DIC ground seeds greatly enhanced the mass transfer mechanism. The evaluation of starting accessibility delta Y-s enables to establish an empirical relationship between dYs and particle diameter delta Y-s=f(D). Finally, DIC texturing did not imply any modification of the lipid profile. (C) 2015 The Authors. Published by Elsevier B.V. on behalf of King Saud University.