Structure, Rheology and Stability of Walnut Oleogels Structured by Cellulose Nanofiber of Different Lengths

As acknowledged, the amphiphilic nature of nanocellulose could be widely used for structuring edible vegetable oils (both emulsion and oleogel). Here, the length of cellulose nanofiber (CNF), the most crucial parameters of CNF, was further investigated for its influences on the structure, stability and mechanical properties of CNFbased walnut oleogels via emulsions-templated approach. The results demonstrated that among the CNF length range from 0.2-2 mu m to 20-50 mu m, CNF factor with length of 2-5 mu m well stabilized walnut oil-water interface, promoted droplet dispersion, reduced droplet size, and therefore effectively improved the stability of emulsion. After the emulsion was dehydrated into oleogels, CNF molecules formed a better physical coverage of the liquid oil droplets, and thus improved the oil-binding capacity of oleogels (OBC of 89.0%). CNF with fiber length of 2-5 mu m stabilized the gelated structure, and remarkably enhanced the resistance of the oleogel to shear thinning. However, with the further increase of CNF length, the excessively enhanced hydrophilicity and entanglement probability of CNF weakened its ability to forming a stable gel structure, although the gel strength and structural rigidity of the oleogels ascended to some extent. Finally, this study fully exhibited the possibility of modulating intermolecular interactions during the oleogelation process by varying CNF fiber length, which benefited achieving high loadings of liquid vegetable oil in oleogels (OBC >= 85%) and simultaneously regulating the gel strength (G ' from 5.7 x 104 Pa to 2.4 x 105 Pa) and textural hardness (from 0.36 N to 0.67 N) over a wide range.