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Journal article
Trapped potential: Multi-scale analysis of structure-property relationships in oleogel-in-hydrogel bigels
Food hydrocolloids, Vol.182, 113126
2027
Abstract
Oleogel-in-hydrogel emulsions (referred to as ‘bigels’) are promising functional materials for structured foods, cosmetics and pharmaceutical formulations and offer tuneable properties for the control of sensory attributes and the encapsulation of both lipophilic and hydrophilic ingredients. In this study, we formulated canola oil/palmitic acid oleogel-in-agarose bigels and systematically investigated how the microstructure, crystallinity and mechanical properties are affected by composition and storage conditions. Diffusing wave spectroscopy revealed coalescence and phase separation above gelation temperatures, while cooling produced homogenous bigels. Confocal laser scanning microscopy and time-domain nuclear magnetic resonance spectroscopy revealed that as the oleogel fraction increased, the size of the dispersed phase droplets decreased, along with their crystallinity, as determined by differential scanning calorimetry. Synchrotron small- and wide-angle X-ray scattering revealed that regardless of the oleogel fraction, all bigels exhibited the same oleogel crystal structure and polymorphic form, with α polymorphs dominating, and remaining consistent upon temperature cycling and storage. Mechanical testing revealed that higher oleogel fractions provided more pliant bigels with lower compressive Young's moduli (Ec) but higher tensile moduli, indicating an anisotropic mechanical response linked to droplet size and interfacial area. Upon open-air storage, water evaporation from the agarose phase led to stiffer bigels, particularly with lower oleogel fractions. Storage in sealed containers at 23 or 4 °C maintained mechanical properties, while freeze-thaw cycles disrupted the agarose network and significantly decreased Ec values. The tuneable mechanical properties, stability and desirable polymorphic form of the bigels establish clear structure–property–storage relationships, making them promising candidates for use in structured foods, as potential fat substitutes.
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•Novel oleogel-in-hydrogel ‘bigels’ were formulated from palmitic acid and agarose.•Oleogel droplet size decreased with decreasing agarose volume fraction.•Oleogels adopted a lamellar structure with α and β′ polymorphs.•Ambient, open-air storage caused evaporation and stiffening of the agarose network.•Young's modulus increased with increasing agarose volume fraction.
Details
- Title
- Trapped potential: Multi-scale analysis of structure-property relationships in oleogel-in-hydrogel bigels
- Authors/Creators
- Ashlyn Austin - University of South AustraliaMarta Krasowska - University of South AustraliaAlaa Y. Bazeed - The University of AdelaideJames K. Ferri - Virginia Commonwealth UniversityKimberly Penzer - Virginia Commonwealth UniversityTodd A. Gillam - Murdoch University, School of Mathematics, Statistics, Chemistry and PhysicsAdrian D. Manning - Supreme Council Of HealthAnton Blencowe - University of South Australia
- Publication Details
- Food hydrocolloids, Vol.182, 113126
- Publisher
- Elsevier Ltd.
- Identifiers
- 991005909778407891
- Copyright
- © 2026 The Authors.
- Murdoch Affiliation
- School of Mathematics, Statistics, Chemistry and Physics
- Language
- English
- Resource Type
- Journal article
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