Emulsification definition

An aqueous colloidal polymeric dispersion by definition is a two-phase system comprised of a disperse phase and a dispersion medium. The disperse phase consists of spherical polymer particles, usually with an average diameter of 200-300 nm. According to their method of preparation, aqueous colloidal polymer dispersions can be divided into two categories (true) latices and pseudolatices. True latices are prepared by controlled polymerization of emulsified monomer droplets in aqueous solutions, whereas pseudolatices are prepared starting from already polymerized macromolecules using different emulsification techniques. 

Control of the particle size while retaining precise control over the release rate is enabled by compartmentalization of the sol-gel solution into droplets of definite size. This can be achieved by emulsification of the sol-gel solution by mixing it with a solution composed of a surfactant and a non-polar solvent (Figure 2.13). When an active molecule is located in the aqueous droplet of a W/O emulsion, encapsulation occurs as the silicon precursors polymerize to build an oxide cage around the active species. By changing the solvent-surfactant combination, the particle size can be varied from 10 nm to 100 pm as the size of the particles is controlled by the size of the emulsion droplet, which acts as a nano-reactor for the sol-gel reaction (Figure 2.13). 

Edmondson et al (1971), who studied the enrichment of whole milk with iron, found that ferrous compounds normally caused a definite oxidized flavor when added before pasteurization. Aeration before addition of the iron reduced the off-flavor. The authors recommended the addition of ferric ammonium citrate followed by pasteurization at 81 °C. Kurtz et al. (1973) reported that iron salts can be added in amounts equivalent to 20 mg iron per liter of skim milk with no adverse flavor effects when iron-fortified dry milk is reconstituted to skim milk or used in the preparation of 2% milk. Hegenauer et al. (1979A) reported that emulsification of milk fat prior to fortification greatly reduced lipid peroxidation by all metal complexes. These researchers (Hegenauer et al. 1979B) concluded that chelated iron and copper should be added after homogenization but before pasteurization by a high-temperature-short-time process. 

Main drivers for membrane emulsification development include high product quality - especially when labile molecules are involved, precise definition of droplet-size distribution, low energy input, equipment modularity and easy scale-up, and low equipment footprint. 

Matz (208) also has reported on the improvements obtained with the use of lecithin in the production of cookies. Cookie dough is drier and more machinable with the use of lecithin. Lecithin improves the dispersion of fat so that it more readily mixes with sugar, flour, and other ingredients. Improved emulsification also reduces mixing times. Overdevelopment of the dough can result in lack of tenderness in the cookie. The release quality of lecithin improves the extrudabihty and release from the die, improving definition of impression. 

The factors which lead to the formation of emulsions are not definitely known. The most permanent emulsions are formed when an insoluble oil is shaken with a solution which contains a substance that interacts with one of the constituents of the oil to produce a colloid. This occurs when an oil containing free fatty acids is shaken with an aqueous solution of an alkali. A layer of soap is formed around the particles of the oil, and it is probable that a layer of oil may surround the colloidal partides of soap. When a solution of egg albumin is shaken with olive oil, a layer of the coagulated protein is formed around the drops of the oil and emulsification takes place. 

The emulsification tendency for a given combination of a diluent and the particular wastewater is generally quantified using the emulsification index [36]. Several definitions of this parameter have been published in the literature [35, 36]. The one published by Cooper and Goldenberg [37] is shown in Eq. (3). 

As expected from the definition of the HLB value, materials with high HLB values are O/W emulsifiers and materials with low HLB value are W/O emulsifiers. An HLB value of 3-6 is the recommended range for W/O emulsification 8-18 is recommended for O/W emulsification. Since the requirements for emulsification of a particular ingredient differ markedly, depending on whether the ingredient is the dispersed phase (O/W emulsion)or the continuous phase (W/O emulsion), each ingredient has a different HLB value, depending on which phase of the final emulsion it will become. Thus, paraffinic mineral oil has an HLB value of 11 for emulsification as the dispersed phase in an O/W emulsion and a value of 4 as the continuous phase in a W/O emulsion. 

First, 100 parts of m-dinitrobenzene is added to 1,000 parts of water at 90 C contained in a reducer fitted with a reflux condenser and a propeller-type stirrer. Upon emulsification, 245 parts of sodium sulfide (9HaO), dissolved in a minimum of water, is gradually run in. The dinitro compound is gradually reduced to m-nitroaniline, the end point being determined by the formation of a definite black streak when ferrous sulfate solution is added to filter paper spotted with some of the reducer liquor. 

Definition Complex mixts. of esters of phosphoric acid and hydroxycetyl alcohol Uses 0/w emulsifer, stabilizer, surfactant for pharmaceutical emulsions Manuf./Distrib. Chemos GmbH Nanjing Chemlin Somerset Cosmetic Co. 

Definition PEG ether of lanolin alcohol with avg. ethoxylation value of 50 Ionic Nature Nonionic Properties HLB 17.0 Uses Surfactant, emulsifer in cosmetics Manuf./Distrib. Somerset Cosmetic Co. Variati Laneth-60... 

---