Innovative bioaerogel-like materials from fresh-cut salad waste via supercritical-CO2-drying

Fresh-cut salad waste was dried by means of supercritical carbon dioxide technology using ethanol as co-solvent. The obtained material was characterized by a white color and a brittle texture. Microscopic images revealed an aerated structure, with well-evident intra and inter-cellular spaces. Based on the high internal surface (> 100m2/g), the extremely low density (< 0.5 g/cm3) and the high porosity (> 80%), supercritical-dried salad waste can be regarded as a bioaerogel-like material. One gram of this material absorbed 33 and 19 g of water and oil respectively. Industrial application: Fresh-cut processing of salad generates large amounts of solid waste which is not suitable for conversion into biogas or fertilizers. This waste poses management issues for producers and represents an environmental burden. Fresh-cut salad waste could be valorized to produce bioaerogel-like materials with enhanced solvent uptake ability, to be exploited as food ingredients, packaging, absorbents or innovative carriers for both lipophilic and hydrophilic compounds.