Influence of surfactant and processing conditions in the stability of oil-in-water nanoemulsions

Abstract

a b s t r a c tThis work evaluates the influence of the type of surfactant (Tween 20, SDS and DTAB) and processing conditions on the stability of oil-in-water nanoemulsions, measured in terms of hydrodynamic diameter (H d ), polydispersity index (PdI) and zeta potential (Zp). Nanoemulsions were prepared using high-pressure homogenization based on a 2 4 level factorial design. Results show that processing parameters such as homogenization pressure, surfactant concentrations and oil:water ratio significantly affected the values of H d and PdI of nanoemulsions. The value of H d of anionic nanoemulsions decreased (from 177 to 128 nm) with the increase of the homogenization pressure. The increase in the surfactant concentration and the decrease of the oil:water ratio lead to a decrease of H d for the cationic nanoemulsions (from 198 to 135 nm). The increase of the oil:water ratio lead to a decrease of H d for the non-ionic nanoemulsions (from 341 to 171 nm); this is contrary to the usual assumption that higher content in oil results in higher values of H d . Those nanoemulsions showed a good kinetic stability (evaluated after centrifugation, heating-cooling cycles and thermal stress) upon measuring the H d during 28 and 35 days of storage, without visual evidence of creaming and phase separation. After one year of storage the nanoemulsions produced with the anionic surfactant remained kinetically stable, without visual evidence of creaming and/or phase separation.

Protective effect of sucupira oil nanoemulsion against oxidative stress in UVA-irradiated HaCaT cells

“…The choice of low molecular weight surfactants also contributed to the small‐sized droplets. This occurs due to the greater ease and speed of droplet adsorption during homogenization, and greater reduction of interfacial tension . Moreover, the combination of surfactants causes a greater decrease in the interfacial tension between water and oil, thus causing an efficient reduction in droplet size and in the tendency of the droplets for coalescence, consequently improving the stability of NEs when compared to NEs which use only one surfactant (Figures and ).…”

“…High-energy emulsifier-high-pressure homogenization technique was chosen for the preparation of NE for its better scalability to an industrial production, ease of operation and good reproducibility when compared to low energy emulsification method. [16,29] In addition, previous studies have demonstrated that NEs produced by methods involving high emulsification energy tend to be more stable than those produced by low-energy emulsification methods. This is due to the fact that smaller droplets are formed and are capable of avoiding destabilization phenomena, such as Ostwald ripening.…”

“…TNF-a, IL-1 and IL-6 play pathological roles in the development of skin inflammation and skin ageing induced by UV radiation. [29] IL-6 contributes directly to photoageing process through stimulation of metalloproteinase secretion by fibroblasts and collagenase activity, culminating in extracellular matrix proteins degradation in dermis. [60,61] On the other hand, IL-8 acts as a chemotactic factor that modules positively the inflammatory response mediated by UV radiation in skin.…”

Preparation of beta-carotene nanoemulsion and evaluation of stability at a long storage period

“…According to McClements (2015), agitation with a high speed facilitates the oil solubilization during the emulsification process, which explains the smaller diameter obtained for the nanoemulsion developed at 10,000 rpm. Regarding the concentration of the surfactant, this variable affects the size of globules and consequently the emulsion stability (Silva et al, 2015;Bernardi et al, 2011). High surfactant concentrations cause an increased interfacial area while reducing the interfacial tension, resulting in smaller droplet size (Pengon et al, 2018).…”

“…The physicochemical properties and stability of nanoemulsions are influenced by the process conditions (McClements, 2011;Silva et al, 2015). On a stable system, the globules dispersed in nanoemulsions maintain their initial characteristics and remain uniformly distributed by a continuous phase (Chung & McClements, 2018).…”