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Explora: Environment
and Resource Microemulsion-based canola oil extraction

total oil content of each set of experiments was analyzed, Given the importance of moisture content in the CPC,
and the oil extraction rate was calculated based on the oil this parameter was also measured. The average moisture
content of the corresponding batch. It is important to note content (based on at least three replications) was 6.4%.
that each measurement was repeated at least 3 times, and According to industrial regulations, the moisture content
the average of the replicates was reported. of seeds must be ≤6%, or they must be dried before further
processing. 6,27
3. Results and discussion
Regarding the oil content of the CPC, it contained
3.1. Chemical and physical characteristics of CPC 15.8 ± 0.3 wt% of oil. It is noteworthy that the initial oil
The CPC consisted of large lumps (several inches) with a content of the canola seeds was 42.2 ± 0.4 wt%. During
very compact but porous structure (Figure 2). To reduce the oil extraction process in the industry, part of the
the size of the lumps, they were manually crushed using CSM oil (~50 – 80%, depending on the efficiency of the
a mortar and pestle and passed through a nest of sieves to mechanical expeller) is extracted as intact oil. Therefore,
evaluate their particle sizes. As shown in Table 1 (Section only 20 – 50% of the oil that remains in the CPC needs
6
A), the CPC contained a wide range of particles; however, to be extracted using organic solvents or alternative
only 19.7% of the particles were smaller than 420 μm. It is techniques, including the ME technique. In the case of our
well documented that the smaller the particles, the higher samples, approximately 62% of the CSM oil was already
the oil extraction yield due to the increased surface area extracted (the CSM oil content was 42.2%, whereas the
and better accessibility of disrupted cells on the particle oil remaining in the CPC was 15.8%). Therefore, the CPC
surface. 6,13,24,26 However, as indicated, only a small fraction contained only 38% of the initial oil content of CSM, which
of the CPC particles fell within the size range typically required further extraction.
recommended for oil extraction (<500 μm, or more strictly Based on the nitrogen content of the samples and using
<200 μm). These findings (Section B in Table 1) also showed the generally accepted protein conversion coefficient (i.e.,
that the mass mean diameter of the CPC was ~1,150 μm. 6.25), the protein content of the CPC was around 38%.
It is likely that conventional size reduction processes could It is worth noting that this conversion coefficient may be
reduce the size of CPC particles to a reasonably lower range high, and it is believed that the actual value for most foods
(<500 μm), potentially improving the oil extraction yield. should be between 5.1 and 6.0. The CPC also contained
Nevertheless, as the main aim of the present study was to sugars (mostly insoluble polysaccharides such as cellulose,
evaluate the capability of surfactant-assisted systems, the hemicellulose, and lignin) and minerals, but these were
CPC, as a whole, was used and tested. not determined. Knowing the content of these parameters
is important, as the protein or polysaccharide content of
the pellets may vary depending on different treatments
(e.g., acidification and alkalization) or extraction conditions.

3.2. Efficacy of lecithin-based ME systems
To understand the overall capability of partially purified
lecithin (Epikuron 135F) in canola oil extraction,
preliminary tests were conducted on CSM. It is noteworthy
that the oil content of CSM was much higher than that of
CPC (i.e., ~42% vs. ~16%). CSM was initially mixed with
a premix containing different proportions of 1-propanol,
lecithin, and water (Table 2). The mixtures were then
Figure 1. Schematic representation of the different phases (right) and heated (60°C, 30 min, with one set of identical formulations
forms of oil (left) after centrifugation of CPC: premix mixtures
Notes: CPC = Canola press cake; Premix = Mixture of 1-propanol, not heated), cooled (~25°C), and centrifuged (10,000 g for
lecithin, and water. 10 min). Based on visual observations, heating was crucial.

Figure 2. Visual comparison of canola press cake and its mass fraction distribution. Mass retained on meshes #10, #18, #30, #40, and #500 (from top to
bottom and left to right).

Volume 2 Issue 2 (2025) 4 doi: 10.36922/eer.6562