Influence of a Non-Ionic Surfactant in the Microstructure and Rheology of a Pickering Emulsion Stabilized by Cellulose Nanofibrils

Abstract

Emulsion stabilization is a broad and relevant field with applications in oil, polymer and food industries. In recent years, the use of solid particles to stabilize emulsions or Pickering emulsions have been studied for their kinetic and physical properties. Nanomaterials derived from natural sources are an interesting alternative for this application. Cellulose nanofibrils (CNFs) have been widely explored as a Pickering emulsifier with potential food applications, however, in some cases the presence of surfactants is unavoidable, and the literature is devoid of an evaluation of the effect of a non-ionic food-grade surfactant, such as polysorbate 80, in the stabilization of a vegetable oil by CNFs. To better assess the possible interactions between CNFs and this surfactant emulsions containing coconut oil, an emerging and broadly used oil, were processed with and without polysorbate 80 and evaluated in their qualitative stability, morphological and physical properties. Fluorescence microscopy, dynamic light scattering and rheology were used for this assessment. Results indicate in absence of the surfactant, emulsion stability increased at higher CNFs content, creaming was observed at 0.15 and 0.3 wt.% of CNFs, while it was not evidenced when 0.7 wt.% was used. After the addition of surfactant, the droplets are covered by the surfactant, resulting in particles with a smaller diameter, entrapped in the cellulosic structure. Rheology indicates a lower network stiffness after adding polysorbate 80.

Physicochemical studies of novel sugar fatty acid esters based on (R)-3-hydroxylated acids derived from bacterial polyhydroxyalkanoates and their potential environmental impact

“…Nanomaterials derived from natural sources are an interesting alternative or supplementary for this application. ( Velásquez-Cock et al, 2021 ). In order to compare our surfactants for their feasibility in applications other than described below (drug delivery purposes), studies should be conducted in greater concentrations and with other additives.…”

Nanocelluloses review: Preparation, biological properties, safety, and applications in the food field

“…Modified NCs have been demonstrated faster adsorption, higher surface pressure, and coverage ratio (Saffarionpour, 2020; Velásquez‐Cock, et al., 2021). Thus, researchers further explored green and safe modified NCs for Pickering emulsions.…”

Nanocellulose from Cocoa Shell in Pickering Emulsions of Cocoa Butter in Water: Effect of Isolation and Concentration on Its Stability and Rheological Properties

“…Physicochemical and sensory attributes of emulsion-based food products are strongly influenced by droplet properties, such as droplet morphology, interactions, and rheological behavior [17]. There is a great deal of research attempting to link these properties in PEs [19][20][21][22]. Microscopic and rheological measurements can also be used to monitor changes in the structural organization and interactions of the droplets in emulsions.…”

“…While previous research on nanocellulose in PEs has been developed for dispersed phases that remain liquid or partially solidify, such as n-hexadecane [28], coconut oil [22], and olive oil [29], among others, they have focused on the morphology of the nanocellulose incorporated and used wood as the main cellulosic source, neglecting the influence of the isolation procedure for cellulose or alternative sources of cellulose, for instance, cocoa shells. This research is more relevant considering in the literature the use of cellulose nanofibrils to decrease oil or fat content in edible formulations, which helps to reduce the caloric value of food products while functioning as a dietary fiber, suggesting its possible use as a functional food ingredient with added health benefits [30][31][32].…”