High-purity tri-alpha-linolenin isolation from silkworm pupae oil using sequential simulated moving bed chromatography

Silkworm pupae are a major by-product of the silkworm mulberry industry, and the high content of tri-alpha-linolenin (glyceryl tri-alpha-linolenate, LnLnLn) in silkworm pupae oil makes it an excellent essential fatty acid supplement. However, the complex triglyceride composition of silkworm pupae oil limits its absorption and utilization by the human body. In this study, a sequential simulated moving bed (SSMB) approach for continuous separation was presented to recover the high-value tri-alpha-linolenin monomer from silkworm pupae oil. C₁₈ particles were used as the stationary phase. Acetonitrile and isopropanol were used as the elution mobile phases. Under optimal SSMB conditions, the purity and yield of the extracted products were 95.15±2.06% and 2.14±0.06 mg/mL, respectively. In comparison to the conventional extraction approach, the yield of tri-alpha-linolenin separated by SSMB was 26.7 times greater, the dose of eluent was lowered by 2 times, and the eluent could be recycled. To validate the experimental parameters, a mass transfer diffusion model was used. The molecular diffusion coefficient of tri-alpha-linolenin was 2.61×10⁻⁶ cm²/s, the axial diffusion coefficient was 2.61×10⁻⁶+7.56×10⁻³μ, and the mass transfer diffusion coefficient was 0.87 s⁻¹. The correlation coefficient between the model and the actual measured values was 0.9688. Consequently, the separation of tri-alpha-linolenin monomer in silkworm pupae oil by sequential simulated moving bed chromatography column can be reasonably described and predicted by this model. In conclusion, a novel approach to the commercialization of insect oils was developed by the extraction and purification of tri-alpha-linolenin from silkworm pupae oil using the SSMB approach.