Page 124 - EER-2-2

Explora: Environment
and Resource Microemulsion-based canola oil extraction

2. Materials and methods co-surfactant at different ratios (80:20, 70:30, 67:33,
60:40, 50:50, and 40:60 w/w). Due to the low solubility of
2.1. Chemicals Epikuron 170 in 1-propanol, the mixtures were vigorously
The CPC was collected from a vegetable oil extraction agitated and mildly heated to ensure thorough dissolution.
facility and kept frozen (−18°C) before analysis or The surfactant: co-surfactant mixture was considered a
extraction. Briefly, in the oil extraction facility, canola portion (X). It was then mixed with water (Y) at various
seeds were cleaned, cracked, and flaked using a roller- X: Y ratios (10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30,
type flaker (clearance between rolling drums: 3 mm). 80:20, and 90:10 w/w) in 50 mL screw-capped conical
The seeds were then cooked (95 – 100°C, 45 – 60 min) tubes. Afterward, different amounts of CPC were added
and pressed using mechanical expellers (~750 psi), which into the premix (CPC: premix weight ratios 1:1, 1:2, 1:4,
extracted part of the canola meal oil as intact canola oil. 1:6, 1:8, 1:12, and 1:16), and the mixtures were vortexed
The residues from the mechanical expellers, known as the (using a vortex shaker at 2,500 rpm, Heidolph, Germany)
CPC, still contained some oil; therefore, its residual oil was for 60 s, followed by heating in a water bath (40 – 90°C, for
conventionally recovered using hexane (solvent: CPC ratio 10 – 120 min), while shaking. Finally, the mixtures were
of 0.8 L:1.2 kg) under controlled conditions. In this study, cooled to ambient temperature and centrifuged (10,000 g,
the CPC was collected and used as the substrate. 10 min). It is noteworthy that ME premix was the mixture
Solvents, including hexane, 1-propanol, and ethanol that typically contained surfactant: co-surfactant: water.
(96%), were purchased from Sigma-Aldrich Chemical Co For the Tweens/Span-based systems, these were
(United States). Tween 80 (BP338-500, Fisher Bioreagents, added to water (0 – 22% w/w) and thoroughly mixed.
United States) and Span 80 (1338-43-8, TCI America, United The co-surfactant (i.e., ethanol or 1-propanol) was then
States) were used as synthetic biodegradable surfactants. added if required, and mixing continued. Afterward,
Two types of fractionated soy lecithin, namely Epikuron different ratios of CPC were mixed with the Tween/Span
135F (a highly viscous liquid, acetone insoluble, containing dispersions (1:1, 1:2, 1:3, 1:4, 1:6, 1:8, 1:12, 1:16, and 1:32).
54.2% phosphatides, 35.7% phosphatidylcholine, and In some cases, the required ratio of co-surfactant was first
undetermined oil content) and Epikuron 170 (a semi-solid, mixed with CPC and mildly heated, then the mixture was
containing 97% phospholipids, 72% phosphatidylcholine, added to the Tween: water mixture, and the mixtures were
and <2% oil), were donated by Cargill (United States). vigorously mixed (using a vortex shaker at 2,500 rpm,
Heidolph, Germany) for 60 s, followed by heating in a
2.2. Composition of CPC water bath (40 – 90°C, for 10 – 120 min) while shaking.
The moisture content (105°C, 24 h), oil content (Soxhlet Finally, the mixtures were cooled to ambient temperature
method), and nitrogen content (automatic protein analyzer, and centrifuged (10,000 g, 10 min). In some cases, the pH
FOSS, Kjeltec™ 8400) of CPC and pellets (partially or of the mixtures was measured using a pH meter. For pH
completely de-oiled) were determined according to the adjustment in alkaline regions (pH = 10.0), NaOH (4N)
established analytical methods. 25 and HCl (4N) were used.
2.3. Size distribution of CPC 2.5. Oil extraction rate
Large CPC lumps (>10 cm) were manually crushed Upon centrifugation of CPC: premix mixtures, they were
(<2 cm) and then pulverized using a mortar and pestle. The visually separated into three or four distinct phases: Oil (top
powdered CPC was sieved using a nest of sieves, including layer), cream (thin layer beneath the oil phase), emulsion
mesh #5, 10, 18, 30, 40, and 500 (from top to bottom in or premix (middle layer), and pellet (bottom layer)
ascending order), with nominal openings of 4000, 2000, (Figure 1). To evaluate the oil extraction capability of the
1000, 595, 420, and 25 μm, respectively. Briefly, 400 g of surfactant-assisted solutions or ME premixes, the free oil
CPC was placed on top of sieve #5, and the nest of sieves phase was carefully aspirated using disposable pipettes and
vibrated for 20 min. The particles retained on each mesh weighed, or its volume was measured. The volume was then
were weighted and recorded as mass fractions. The mass converted to weight (or vice-versa), and the percentage of
mean diameter of the CPC particles was calculated by oil extraction or oil recovery was recorded. In addition, as
averaging the aperture size of two consecutive sieves and part of the extracted oil may have already been emulsified,
multiplying it by the mass fraction. the pellet phase was dried, and its oil content was extracted
using the conventional Soxhlet method. By subtracting
25
2.4. Formulation of MEs the oil content of the pellets from the initial oil content of
For the preparation of lecithin-based ME premixes, the CPC, the oil recovery rate was calculated. To account
lecithin was first dissolved in 1-propanol, used as a for variations in oil content and extraction efficiency, the

Volume 2 Issue 2 (2025) 3 doi: 10.36922/eer.6562