Innovative technological approach in the production of seed oils [Approccio tecnologico innovativo nella produzione degli oli di semi]

Industrial processes for the extraction of edible oil from oleaginous crops generally involve a solvent extraction step, which may or may not be preceded by pressing or other physical methods of separation (centrifugation, Sinolea (R) system). Solvent-based (commercial hexane) processes achieve oil yields in excess of 95% with residual oil in defatted meals less than 1%. Safety implications surrounding the use of hexane prompted attempts to develop processes based on the use of aqueous extraction media or other biorenewable solvents (aqueous ethanol, supercritical carbon dioxide). These environmentally clean technologies, however, have significant challenges that have limited their commercial applications: (1) lower efficiency of oil extraction, (2) demulsification requirements to recover oil from oil-rich emulsion fraction stabilized by proteins and phospholipids, (3) treatment of the resulting aqueous effluent. This article analyzes published information on aqueous extraction processes and highlights the main limitations to the development of these technologies. It also briefly reports on some preliminary results of a study on the characteristics of hazelnut oils obtained with different physical systems: technology type and process conditions may lead to results not always easily predictable