Dry and Aqueous 2-Methyloxolane as Green Solvents for Simultaneous Production of Soybean Oil and Defatted Meal

Abstract

Edible oils are currently largely obtained by solvent extraction using hexane. Despite the fact that this petroleum solvent is known to be neurotoxic, hexane extraction remains the accepted standard process for seed oil extraction and particularly, but not exclusively, for soybean oil extraction. This study evaluates an alternative replacement of hexane with a bio-based and safe solvent, 2-methyloxolane (2-MeOx), either in its dry or in its water-saturated (4.5%w) aqueous form, referred to as 2-MeOx 95.5% in this paper. The analyses focused on extraction yields, composition, and quality of the extraction products. This study also evaluates the feasibility to substitute hexane in industrial extraction processes. Therefore, a kinetic study and multistage cross-current extractions were performed. The work concluded that both 2-MeOx and 2-MeOx 95.5% are good candidates to replace hexane in industrial processes for the extraction of soybean oil, as they gave similar compositions for oil and defatted meal. Hexane and 2-MeOx also gave similar results in terms of extraction rate and performances. 2-MeOx 95.5% exhibited a slightly different behavior during extraction, which was attributed to water diffusion from the solvent to the solid matrix due to its high water activity.