Controlled production of eco-friendly emulsions using direct and premix membrane emulsification (original) (raw)
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Food emulsions using membrane emulsification: conditions for producing small droplets
Journal of Food Engineering, 1999
Ceramic membranes were used to produce oil-in-water (O/W) emulsions consisting of vegetable oil as the dispersed phase and skim milk as the dispersion medium. The purpose of the work was to ®nd operating conditions suitable for producing small emulsion droplets, a small size being important for emulsion stability. The main parameters investigated were the eect of wall shear stress, emulsi®er concentration and membrane pore size. Formation of small droplets was favoured at higher emulsi®er concentrations and for a high wall shear stress using a membrane with a small nominal pore size. Submicron particles were produced at an 8% emulsi®er concentration for a wall shear stress of 135 Pa using a 0.1 lm pore size membrane. Under these conditions the¯ux was >100 kg m À2 h À1 . A high¯ux is important for industrial-scale production of food emulsions using membrane emulsi®cation. Ó
JOURNAL OF CHEMICAL ENGINEERING OF JAPAN
A novel method of emulsion preparation by intramembrane premix membrane emulsi cation without preliminary emulsi cation was developed for the preparation of monodispersed oil-in-water (O/W) and water-in-oil-in-water (W/O/W) emulsions with small droplet size and high disperse phase content at high productivity. The dispersed phase and the continuous phases were simultaneously permeated through Shirasu Porous Glass (SPG) membranes with mean pore sizes of 5, 10, and 20 µm at a membrane permeation rate over 50 m 3 /m 2 h. Monodispersed emulsions with disperse phase content of 25 to 95% by volume, mean droplet size to the mean pore size ratio of 1.2 to 0.26, and with droplet size distribution (span) of 0.4 to 0.6 were prepared. The emulsion droplet size decreased with membrane permeation rate, continuous phase viscosity and the number of membrane permeation cycles. A composite W/O/W emulsion with an average droplet size of 10.4 µm, a span of 0.5 and of disperse phase content of 50% by volume was also prepared in a sequence of consecutive steps without integrating the preliminary emulsi cation step by high-shear homogenization.
Production of more sustainable emulsions formulated with eco-friendly materials
Journal of Cleaner Production, 2019
Sustainable development involves the search for new products with a low environmental impact. Hence, the aim of this work is to obtain stable and concentrated aqueous emulsions containing bitter fennel oil and a biomass-derived emulsifier by studying different processing variables and techniques. Firstly, the effects of the application of a premix step previous to homogenization and of the geometry of the highenergy rotor-stator device used (Silverson L5M or Ultraturrax T50) on the droplet size distribution (DSD) and physical stability (PS) of emulsions were investigated. The use of a premix worsens both the physical stability and the average droplet diameters of the emulsions, the most stable emulsion being that obtained with the Silverson L5M alone. Secondly, the stability of this emulsion was improved. To achieve this goal, this coarse emulsion was microfluidized at different pressures (from 5000 to 25000 psi), reaching submicron sizes and monomodal distributions, except for that subjected to 25000 psi which resulted in clear overprocessing. Creaming and oiling off were the main destabilization processes. The emulsion exhibiting the lowest droplet sizes and the best physical stability was prepared at 20000 psi. This work contributes to the development of sustainable agrochemical prototypes.
Manufacture of controlled emulsions and particulates using membrane emulsification
2008
Crossflow and rotating membrane emulsification techniques were used for making oil-in-water (O/W) emulsions. The emulsions produced from a variety of oils and monomers (viscosity 7-528 mPas) exhibited narrow size distributions over a wide droplet size range, with the average droplet size ranging from less than 1 µm up to 500 µm. The monomer emulsions were further encapsulated to produce microcapsules through subsequent polymerisation reactions. The monodispersity feature of the primary emulsions was retained after the encapsulation. In comparison with other homogenisation methods, our experimental results demonstrated that the membrane emulsification technique is not only superior in emulsion droplet size controls, but also advantageous in energy efficiency and industrial-scale productions.
