Can we prevent lipid oxidation in emulsions by using fat-based Pickering particles?

Area of Science:

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

Background:

• Growing interest in food-compatible Pickering emulsions stabilized by biobased particles.
• Limited research on the chemical stability, specifically lipid oxidation, of particle-stabilized emulsions.
• Colloidal lipid particles (CLPs) identified as effective Pickering stabilizers.

Purpose of the Study:

• To investigate the oxidative stability of oil-in-water (O/W) emulsions stabilized by CLPs.
• To compare the oxidative stability of CLP-stabilized Pickering emulsions with conventional emulsions.

Main Methods:

• Preparation of sunflower oil-in-water (O/W) emulsions: Pickering emulsions with CLPs (tripalmitin or palm stearin) and conventional sodium caseinate-stabilized emulsions.
• Inclusion of high melting point (HMP) fat in some emulsions to study its effect on oxidation.
• Measurement of primary and secondary lipid oxidation products in the presence of iron.

Main Results:

• Emulsions with HMP fat in the core oxidized 2-3 times faster than conventional liquid oil and Pickering emulsions, likely due to HMP fat driving oxidizable lipids to the interface.
• CLP-stabilized Pickering emulsions exhibited similar oxidation rates to conventional sodium caseinate-stabilized emulsions containing only liquid oil.
• The potential of CLPs to prevent lipid oxidation appears limited, possibly because they do not form a homogeneous interfacial barrier against small pro-oxidant molecules.

Conclusions:

• The localization of solid fat within emulsion droplets significantly impacts lipid oxidation rates.
• CLP-stabilized Pickering emulsions offer limited advantages in preventing lipid oxidation compared to conventional emulsions.
• Further research is needed to enhance the chemical stability of particle-stabilized food emulsions.