Enhancing the stability and gel network of Pickering emulsions via pH and salt regulation: a study on CNF/EGCG complexes

This study developed high-performance emulsion gels stabilized by cellulose nanofiber/epigallocatechin gallate (CNF/EGCG) complexes and investigated the effects of pH and NaCl concentration on their properties. Emulsion gels were prepared via one-step high-speed shearing. Results showed that lowering pH or increasing NaCl concentration decreased electrostatic repulsion, leading to particle aggregation and reduced droplet sizes. Rheological analysis revealed that emulsion gels prepared at lower pH or with 900–1500 mM NaCl exhibited higher apparent viscosity and viscoelastic moduli. These structural enhancements resulted in improved centrifugal and freeze–thaw stability. Additionally, all gels demonstrated excellent thermal and storage stability over 30 days. Overall, the findings indicate that acidic conditions and salt addition effectively tune the interfacial and bulk properties of CNF/EGCG-stabilized emulsion gels by strengthening the gel network. This work provides insights into the design of cellulose/polyphenol-based emulsion systems for applications in food and related industries.