Protein-stabilized oil-in-water

The objective of this paper is to illustrate the efficacy of inferring the interdroplet forces in a concentrated protein stabilized oil-in-water emulsion from the knowledge of the equilibrium profile of continuous phase liquid holdup (or, dispersed phase faction) when the emulsion is subjected to a centrifugal force field. This is accomplished by demonstrating the sensitivity of continuous phase liquid holdup profile for concentrated oil-in-water emulsions of different interdroplet forces. A Mef discussion of the structure of concentrated oil-in-water emulsion is presented in the next section. A model for centrifugal stability of concentrated emulsion is presented in the subsequent section. This is followed by the simulation of continuous phase liquid holdup profiles for concentrated oil-in-water emulsions for different centrifugal accelerations, protein concentrations, droplet sizes, pH, ionic strengths and the nature of protein-solvent interactions. 

Industrialization and need for increase in agricultural activity, 1-2 Inosine monophosphate, taste enhancer, 17,19 Interdroplet forces, effect on centrifugal stability for protein-stabilized oil-in-water emulsions,... 

Khalloufi, S., Corredig, M., Goff, H.D., Alexander, M. (2009). Flaxseed gums and their adsorption on whey protein-stabilized oil-in-water emulsions. Food Hydrocolloids, 23, 616-618. 

A certain body of recent research has focused on the microstructural stability of protein stabilized oil-in-water emulsions that are structurally similar to recently developed foodstuffs (e.g., dairy alternative or fresh cheese type products, etc.). - The image of such an emulsion has been visualized by the use of Confocal Laser Scanning Microscopy (CSLM). However, not much research has been done yet on the oxidative destabilization of these emulsion systems. A better understanding of the factors monitoring the oxidative deterioration of emulsions would offer antioxidant strategies to improve the organoleptic and nutritional value of the related products. 

Kiokias, S., Reiffers-Magnani, C., and Bot, A., Stability of whey protein stabilized oil in water emulsions during chilled storage and temperature cycling. J. Agric. Food. Chem., 52, 3823, 2004. 

A similar effect can be seen in protein-stabilized oil-in-water emulsions. For example, casein is known to form a thicker interfacial layer (lOnm) than whey proteins (l-2nm) (Dalgleish et al., 1995), which may explain, at least in part, why emulsions stabilized with casein tend to... 

Another characteristic property of many biopolymers (proteins, modified starch, chitosan, etc.) which is useful for the encapsulation of bioactive molecules is their ability to adsorb at the oil-water interface and to form adsorbed layers that are capable of stabilizing oil-in-water (OAV) emulsions against coalescence (see Table 2.2). It is worthwhile to note here that the formation of an emulsion is one of the key steps in the encapsulation of hydrophobic nutraceuticals by the most common technique used nowadays in the food industry (spray-drying). The adsorption of amphiphilic biopolymers at the oil-water interface involves the attachment of their hydrophobic groups to the surface of the oil phase (or even their slight penetration into it), whilst their hydrophilic parts protrude into the aqueous phase providing a bulky interfacial layer. 

Sun, C., Gunasekaran, S., Richards, M.P. (2007). Effect of xanthan gum on physicochemical properties of whey protein isolate stabilized oil-in-water emulsions. Food Hydrocolloids, 21, 555-564. 

Emulsion Capacity. Enzymatic digestion of proteins beyond 10 min, except the trypsin-treated sample for 30 min, destroyed emulsifying capacity of the flour (Figure 13). Apparently, hydrolysis substantially altered protein surface activity strengths and the ability of the protein to stabilize oil-in-water emulsions. This assumption agrees with earlier work showing decreased emulsion capacity of peanut flour fermented with fungi (27). 

Improved stability of lipophilic bioactives may be obtained by tailoring the interfacial membranes of oil droplets. Rosenberg and Lee (2004) coated a primary whey protein-based oil-in-water emulsion containing paprika oleoresin (as the model core) with calcium alginate to enhance the stability and control the core release. 

It is, therefore, clear that hydrophobic modifications of proteins can affect their ability both to form and to stabilize oil in water emulsions. Special care should be taken in using the proper combination of chain length and number of attached groups to the protein molecule in order to obtain good protein-based emulsifiers. 

