All-aqueous emulsions stabilized by sporopollenin exine capsules

D. Soto Aguilar (Contributor), E. Scholten (Contributor), V. Fogliano (Contributor), A. Madadlou*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


The efficacy of sporopollenin exine capsules (SpECs) for stabilization of all-aqueous emulsions was assessed. Cytoplasmic substances were removed from Lycopodium clavatum spores to obtain the SpECs. SpECs had a comparable morphology with the parent spores, and a size of ∼31 μm. The all-aqueous emulsions were prepared with polyethylene glycol (PEG) and dextran (Dex) at different PEG: Dex concentration ratios between 2:9 and 18:1. Confocal microscopy imaging showed that the emulsions were Dex-continuous at PEG: Dex concentration ratios of 2:9 and 4:8 and PEG-continuous at the ratios ≥6:7. When the SpECs were initially suspended within the PEG phase, the Dex-continuous emulsions could not be stabilized. The SpECs also failed to stabilize the emulsion with a ratio of 6:7, where the emulsions transitioned to PEG-continuous. However, the SpECs could stabilize a bottom emulsion phase, consisting of Dex-rich droplets within the PEG exterior phase, at concentration ratios ≥8:6. We hypothesized that a Pickering-type stabilization mechanism at the aqueous-aqueous interface of Dex droplets account for the emulsion stability, together with a possible formation of SpEC particle rafts. The emulsion stability at a concentration ratio of 8:6 was dependent on its pH; stable emulsions were formed at pH 7, but at pHs 2 and 4, the emulsions became unstable. These results were attributed to the high ζ-potential (−31 mV) of the SpECs at pH 7. These results show that repulsion between dispersed droplets was more important than the packing of the particles at the interface itself.
Original languageEnglish
Article number109447
Pages (from-to)1-9
JournalFood Hydrocolloids
Issue numberpart A
Publication statusPublished - Mar 2024


  • Lycopodium clavatum
  • Capillary force
  • Water-in-water emulsion


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