Emulsifying activity index

Functionality Analysis. Solubility was determined on 1% (w/v) dispersion of protein in 0.2 M phosphate buffers at a pH of 3.0 to 8.0. After stirring for 0.5 hr, the dispersion was filtered (0.45 /xm. Millipore), and the filtrate was analyzed for protein by the BCA method (21). Emulsifying activity index (EAI), expressed as interfacial area/unit weight protein (mVg) / was assessed by the turbidometric method of Pearce and Kinsella (22). 

Emulsifying activity index (EAI) is a measure of the ability of protein to emulsify oil, which depends on solubility, size, charge, and surface activity of the protein molecules. The effect of proteolysis with pronase E on EAI of the modified protein was relatively insignificant (Figure 6) However, deamidation appeared to enhance EAI, especially at pH values more basic than the isoelectric point (pH 4.7). 

Figure 6. Emulsifying activity index of soy proteins as a function of pH. Intact soy protein (O) soy protein proteolyzed with pronase E for 1 h (V) and 3 h ( ) deamidated soy protein ( ).

Effective Hamaker constant, 234 Emulsifying activity index, 186,188/ Emulsions, concentrated oil-in-water, effea of interdroplet forces on centrifugal stability, 229-245 Enhancers of taste. See Taste enhancers Enzymatic modification of soy proteins, 181-190... 

Cameron, D.R., Weber, M.E., Idziak, E.S, Neufeld, R.J., and Cooper, D.G. 1991. Determination of interfacial areas in emulsions using turbidimetric and droplet size data Correction of the formula for emulsifying activity index. J. Agric. Food Chem. 39 655-659. 

Emulsifying activity index The turbidity of a dilute emulsion is Emulsifying activity index... 

EAI. see Emulsifying activity index El. see Electron impact ionization Elasticity, gel rheology tests, see also Viscoelasticity... 

Emulsifying activity index (EAI), protein analysis, 297 (table)... 

The emulsifying activity index (EAI) curves for phosphorylated whole casein solution versus pH showed shift of their minima towards the acid... 

FIG. 3. Emulsifying activity index of native ( ) and phosphorylated whole caseins [4 (O) 7 ( ) and 11 (V) mol P/mol protein]. (Source From Haertle and Chobert (1999), by courtesy of Food Nutrition Press, Inc.)... 

Table IX. Emulsifying Activity Index Values Protein of Succinylated Yeast...

The emulsifying activity index and stability were also measured by Aluko and Monu (2003), who found high stability for the hydrolysate, but a small activity index. The hydrolyzed proteins are not as adequate for food emulsions as the protein concentrate. 

The importance of the hydrophobicity of the protein in determining the surface activity was demonstrated clearly by Kato and Nakai [2], As shown in Fig. la, the emulsifying activity index increases with the increase in the hydrophobicity index of various proteins. In a similar way, the increase in hydrophobicity index leads to a decrease in the interfacial tension (water-corn oil) (Fig. lb). Although these... 

Figure 1 Relationships of S with interfacial tension and emulsifying activity of proteins. I, bovine serum albumin 2, /3-lactoglobulin 3. trypsin 4, ovalbumin 5, conalbuntin 6, lysozyme 7, K-casein 8, 9, I0, II, and 12, denatured ovalbumin by heating at 85°C for l, 2, 3, 4, and 5 min respectively 13, 14, 15, 16. 17, and 18. denatured lysozyme by heating at 85"C for l, 2, 3, 4, 5, and 6 min respectively 19, 20, 21, 22, and 23, ovalbumin bound with 0.2, 0.3, 1.7, 5.7, and 7.9 mol of sodium dodecyl sulfate/mol of protein respectively 24, 25, 26, 27, and 28, ovalbumin bound with 0.3, 0.9, 3.1,4.8, and 8.2 mol of linoleate/mol of protein respectively. Interfacial tension measured at corn oil/0.20c protein interface with a Fisher Surface Tensiontat Model 21. Emulsifying activity index calculated from the absorbance at 500 nm of the supernatant after centrifuging blended mixtures of 2 ml of corn oil and 6 ml of 0.5% protein in 0.01 M phosphate buffer, pH 7.4 S initial slope of fluorescence intensity (FI) vs. percent protein plot. 10 /al of 3.6 mM m-parinaric acid solution was added to 2 ml of 0.002 to 0.1% protein in 0.01 M phosphate buffer, pH 7.4, containing 0.002% SDS. FI was measured at 420 nm by exciting at 325 nm. (From Ref. 2. Reprinted by permission.)...

We can quantify the emulsifying power of a molecule using the Emulsifying Activity Index (EAI). If I add a certain volume of oil V (the dispersed phase) to water (the continuous phase) with an emulsifier, the radius of the oil droplets formed R can be related to the increase in interfacial area by the simple expression... 

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