Emulsions protein stabilization

S. Mohan and G. Narsimham Coalescence of Protein-Stabilized Emulsions in a High-Pressure Homogenizer. J. Colloid Interface Sci. 192, 1 (1997). 

E. Tomherg Punctional Characterization of Protein Stabilized Emulsions Emulsifying Behavior of Proteins in a Valve Homogenizer. J. Sci. Pood Agric. 29, 867 (1978). 

T.D. Dimitrova and F. Leal-Calderon Forces Between Emulsion Droplets Stabilized with Tween 20 and Proteins. Langmuir 15, 8813 (1999). 

T.D. Dimitrova, F. Leal-Calderon, T.D. Gurkov, and B. Campbell Disjoining Pressure vs. Thickness Isotherms of Thin Emulsion Films Stabilized by Proteins. Langmuir 17, 8069 (2001). 

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

As reported in this chapter, the microscopic origin of both compressibility and elasticity of dense emulsions is rather well understood. Emulsions have elastic properties arising from either surface tension or surface elasticity and plasticity. Some protein-stabilized emulsions obey the same phenomenology as solid-stabilized emulsions they exhibit substantially higher osmotic resistances and higher shear moduli than surfactant-stabilized emulsions [38 0]. Moreover, they are strongly resistant to water evaporation. Proteins possess the ability to form... 

E. Dickinson and I. Chen Viscoelastic Properties of Protein-Stabilized Emulsions Effect of Protein-Surfactant Interactions. I. Agric. Food Chem. 46, 91 (1998). 

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. 

REHILL NARSIMHAN Protein-Stabilized Concentrated OIW Emulsions 231... 

Model for Centrifugal Stability of protein Stabilized Concentrated Emulsions... 

Hailing, P.J., Protein Stabilized Foams and Emulsions, CRC Critical Reviews in Food Science And Nutrition, 155 (1981). 

Centrifugal stability of protein-stabilized concentrated oil-in-water emulsions, 229-245 centrifugal acceleration, 237,238/ droplet size, 240,241/ film thickness vs. emulsion height, 237,239/240 ionic strength, 240,245/ model, 232-237 X parameters, 240,243/... 

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,... 

Damodaran, S. (2005). Protein stabilization of emulsions and foams. Journal of Food... 

McClements, D.J. (2004). Protein-stabilized emulsions. Current Opinion in Colloid and Interface Science, 9, 305-13. 

Figure 3.4 Effect of polysaccharide on protein-stabilized emulsions. The diameter ratio, j43nuxtlire / J43protem is plotted against the molar ratio R (moles polysaccharide / moles protein). Here J43nuxtlire is average droplet diameter in fresh emulsion prepared with protein + polysaccharide, and d43pTOtQm is average diameter in emulsion stabilized by protein alone. Key , , legumin + dextmn (48 kDa) or legumin + dextran (500 kDa), respectively (0.5 w/v % protein, 10 vol% oil, pH = 8.0, /= 0.1 M) (Dickinson and Semenova, 1992) O, , asi-casein + pectinate and p-casein + pectinate at pH = 7.0, / = 0.01 M (2.0 w/v % protein, 40 vol% oil), respectively , p-casein + pectinate at pH = 5.5, / = 0.01 M (2.0 w/v % protein, 40 vol% oil) (Semenova et al, 1999). Reproduced from Semenova (2007) with permission.

Dickinson, E., Pawlowsky, K. (1997) Effect of i-carrageenan on flocculation, creaming, and rheology of a protein-stabilized emulsion. Journal of Agricultural and Food Chemistry, 45, 3799-3806. 

For a colloidal system containing a mixture of different biopolymers, in particular a protein-stabilized emulsion containing a hydrocolloid thickening agent, it is evident that the presence of thermodynamically unfavourable interactions (A u > 0) between the biopolymers, which increases their chemical potentials (thermodynamic activity) in the bulk aqueous phase, has important consequences also for colloidal structure and stability (Antipova and Semenova, 1997 Antipova et al., 1997 Dickinson and Semenova, 1992 Dickinson et al., 1998 Pavlovskaya et al., 1993 Tsap-kina et al., 1992 Semenova et al., 1999a Makri et al., 2005 Vega et al., 2005 Semenova, 2007). 

Figure 7.9 Effect of pectin (DE = 76%) on (a) creaming of protein-stabilized emulsions (11 vol% oil, 0.6 wt% protein, 0.28 wt% pectin, I = 0.01 M) containing (A) asi-casein (pH = 7), (A) p-casein (pH = 7), and ( ) o i-casein (pH = 5.5) and (b) steady-state shear viscometry of casein-stabilized emulsions (40 vol% oil, 2 vt% protein). Apparent shear viscosity at 22 °C is plotted against stress pH = 7.0, / = 0.01 M, (A) -casein, (A) p-casein, ( ) ocsi -casein + 0.5 wt% pectin, ( ) p-casein + 0.5 wt% pectin, ( ) p-casein + 1.0 wt% pectin, (O) as[-casein + 1.0 wt% pectin pH = 5.5,1 = 0.01 M, (x) ocsi -casein, (O) as[-casein + 0.5 wt% pectin, ( ) oc -casein + 1.0 wt% pectin. Reproduced from Semenova (2007) with permission.

There seems to be a sort of analogy here with the arrested phase separation of a protein-stabilized depletion-flocculated emulsion containing a thermodynamically incompatible hydrocolloid like xanthan gum (Moschakis et al., 2005 Dickinson, 2006b). 

Table 7.2 Effect of the presence of an anionic polysaccharide on the measured zeta potential (Q of emulsion droplets stabilized by proteins under experimental conditions corresponding to protein-polysaccharide complexation. In all cases the complexes were formed in the bulk aqueous medium before emulsification.

In the study of Neirynck et al. (2007), the electrophoretic mobility data indicated that whey protein-stabilized emulsion droplets became gradually more negatively charged with pectin addition at pH = 5.5. This change was not only reflected in a smaller average droplet size, but also in a significant improvement in the creaming stability of the emulsions. 

---