Aqueous Extended‐Surfactant Based Method for Vegetable Oil Extraction: Proof of Concept

Abstract

AbstractThe use of hexane to extract vegetable oil from oilseeds is of growing concern due to hexane's environmental impact and because of worker exposure concerns. The goal of our work is to demonstrate that the aqueous extended‐surfactant‐based method is a viable alternative for vegetable oil extraction. In our method, ground oilseeds were dispersed in the aqueous surfactant solution, allowing the oil to be liberated from the seeds as a separate phase from the aqueous phase. The impact of pH, shaking intensity, shaking time and seed to liquid ratio on oil yield are presented. Extended‐surfactants are a new type of surfactant with propoxylate (PO) and/or ethoxylate (EO) groups inserted between the hydrophilic head and the hydrophobic alkyl chain of the surfactant molecule. This unique structure of extended‐surfactants enables them to produce ultralow interfacial tension with vegetable oils. We have found that at low aqueous concentrations (less than 0.3 wt%), extended‐surfactant solutions are able to produce ultralow interfacial tension between aqueous extraction and vegetable oil phases. At optimum condition (seed to liquid ratio of 1–5, 30 min extraction at 150 shakes/min and 30 min centrifugation at 2,170×g) we achieved 93–95% extraction efficiency for peanut and canola oils at 25 °C. The oil quality produced from the aqueous extended‐surfactant‐based method was found to be comparable or even superior to that obtained from hexane‐based extraction, further demonstrating the viability of aqueous extended‐surfactant based extraction.