After homogenization, the milk proteins readily adsorb to the bare surface of the fat droplets. The proteins are mostly adsorbed on the aqueous side of fat-matrix interface, with hydrophobic parts at the interface. Free casein, casein micelles and whey have different surface activities, so they adsorb differently onto the fat droplets for example, casein adsorbs more than whey. Proteins are very good at stabilizing oil-in-water emulsions against coalescence because they provide a strong, thick membrane around the fat droplet. Interactions between the proteins on the outside of the droplets make it harder for the droplets to come into close contact. This is known as steric stabilization. 

Gharsallaoui A, Saurel R, Chambin O et al. (2010) Utilisation of pectin coating to enhance spray-dry stability of pea protein-stabilised oil-in-water emulsions. Food Chemistry 122 447-454. 

Djordevic, D., Cercaci, L., Alamed, J., McClements, D.J., Decker, E.A. (2008). Chemical and physical stability of protein- and gum arabic- stabilized oil-in-water emulsions containing limonene. Journal of Eood Science, 73 C167-C172. 

Hu, M., McCIements, DJ. and Decker, E.A. Impact of chelators on the oxidative stability of whey protein isolate-stabilized oil-in-water emulsiuons containing (0-3 fatty acids. Food Chem. 88, 57-62 (2004a). 

The quality of the final encapsulated lipid powder depends on a number of factors including, the amount of Hpid encapsulated, the fraction of lipid exposed to the environment, the long-term chemical stability of the lipid, the flowability of the powder, the dispersibility of the powder, etc. These parameters can be controlled by selecting appropriate concentrations and types of components to make up the initial emulsion, as well as appropriate operating parameters for the spray dryer (e.g. flow rates, inlet, and outlet temperatures). Water soluble polymers (such as proteins and polysaccharides) are often used as emulsifiers to stabilize oil-in-water emulsions prior to spray drying, and after re-dispersion of the dried powder into liquid. Alternatively, water soluble polymers may make up part of the wall material that helps encapsulate and protect the lipid in the powder during storage. 

Khouryieh H, Puli G, Williams K, Aramouni F. Effects of xanthan-locust bean gum mixtures on the physicochemical properties and oxidative stability of whey protein stabilised oil-in-water emulsions. Food Chem. 167 340-348,2015. 

After heating at 40° C, liquid anhydrous milk fat (1 v) and the different protein solutions (10 v) were premixed using a polytron (PT 3000, Kinematica) and emulsified with a homogenizer (ALMO, Legrand, France) at about 40°C in order to obtain oil-in-water emulsions. After separation from the aqueous phase by centrifugation for 5 min at lOOOg, milk fat droplets stabilized by different proteins were washed twice with a phos-... 

Ice cream serves as a wonderful (and tasty) example of a complex, dynamically heterogeneous food system. A typical ice cream mix contains milk or cream (water, lactose, casein and whey proteins, lipids, vitamins, and minerals), sucrose, stabilizers and emulsifiers, and some type of flavor (e.g., vanilla). After the ingredients are combined, the mix is pasteurized and homogenized. Homogenization creates an oil-in-water emulsion, consisting of millions of tiny droplets of milk fat dispersed in the water phase, each surrounded by a layer of proteins and emulsifiers. The sucrose is dissolved in... 

A typical characteristic of many food products is that these are multi-phase products. The arrangement of the different phases leads to a microstructure that determines the properties of the product. Mayonnaise, for example, is an emulsion of about 80% oil in water, stabilized by egg yolk protein. The size of the oil droplets determines the rheology of the mayonnaise, and hence, the mouthfeel and the consumer liking. Ice cream is a product that consists of four phases. Figure 1 shows this structure schematically. Air bubbles are dispersed in a water matrix containing sugar molecules and ice crystals. The air bubbles are stabilized by partial coalesced fat droplets. The mouthfeel of ice cream is determined by a combination of the air bubble size, the fat droplet size and the ice crystal size. 

G. Narsimham Maximum Disjoining Pressure in Protein-Stabilized Concentrated Oil-in-Water Emulsions. Colloid Surfaces 62, 31 (1992). 

T.D. Dimitrova, F. Leal-Calderon, T.D. Gurkov, and B. Campbell Surface Forces in Model Oil-in-Water Emulsions Stabilized by Proteins. Adv. Colloid Interface Sci. 108-109, 73 (2004). 

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