Structural determinants of robust Pickering emulsions stabilized by microalgae-derived fibrous polysaccharide-protein complexes.

Microalgae byproducts contain a variety of high-value functional components. Previous studies have confirmed that extracts from Haematococcus pluvialis residues can be used to form stable Pickering emulsions. This study evaluated the efficacy and mechanism of action of fibrous polysaccharide-protein complexes extracted from Haematococcus pluvialis residues (FPHRs) as stabilizers for Pickering emulsions. Emulsions were prepared at concentrations ranging from 0.5 to 3 wt% and oil-to-water ratios between 0.2 and 0.7. The creaming index of the emulsions exhibited a positive correlation with the concentration of FPHRs, with emulsions at an oil-to-water ratio of 0.6 showing a minimum creaming index of 11 % after 14 days of storage, which showed the best emulsion stability. ζ-potential measurements demonstrated pH-independent stability, with values fluctuating between -20 and - 25 mV across a broad pH range. Thermal and ionic strength tests indicated no significant changes in particle size or appearance, suggesting robust emulsion stability. High-energy inputs reduced particle size but compromised emulsion stability; rheological analysis revealed that high-speed homogenization produced the most viscoelastic emulsions, underscoring the importance of fibrous structure for emulsion stability. These findings highlight the potential of FPHRs as a sustainable emulsifier, demonstrating that fibrous polysaccharide-protein complexes possess strong stability and can be effectively utilized in various food applications.