Abstract
The goal of this work was to develop a one-pot strategy for the fabrication and impregnation of starch aerogels with green coffee oil (GCO) in supercritical carbon dioxide (scCO2). For that purpose, different modifications were made to the production process to improve the integration of the three essential steps of aerogel fabrication. A strategy based on supercritical extraction (SCE) was proposed to address the conventional drying process, as well as the utilization of CO2 during the aerogel fabrication steps. The development of a novel drying approach was the most challenging task of this work as it should be performed without any solvent-exchange step. The results show that aerogels with high surface area (95 m2.g-1) could be produced using a continuous flow of CO2/ethanol (20 MPa, 40 °C, 2 mL.min-1 CO2 with 11% v/v ethanol). The next step comprised the formation of aerogels in the presence of CO2. The optimal surface area was 185 m2.g-1. Finally, the integration of all the above steps was achieved, and gelatinization, retrogradation, and drying happened sequentially in the same vessel under CO2 atmosphere. This one-pot fabrication was followed by the impregnation with GCO using a high-pressure injection step. An impregnation efficiency of 24% was obtained with this one-pot strategy confirming that a fully integrated process for the fabrication and impregnation of starch aerogels could be attained.
