Application of surfactant aqueous-based solution for oil and phorbol esters extraction from jatropha curcas L. seed-kernel in one step

Jatropha curcas L. oil (JO) derived from both hexane extraction and mechanical screwpressing contains phorbol esters (PEs), which is a suspected carcinogen. This study proposed a JO extraction using mixed surfactant aqueous-based solutions under the appropriate proportion and physical conditions to obtain the highest free oil yield to reduce the PE partition in the oil. The results show that the anionic surfactant enhanced the free oil separation efficiency twofold compared with nonionic surfactant alone. The optimal condition is 1 min of contact time with 13.61 rad s^-1 of orbital shaking and 1 g of the kernel per 10 mL of surfactants solution (30 g-Dehydol LS2, 0.2 g-Alfoterra 145-4PO and 6 g-NaCl in 1 L) which could yield 73% by mass fraction of oil for single extraction. The extracted PEs under that condition is higher in surfactant-rich phase and lower in free oil phase. The mass fraction of extracted PE distributed 53%, 29%, 17% and 1% in surfactant-rich phase, free oil, meal and aqueous phase, respectively. Mixed surfactants solution has ability to extract the oil and PEs in the one-step oil extraction. A half of PEs in the kernel was separated within the surfactant phase. This method is considered a clean technology concept that may be useful for further development and application in the future.