Oil recovery in rosehip seeds from food plant waste products using supercritical CO2 extraction

Valuable oils in rosehip seeds produced as the solid waste during the process of marmalade production using seed-containing fruits were recovered by supercritical CO2 extraction method. The influence of the particle size (125 <= Dp > 1000 mu m), volumetric flow rate of supercritical solvent (0.75-3.5 mL/min), pressure (20-40 MPa), temperature (40-60 degrees C) and entrainer concentration (2.5-7.5%vol. ethanol) on the extraction yield in the recovery process was examined. The highest extraction yield determined as 16.5 g oil/100 g dry solid was reached in approximately 150 min by using supercritical CO2 extraction (30 MPa, 40 degrees C, 0.75 mL/min, 355 < Dp < 500 mu m) and in the case where 5%vol. ethanol is used as entrainer, it was reached in about 90 min. In similar oil profiles obtained through Soxhlet and supercritical fluid extractions, the ratio of unsaturated fatty acids to saturated fatty acids is about 17. Significant changes were determined in morphological structures of waste seeds compared to unprocessed seeds in marmalade production, by using scanning electron microscope. Apparent solubility values of rosehip oil in supercritical CO2 did exhibit a significant consistency with Chrastil, del Valle-Aguilera, Adachi-Lu and Sparks solubility models. (C) 2016 Elsevier B.V. All rights reserved.