Optimization of vegetable oil detachment from oilseed by minimizing interfacial tension

N-hexane has been widely used in vegetable oil extraction industry since it yields high extraction efficiency. However, n-hexane is categorized as a hazardous pollutant due to safety, health, and environmental concerns. Thus an alternative approach for oil extraction method that is free from n-hexane would be worthwhile to develop. In this work, mixed commercial anionic and nonionic surfactants in brine solution were purposed to be used for oil extraction. The results showed a good potential to use as extraction medium in aqueous surfactant-assisted extraction method (ASE). The oil detachment efficiency was exceed 70% for both jatropha and canola oil extraction. In case of canola, the ASE conditions were further modified for maximizing the oil yield. The surfactant concentration, stirring and ultrasonication time, and oilseed to extraction medium ratio significantly impacted the oil detachment and oil extraction efficiency. The effect of extraction temperature was not statistically significant. The triple extraction with three-states reduced the use of extraction medium. The highest oil detachment and oil extraction efficiency were 80% and 60%, respectively. In addition the canola oil from ASE method was found to have a superior oil quality to that of Soxhlet extraction in term of lower acid value and phospholipids content which are the important parameters for the quality of biodiesel feedstock.

正己烷（n-hexane）凭借优异的提取效率，已被广泛应用于植物油提取工业。然而，出于安全、健康与环境保护层面的考量，正己烷被归类为有害污染物，因此开发不含正己烷的新型油脂提取方法具有重要研究价值。本研究拟采用盐水溶液中复配的商用阴离子与非离子表面活性剂用于油脂提取，结果表明该体系作为表面活性剂辅助水相提取法（aqueous surfactant-assisted extraction method, ASE）的提取介质具备良好应用潜力。麻风树与菜籽油的油脂脱除效率均超过70%。针对菜籽油提取，本研究进一步优化了表面活性剂辅助水相提取法的工艺条件以最大化油脂产率：表面活性剂浓度、搅拌与超声时间、油料与提取介质的料液比均对油脂脱除及提取效率具有显著影响，而提取温度的影响未达到统计学显著性。采用三级萃取工艺可降低提取介质的使用量，本研究中最高油脂脱除效率与提取效率分别可达80%与60%。此外，相较于索氏提取法（Soxhlet extraction）所得菜籽油，表面活性剂辅助水相提取法得到的油脂品质更优，其酸值与磷脂含量更低——这两项参数均为生物柴油原料品质的重要评价指标。