Composition and properties of the surface of oil bodies recovered from Echium plantagineum

Neutral-lipids within oilseeds are most commonly stored in oil bodies, small spherical organelles with oleosin proteins inserted through a phospholipid monolayer. Oil bodies extracted from Echium plantagineum are highly enriched in polyunsaturated fatty acids and are stable to coalescence and oxidation. This stability has been attributed to the strong association between the phospholipid monolayer and oleosin proteins. To better understand this association the phospholipid fatty acyl groups of E. Plantagineum oil bodies were determined for the first time; a large proportion (≈70%) of saturated fatty acids were present, and this may aid in oleosin anchorage and thus contributes to oil body stability. The effect of oil body washing on surface charge was also observed (using turbidity, zeta and streaming potentials), and dependent on the washing protocol, E. Plantagineum oil bodies had an isoelectric point of pH 4–5. This is significantly different to pI values for oil bodies from a range of other seeds reported in the literature using isoelectric focusing; a possible explanation for this discrepancy is discussed.