Enhancing emulsifying properties of coconut endosperm pomace cellulose through ball milling, plasma, and...

This study adopts a green strategy to upcycle coconut endosperm pomace cellulose (CEPC), a coconut processing byproduct, into a food-grade Pickering stabilizer using physical modifications. This study aims to systematically compare the effects of ball milling (BM), dielectric barrier discharge plasma (DP), and ultrasonication (US) on the structural characteristics, interfacial behavior, and emulsifying performance of CEPC. After all three physical modifications, CEPC exhibited nanoscale particle size, reduced crystallinity, and enhanced surface wettability. Dilatational rheology demonstrated that US-modified CEPC (CEPC-US) formed an interfacial layer dominated by elasticity, with an elastic modulus of 21.09 mN/m, while quartz crystal microbalance with dissipation monitoring analysis confirmed its rapid adsorption kinetics and the formation of a thick interfacial layer (9.4 nm). Microrheology further correlates these interfacial properties with emulsion stabilization, demonstrating that CEPC-US forms aqueous cage structures around oil droplets with an elastic index of 0.01 nm² and a solid-liquid balance ratio of 0.28. These elastic aqueous cage networks stabilize emulsions with small droplets, high electrostatic repulsion, and 2.3 times improved centrifugal stability than untreated CEPC stabilized emulsion. Ultrasonication emerges as the most effective method, reducing CEPC crystallinity and enhancing its hydrophobic interactions. In contrast, BM generates nanosized particles with weaker interfacial adaptability, and DP fails to overcome structural rigidity despite carboxylation. These findings, for the first time, demonstrate that the ultrasonication method is ideal for enhancing the emulsifying properties of coconut endosperm pomace cellulose, offering new insights for the high-value utilization of fruit processing by-products.