Microemulsion-based oil extraction from canola press cake: Applicability of lecithin, Tween 80, and Span 80

The present study aimed to explore the potential of bio-surfactant-based microemulsions (MEs) for extracting canola oil from canola press cake (CPC), a by-product of the oil industry. Lecithin, Tween 20, Tween 80, and Span 80, both with and without co-surfactants, were utilized to formulate ME premixes. The premixes were then combined with CPC at different ratios and subjected to centrifugation. For the Tween formulations, the effects of natural (pH 6.1) and alkaline (pH 10.0) conditions were also examined. Pure lecithin did not extract any oil, but when combined with CPC at a 1:3 ratio (CPC: premix [water:1-propanol: lecithin = 75:20:5 wt%]), approximately 50% of the oil was extracted, mostly in emulsified form. In contrast, using Tween 80 (at 70°C, with a CPC: premix ratio of 1:8 and natural pH), about 27% of residual oil from the CPC was extracted as free oil. Interestingly, under alkaline pH (10.0), Tween: water premix (0.15:99.85 wt%) at a 1:4 premix: CPC ratio resulted in the recovery of 40 – 50% of the oil from the CPC in emulsified form. These findings revealed the potential of the tested surfactants for partial oil extraction from CPC. The effectiveness of very low concentrations of Tweens under alkaline pH requires further investigations.