Unravelling the Mechanism of Stabilization and Microstructure of Oil-in-Water Emulsions by Native Cellulose Microfibrils in Primary Plant Cells Dispersions

Abstract

It is long known that oil-in-water emulsions can be stable against coalescence in homogenized plant cell wall dispersions due to the presence of surface active biopolymers. When plant cell wall material is homogenized to the extent of deagglomeration of the cellulose microfibrils (CMFs), a much more complex dispersed system is obtained. Here we show that in such complex systems both surface active soluble polymers and individual CMFs are at the origin of this stabilization against coalescence, as they form a shell around the oil droplets providing Pickering-like stabilization. Individual CMFs and bundles of them in the presence of soluble biopolymers form a hybrid network in the continuous phase linking the droplets, creating a viscoelastic network that prevents the droplets from coalescing. Depletion induced attraction caused by soluble biopolymers and dispersed CMFs induces the formation of oil droplet clusters at low CMF concentrations leading to a highly heterogeneous distribution of oil droplets. This effect diminishes at high CMF concentrations at which the strong viscoelastic network arrests the droplets. These findings are important steps towards controlling complex dispersed systems comprising CMF-polymers mixtures with a second liquid or solid dispersed phase.

New Insights into the Formulation and Polymerization of Pickering Emulsions Stabilized by Natural Organic Particles

“…After extraction from natural vegetal sources, it can be isolated under different insoluble forms and thereafter used without further modification to stabilize Pickering emulsions. Indeed, by physical destructuration it is possible to isolate microfibrils (CMF), themselves constituted of nanofibrils − (CNF), and by acid hydrolysis of the amorphous parts of these respective fibers one can obtain microcrystals − (MCCs) and nanocrystals ,− (CNCs), the latter being purely crystalline objects. It has been demonstrated that these objects are highly hydrophilic but present amphiphilic properties thanks to their surface chemistry. , As their surface presents a lot of hydroxyl functions, chemical modification is easy to perform.…”

Oleogel Films Through the Pickering Effect of Bacterial Cellulose Nanofibrils Featuring Interfacial Network Stabilization

“…There are two main hypotheses for the stabilizing mechanism of Pickering emulsions stabilized with BC/CCS: (1) the hybrid particles are adsorbed at the oil–water interface and resulted in a two or three-dimensional network between emulsion droplets, which inhibit its free movement and coalescence; (2) the deposited particles can form a solid interfacial film around the oil droplet to enhance the steric barrier between the droplets, which can further prevent coalescence and enhance the stability of the Pickering emulsions. Compared with other emulsion systems, the resultant emulsion stabilized with BCNFs and CCS exhibited long-term excellent storage stability. − …”

Biobased Cellulose Nanofibril–Oil Composite Films for Active Edible Barriers

“…Depletion effects of the nonadsorbed CNFs explain the stability of the emulsions against creaming. 15…”