Catalyst-Free Fabrication of emulsion Gels from Cellulose-Based Pickering Emulsions via Synergistic Esterification and Hydrogen Bonding

Abstract

In this study, emulsion-templated oleogels (emulsion gels) were prepared through simply heating Pickering emulsions composed of carboxymethylated cellulose nanofibrils (CM-CN) and lemon essential oil (LEO). Based on Fourier-transform infrared spectroscopy (FTIR) and microstructural characterizations, a dual-crosslinking mechanism is proposed: thermal treatment is hypothesized to induce esterification between the carboxyl groups of CM-CN and the aldehyde groups of LEO, supplemented by enhanced multiple hydrogen-bonding interactions. The prepared emulsion gels exhibited a dense network microstructure with quantitatively improved physical properties. Under optimized conditions (80 °C, O/W ratio of 1:5), the emulsion gels achieved a maximum hardness of 107.66 g and a chewiness of 54.99 g. Dynamic rheological measurements confirmed a robust solid-like behavior with the storage modulus (G') consistently dominating the loss modulus (G''). Furthermore, lowfield NMR analysis indicated a significant reduction in transverse relaxation time (T2), reflecting restricted water mobility and excellent water-holding capacity, while the resulting aerogels demonstrated a compressive strength of up to 0.1121 MPa. This study presents a facile, catalyst-free heating strategy to fabricate emulsion gels using Pickering emulsion templates, offering a highly promising alternative to saturated and trans fats in the food industry.