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Explora: Environment
and Resource Microemulsion-based canola oil extraction

oleosomes but still attached to particle surfaces is extraction of residual oil of canola press cake (CPC) are
commercially recovered using organic solvents such explored. The readers are referred to the most recent
as hexane. Nevertheless, due to environmental and comprehensive reviews for further details. 7,11
6
health-related issues associated with organic solvents, According to existing reports, lecithin has been
the oil industry is actively seeking greener, more successfully utilized for microemulsification of canola
environmentally friendly substitutes. One promising oil (up to 90%), where increasing the temperature or the
alternative is the surfactant-assisted aqueous extraction lecithin-to-co-surfactant ratio increased the mono-phase
and/or microemulsion (ME) technique. 7 ME region (Winsor IV ME). Under optimal extraction
MEs are colloidal systems that typically contain water, conditions, up to 82% of canola seed oil was recovered.
oil, surfactants, and sometimes other components, such It needs to be highlighted that these investigations were
as salts, solvents, co-surfactants, and co-solvents, mixed conducted on canola seed meal (CSM) using partially
in specific proportions. The interfacial tension of MEs purified lecithin. 13,14 The simultaneous microemulsification
is generally ultra-low (i.e., 0.01 – 0.0001 mN/m), which and extraction of lutein and lycopene using lecithin as the
gives them strong emulsification and high solubilization natural surfactant have also been explored. 7
capacities. Depending on their fluidity, MEs can easily The capability of Tween 80 in the presence of
penetrate solid surfaces through capillary pores, allowing co-surfactants, at various ratios, for microemulsification
them to solubilize, disperse, or remove attached oils of bee propolis, kerosene, and hexane has been
upon contact with a substrate. 7-10 While the mechanisms investigated. 15,16 Gossypol, a toxic bio-compound, has also
for extracting or recovering oil and other hydrophobic been removed from cottonseed using a Tween 80-based
components from various matrices using MEs are not yet ME system. The potential of Tween 80 for recovering
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fully understood, current reports (primarily non-food residual oil from palm-pressed mesocarp has also been
applications) suggest that oil removal from matrices can be recently evaluated. A 1:1 mixture (hydrophilic-lipophilic
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achieved through three mechanisms: roll-up or roll-back, balance = 9.7, 0.1%) of Tween 80 and Span 80 increased
snap-off, and diffusion or micellar solubilization. 7 oil yield recovery from condensed corn distillers’ soluble
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Considering the crucial role of surfactants in the by 5 – 10%. Furthermore, the potential of different
creation of MEs, the selection of surfactants is critical ratios of Tween 80:Span 80 and various co-surfactants for
due to their effects on formulation, functionality, microemulsification of krill oil and isopropyl myristate has
20
and even the gastrointestinal fate of MEs. Two major been examined. The demulsifying capabilities of Tweens
concerns that should be concurrently considered are (20 and 80) and Spans (20 and 80) for walnut and peanut
efficacy and safety, especially when the surfactant is oil recovery have been reported. 21-23 According to these
intended for use in an ME system that will eventually studies, Tweens were able to demulsify, but only Tween
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be consumed by humans. 7,11 In addition to natural 20 (at 1.2% and pH 9.5) recovered 72% of peanut oil.
surfactants, food-grade synthetic surfactants and non- Recently, under optimal conditions (1:10 seed: water ratio,
food-grade extended surfactants have also demonstrated 1.4% [wt%] Tween 20, pH 12.0), over 50% of rapeseed oil
their abilities to facilitate microemulsification. However, was successfully extracted. 24
synthetic and extended surfactants may not be suitable As described, the residual oil of oil-bearing plants is
for food applications, particularly if concerns such as currently mainly recovered by hexane, which presents
irritability, toxicity, or environmental impact arise. 5,12 environmental and health-related issues. Therefore,
Consequently, there is an increasing demand for bio- the edible oil industry is actively seeking alternative
based surfactants, and over the past two decades, techniques. In this regard, the surfactant-assisted
researchers have endeavored to study and improve the aqueous extraction technique, particularly with the
applicability of bio-based or biodegradable surfactants extended surfactants (with toxicity concerns), is one of
in ME formulations. However, the inherent functional the promising alternatives that has shown high efficiency.
limitations and high cost of bio-based surfactants, However, there are very limited reports on the application
compared to synthetic ones, remain significant of food-grade surfactants for oil recovery from oil-bearing
challenges. The commercial applicability of bio-based plants, particularly for extracting residual oil from
surfactants for plant oil extraction is also limited due mechanically pressed cakes. Therefore, the present study
to the structural complexity of triglycerides. Lecithin aims to evaluate the abilities of lecithin (both partially
and Tweens/Spans are well-known examples of natural purified and pure), Tween 80, and Span 80, with and
and synthetic biodegradable surfactants, and in the without co-surfactants, for recovering residual oil from
present study, their capabilities in the liberation and CPC under various processing conditions.

Volume 2 Issue 2 (2025) 2 doi: 10.36922/eer.6562