AQUEOUS EXTRACTION OF OLEOSOMES FROM ISOLATED HULL-ENRICHED AND KERNEL-ENRICHED FRACTIONS OF CANOLA SEED

Oleosomes (oil bodies) are intracellular lipid storage organelles naturally stabilized by a phospholipid–protein membrane and represent promising bio-based alternatives to synthetic emulsifiers. While canola (Brassica napus L.) is a major oilseed crop, limited information is available on how seed anatomy influences oleosome recovery, composition, and structure. This research investigated the aqueous extraction and characterization of oleosomes from whole seed (WS) mechanically separated hull-enriched fractions (HEF) and kernel-enriched fractions (KEF) of InVigor L340PC canola. The work comprised two complementary studies. The first study evaluated fraction-specific oleosome recovery using aqueous extraction combined with sequential processing. In this context, sequential extraction refers to a multi-stage process in which the residual meal from each extraction step is re-extracted under the same conditions to maximize oleosome recovery. Due to KEF having a higher oil content, it produced the greatest cumulative emulsion yield across three extraction stages (48.7% ± 1.6% dry basis), exceeding WS by approximately 1.3-fold, whereas HEF yielded only 1.63% ± 0.10% emulsion yield (dry basis). The reported emulsion yield represents the mass of emulsion recovered relative to the initial dry weight of the sample. Sequential extraction significantly reduced sinapine levels, with reductions of 98% – 99% in WS and KEF meals and near-complete removal after three extraction stages (p < 0.05), which is important due to sinapine’s anti-nutritional effects in monogastric animals and off-flavour contributions in eggs (Gołębiewska et al., 2022, Annals of Animal Science, 22, 1163). Oil recovery correlated strongly with raw material oil content (R² = 0.98), indicating that fractions with higher oil content (KEF and WS) are extracted more efficiently under these aqueous conditions, whereas HEF retained approximately 88% of its initial oil content after extraction, reflecting limited extractability. The second study characterized the compositional and structural properties of the extracted oleosomes. Proton and carbon-13 nuclear magnetic resonance spectroscopy revealed fraction-dependent differences in triacylglycerol and fatty acid composition, with HEF-derived material exhibiting notably high levels of asclepic acid (C18:1 n-7; approximately 19%–25%). Microscopic emulsion analyses (scanning electron microscopy and confocal light scanning microscopy) showed spherical lipid-filled structures aggregated by interspersed proteins, ranging from sub-micron to several microns, with KEF forming more compact and uniform structures compared to the fibrous hull matrix. Particle size analysis further confirmed narrower distributions in KEF-derived emulsions, while sequential extraction reduced multimodality across WS, KEF and HEF. Evidence of reduced TAG content in HEF emulsions suggests partial enzymatic hydrolysis during processing. Overall, this research demonstrates that canola seed fractionation strongly influences oleosome yield, composition, and structural integrity. KEF represent the most efficient and consistent source of intact oleosomes, while HEF exhibit distinct lipid profiles but limited extractability under aqueous conditions. These findings advance the understanding of fraction-specific oleosome behavior and support the development of sustainable, clean-label oleosome-based ingredients for food and bio-based applications.

Name thesis:degree_name

Master of Science (M.Sc.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Food Science

Grantor

University of Saskatchewan

Year dc:date.issued

2026

Author dc:creator

• ., Yashmilan Kaur

Advisor dc:contributor.advisor

• Reaney, Martin

Committee members dc:contributor.committeemember

• Eskiw, Christopher
• Nickerson, Michael
• Tanaka, Takuji

• Canola (Brassica napus)
• oleosomes
• aqueous extraction
• seed fractionation
• kernel-enriched fraction (KEF)
• hull-enriched fraction (HEF)
• sequential extraction
• emulsion yield
• sinapine reduction
• triacylglycerols
• fatty acid composition
• nuclear magnetic resonance (NMR)
• confocal microscopy
• scanning electron microscopy (SEM)
• bio-based emulsifiers
• clean-label ingredients

Language dc:language.iso

en

Handle dc:identifier.uri

https://hdl.handle.net/10388/18238

OAI identifier oai:identifier

oai:harvest.usask.ca:10388/18238