Oxidation Mechanism in Bigels and Emulgels-Challenges and Solutions

Area of Science:

• Food science and technology
• Colloid and surface chemistry
• Lipid chemistry

Background:

• Unsaturated fatty acids, particularly omega-3s, are prone to oxidation, posing formulation challenges.
• Bigels and emulgels are promising structured lipid systems for replacing unhealthy fats but face oxidative stability issues.
• Water presence exacerbates oxidation in food formulations.

Purpose of the Study:

• To review oxidation mechanisms in biphasic bigel and emulgel systems.
• To identify factors influencing oxidative stability in these systems.
• To outline strategies for enhancing oxidative stability in food applications.

Main Methods:

• Examination of free-radical-mediated autoxidation and metal-ion-catalyzed oxidation pathways.
• Analysis of the role of the oil-water interface as a reaction zone.
• Investigation of structural configuration effects (W/O, bicontinuous, O/W) on stability.
• Assessment of mass transfer mechanisms (diffusion, collision-exchange, micelle-assisted).

Main Results:

• Oxidation concentrates at the oil-water interface, influenced by pro-oxidants and lipid accessibility.
• Oxidative stability follows the order: W/O bigel > bicontinuous bigel > O/W bigel.
• Gel matrix viscosity offers protection by limiting radical mobility and oxygen diffusion.
• Thermal processing above 50 °C disrupts structures and accelerates degradation.

Conclusions:

• Oxidative stability in bigels and emulgels is governed by interfacial chemistry, structural configuration, and mass transfer.
• Protective strategies include interfacial engineering, natural antioxidants (phenolics, tocopherols), and synergistic combinations.
• A mechanistic framework is provided for developing oxidatively stable bigels and emulgels for food use.