Soybean oleosomes studied by small angle neutron scattering (SANS)

作者：Zielbauer Birgitta I; Jackson Andrew J; Maurer Sania; Waschatko Gustav; Ghebremedhin Marta; Rogers Sarah E; Heenan Richard K; Porcar Lionel; Vilgis Thomas A

来源：Journal of Colloid and Interface Science, 2018, 529: 197-204.

DOI：10.1016/j.jcis.2018.05.080

• Oil bodies
• Oleosomes
• Oleosin
• Structure
• Shell thickness
• Size
• Core-shell model
• Contrast variation
• Small angle neutron scattering (SANS)
• Temperature

Hypothesis: Oleosomes are stabilized by a complex outer phospholipid-protein-layer. To improve understanding of its structure and stabilization mechanism, this shell has to be studied in extracellular native conditions. This should be possible by SANS using contrast variation. Oleosomes are expected to be highly temperature stable, with molecular changes occurring first in the protein shell. Direct measurements of changes in the shell structure are also important for processing methods, e.g. encapsulation.
Experiments: Extracted soybean oleosomes were studied directly and after encapsulation with pectin by SANS using contrast variation. In order to determine structure and size, a shell model of oleosomes was developed. The method was tested against a simple phospholipid-stabilized emulsion. The oleosomes' temperature stability was investigated by performing SANS at elevated temperatures.
Findings: Size (R-g=1380 angstrom) and shell thickness of native and encapsulated oleosomes have been determined. This is the first report measuring the shell thickness of oleosomes directly. For native oleosomes, a shell of 9 nm thickness surrounds the oil core, corresponding to a layer of phospholipids and proteins. Up to 90 degrees C, no structural change was observed, confirming the oleosomes' high temperature stability. Successful coavervation of oleosomes was shown by an increase in shell thickness of 10 nm after electrostatic deposition of pectin.

• 出版日期2018-11-1