Cellulose nanofibers enable the thermoelastic structuring of agar-based gels mimicking beef intramuscular fat

In recent decades, the development of plant-based meat alternatives has been hindered by the lack of fat analogues that can replicate the key thermoelastic properties of animal fat during cooking. This study presents a novel strategy for structurally and thermally reinforcing agar-based emulsion gels by incorporating cellulose nanofibers (CNFs). Emulsion gels containing 0-1 wt% CNFs were compared with beef intramuscular (IM) fat. Increasing the CNF concentration significantly reduced the oil droplet size and produced a denser, entangled fibrillar network, in which the CNFs acted as nanoscale reinforcing scaffolds within the agar matrix. The gel containing 1 wt% CNF exhibited mechanical properties comparable to those of IM fat under ambient conditions, including similar hardness (848 vs. 858 g·force) and springiness (0.82 vs. 0.83). Temperature sweep rheology and meltability assessments consistently showed that CNF incorporation mitigated thermal softening and structural collapse, enabling enhanced modulus retention up to ∼100 °C and preserving over 80% of the original gel height during oven heating. Additionally, CNF incorporation enhanced water-holding capacity while reducing the fraction of freezable water, highlighting its potential for use as an effective reinforcing component to mitigate freeze-thaw-associated destabilization and suppress time-dependent water loss during ambient temperature storage. Collectively, these results demonstrate that CNF-agar reinforced emulsion gels can be engineered to partially reproduce critical thermo-mechanical characteristics of animal IM fat, highlighting their practical potential as structurally stable fat analogues for plant-based meat applications.