Preparation of water-in-oil and ethanol-in-oil emulsions by membrane emulsification
Fuel, 2010
In this work, water-in-oil emulsions (W/O) and ethanol-in-oil emulsions (E/O) emulsions were prepared successfully by membrane emulsification. The emulsifiers selected were PGPR and MO-750 for the W/O and E/O emulsions, respectively. For W/O emulsions prepared with an oil pre-filled membrane, the dispersed flux was lower and the droplet size sharper than that obtained with a water pre-filled membrane. On the contrary, for E/O emulsions prepared with the membrane pre-filled with oil, the dispersed phase (ethanol) rapidly pushed out the oil from the membrane pores. Therefore, the pre-treatment of the membrane had almost no effect on the dispersed phase flux and on the droplet size. The droplet size distribution of the E/O emulsion was close to that obtained with a classical homogenizer. The dispersed phase fluxes were high and no fouling was observed for our experimental conditions (1.6 l emulsion, 10 wt% ethanol). These results confirm that membrane emulsification could be an interesting alternative for the preparation of E/O emulsions for the purpose of biodiesel fuels, considering the scale-up ability of membranes and their potentiality for industrial processes.
Journal of Membrane Science, 2004
Multiple W/O/W emulsions have been prepared by multi-stage (repeated) premix membrane emulsification using Shirasu-porous-glass (SPG) membrane with a mean pore size of 10.7 µm. A coarse emulsion containing droplets with a mean particle size of about 100 µm was homogenized 5-6 times through the same membrane at a constant pressure difference of 20-300 kPa to achieve additional droplet homogenization and size reduction. The optimum conditions with regard to particle size uniformity were 3 homogenization cycles at a pressure difference of 100 kPa, under which the mean size of outer W/O particles was 9 µm and the span of particle size distribution was as low as 0.28. The optimum pressure difference in a single-stage process was higher, but the-2particle size distribution of prepared emulsions was broader than in a multi-stage process at smaller pressures. The transmembrane flux was in the range of 1.8-37 m 3 /(m 2 h) and increased with increasing pressure difference and decreasing the content of W/O particles. The mean size of W/O particles in each cycle was remarkably constant over a wide range of their concentration of 1-60 vol. %.
2017
This paper analyses the impact of two types of emulsifiers originating from milk: milk protein concentrate (MPC) and whey protein concentrate (WPC), on droplet size distribution using an asymmetric membrane process. The results indicated that the size, span and uniformity of oil droplets in emulsions depend on the velocity of shear stress on the internal surface of a membrane channel and on the physical and chemical parameters of the medium used as an emulsifier. The use of WPC produced an emulsion with optimum (the lowest) parameters of oil droplet size distribution. Switching from WPC to MPC resulted in an increase in the average characteristic diameter of the emulsion droplets and simultaneously caused widening of the distribution and a reduction in the uniformity index. STUDIA NAD ROZKŁADEM WIELKOŚCI KULECZEK TŁUSZCZOWYCH EMULSJI TYPU O/W OTRZYMANYCH Z WYKORZYSTANIEM MEMBRAN ASYMETRYCZNYCH Fabian Dajnowiec, Paweł Banaszczyk, Aleksander Kubiak, Malwina Biegaj, Lidia Zander Katedr...
Journal of Membrane Science, 2014
Membrane emulsification is a promising technology for the production of micro-nano particles, which is able to compete with the conventional mechanical emulsification processes. The production of emulsions with narrow droplet size distribution at dispersed phase fluxes (productivity) sufficiently high to make the process suitable for industrial application is still a considerable challenge. The interfacial tension between the dispersed phase and the membrane pore wall is a crucial parameter to maintain droplets shape while enhancing productivity. In the present paper, a membrane thickness with asymmetric properties in terms of wettability between external and internal sides has been tested in the preparation of W/O emulsions. The membrane surface wettability modification was obtained by adsorption of hydrophobic macromolecules on the lumen side of hydrophilic membrane. Lipase was used as a model macromolecule. W/O emulsion droplets with smaller droplets size have been produced with lipaseloaded membrane compared with the unmodified hydrophilic membrane. High dispersed phase flux of 30 L h À 1 m À 2 was also obtained with a significant increase of process productivity compared to the use of hydrophobic membranes. These results show that membrane-protein interaction can be used to functionalize opportunely the membrane for membrane emulsification application reducing emulsification time and increasing dispersed phase flux without modifying the control on droplets properties in terms of size and size distribution.