Multicomponent oleogels of ethylcellulose-binary waxes: atomic force microscopy observation and synergistic effect...

Area of Science:

• Food Science and Technology
• Materials Science
• Rheology

Background:

• Interactions between ethylcellulose (EC) and waxes in multicomponent oleogel systems are not well understood.
• Oleogels are structured liquid oil systems with potential as solid fat substitutes.
• Rice bran oil (RBO) oleogels are being explored for their unique properties.

Purpose of the Study:

• To investigate the structural, functional, and physiochemical properties of RBO oleogels structured with varying ratios of EC and a binary wax blend (beeswax:carnauba wax).
• To determine the optimal ratio of EC and waxes for creating stable oleogels.
• To understand the role of EC and wax interactions in oleogel network formation.

Main Methods:

• Preparation of RBO oleogels using different ratios of EC and a 9:1 beeswax:carnauba wax blend at a constant total gelator concentration (4% w/w).
• Characterization using atomic force microscopy (AFM) for structural analysis.
• Evaluation of oil binding capacity (OBC), rheological properties (G', yield, flow points), gelation onset temperature, Fourier-transform infrared (FTIR) spectroscopy, and X-ray diffraction (XRD).

Main Results:

• All multicomponent systems formed self-sustaining oleogels at low gelator concentrations.
• AFM revealed co-existing structures of EC chains and wax crystals.
• Optimal OBC (99.94%) was achieved at 3.5% w/w wax, but resulted in a brittle gel; higher EC ratios improved yield and flow points but reduced G'.
• Higher EC ratios promoted early viscoelastic structuring, followed by wax crystallization.
• FTIR confirmed physical stabilization via hydrogen bonding and van der Waals forces; XRD indicated the presence of β' crystals with increased crystallinity and plasticity at higher wax ratios.

Conclusions:

• Ethylcellulose and binary wax mixtures can form stable oleogels with tunable structural and functional properties.
• The ratio of EC to waxes significantly impacts oleogel firmness, elasticity, and stability.
• These findings demonstrate the potential of EC-wax oleogels as effective solid fat substitutes.