Improving stability and UV protection properties of phycocyanin nanoparticle-based Pickering emulgels via amorphous...

This study developed a novel phycocyanin nanoparticle (PCN) stabilized Pickering emulgel through the incorporation of amorphous cationic cassava starch (CCS), aiming to enhance stability and UV protection performance. The PCN/CCS complexes were fabricated by adjusting the PCN/CCS mass ratio (4:1-1:3), with optimal wettability (θ = 90.8°) achieved through precise surface properties modulation. Further analysis revealed that electrostatic and hydrophobic interactions dominated the PCN/CCS formation. Systematic investigation of oil phase content, particle concentration, and PCN/CCS ratio showed that the emulgel exhibited superior colloidal stability at an oil fraction of 70 %, an emulsifier concentration of 1 %, and a PCN/CCS ratio of 3:1. Notably, the CCS demonstrated bifunctional characteristics, serving as both co-stabilizer and gelling agent. Its long molecular chains construct a dense and cohesive gel network, conferring exceptional resistance to thermal (25-90 °C), pH (3-11), ionic (0-500 mM), centrifugation (4000 rpm, 10 min), and freeze-thaw stress. The emulgel exhibited markedly enhanced UV shielding, retaining 49.7 % of β-carotene and 23.8 % of astaxanthin after 72 h of exposure. These findings provide insights for designing innovative emulsification systems and the photoprotection of light-sensitive compounds for applications in cosmetics, food, and pharmaceuticals.