Foaming properties of proteins

Table II. Factors affecting foaming properties of proteins.

R.D. Waniska and J.E. Ninsella, Foaming properties of proteins evaluation of a column aeration apparatus using ovalbumin, J. Food Sci. 44 (1979) 1398-1402. 

Limited alkaline hydrolysis is used to enhance solubility, emulsifying and foaming properties of proteins (2). 

Chen, S.A. (2003). Modification of foaming properties of proteins. United States Patent US651636B2. 

Alahverdjieva, V. S. Khristov, Khr. Exerowab, D. Miller R. Correlation between adsorption isotherms, thin Uquid films and foam properties of protein/surfactant mixtures Lysozyme/CIODMPO and lysozyme/SDS Colloids and Surfaces A Physico-chem. Eng. Aspects. 2008,323,132-138. 

The foaming properties of protein derivatives are also important features for their use in shampoos. They enable formulators to reduce the level of active surfactants in shampoos without reducing overall foaming power. This becomes of great importance in the formulation of low-active, frequent-use type shampoos where overall foaming effects can still be maintained at low-active levels, minimizing skin and eye irritation. 

Brierley, E.R., Wilde, P.J., Onishi, A., Hughes, P.J., Simpson, W.J., Clark, D.C. (1996). The influence of ethanol on the foaming properties of beer protein fractions a comparison of Rudin and microconductivity methods of foam assessment. Journal of the Science of Food and Agriculture, 70, 531-537. 

Mitchell, J.R. (1986). Foaming and emulsifying properties of proteins. In Hudson, B.J.F. (Ed.). Developments in Food Proteins 4, London Elsevier Applied Science, pp. 291-338. 

Aeration. This interphasic property of protein products, also called foaming or whipping, depends on the ability of the protein to form protective films around gas bubbles. Coalescence, and subsequent break-up of the membrane-like system around the bubbles by the proteins is thereby prevented (55-60). 

These data demonstrate that changes in foam properties of liquid cyclone processed cottonseed flour are inducible by treatment with succinic anhydride. Gel electrophoretic and solubility data show that there are alterations in the physical and chemical properties of proteins, and in certain cases these changes improve foam properties, that is, improve solubility and polypeptide dissociation of proteins at the interface of the foaming solution. Similar results have been reported for succinylated soybean and sunflower seed proteins (44. 46). 

The binding of fluorescent probes of different hydrophobicities can be used to compare the surface properties of proteins in relation to their physicochemical properties, such as foaming and emulsifying. CPA (cfr-parinaric acid) has been used to study eleven food-related proteins, and the results have been compared with theoretical models for predicting foam capacity (Arteaga and Nakai, 1993 also see... 

Advantages Surface hydrophobicity is often positively correlated with emulsifying and foaming properties of a protein. 

Table I shows that the foaming properties of whole casein improved by slight phosphorylation. The lowest phosphorylated form of casein (4 mol P/mol protein) showed higher foam hydration and stability than the native whole casein. However, the highly phosphorylated whole casein (11 mol P/mol protein) showed poor foaming properties. The foam hydration of as-casein deteriorated while that of K-casein improved by phosphorylation. This discrepancy seemed to be caused by a different initial hydrophobic/ hydrophilic balance of the proteins in their native states. However, foam stabilities of all casein fractions were reduced by phosphorylation, with K-casein being only slightly affected.

Figure 3. Solubility and foaming properties of cottonseed proteins at various pH...

Figure 7. Effect of pH and suspension medium on the foaming properties of peanut proteins. Suspension medium (0—0) Hs0, (O------O) 0.1M NaCl, (O O)...

Partial proteolysis has been used by several researchers to improve functional properties, i.e. foaming, solubility of proteins (7,8,9). The significant problems associated with enzyme hydrolysis of proteins are excessive hydrolysis occurring under batch conditions, the generation of bitter flavors during hydrolysis and the cost of enzymes. Extensive information on factors affecting proteolysis of proteins and the problem of bitterness has been reviewed by Fujimaki et al. (7) in conjunction with studies of the plastein reaction. 

Acetylated cottonseed protein demonstrated significantly higher water and oil holding capacities and improved foaming properties (38) compared to unmodified proteins (Table III). Thus, while acetylation does not significantly enhance functional properties of proteins, it improves thermal stability and since acetylated proteins are susceptible to enzyme hydrolysis in vivo it affords a useful reagent for protection of e-NH groups of lysine (11). 

Solubility is a critical functional characteristic because many functional properties depend on the capacity of proteins to go into solution initially, e.g. gelation, emulsification, foam formation. Data on solubility of a protein under a variety of environmental conditions (pH, ionic strength, temperature) are useful diagnostically in providing information on prior treatment of a protein (i.e. if denaturation has occurred) and as indices of the potential applications of the protein, e.g. a protein with poor solubility is of little use in foams). Determination of solubility is the first test in evaluation of the potential functional properties of proteins and retention of solubility is a useful criterion when selecting methods for isolating and refining protein preparations (1). Several researchers have reported on the solubility of extracted microbial proteins (69,82,83,84). In many instances yeast proteins demonstrate very inferior solubility properties below pH 7.5 because of denaturation. 

Hawks, S.E., Phillips, L.G., Rasmussen, R.R., Barbano, D.M., and KinseUa, J.E., Effects of processing treatment and cheesemaking parameters on foaming properties of whey protein isolates, J. Dairy Sci. 76, 2468, 1993. 

Superior foaming properties of milk have been obtained by addition of calcium complexing agents. Kelly and Burgess (1978) demonstrated that addition of sodium hexametaphosphate to milk protein concentrate solutions prepared by ultrafiltration improved foam volume and stability on whipping. The addition of EDTA to milk, which causes dissociation of the casein micelle, improved the foaming properties of milk (Ward et al., 1997). 

Firebaugh, J.D., and Daubert, C.R. (2005). Emulsifying and foaming properties of a derivatized whey protein ingredient. Int. J. Food Prop. 8,243-253. 

Kelly, P.M. (2006). Innovation in milk powder technology. Int. J. Dairy Technol. 59,70-75. Kelly, P.M., and Burgess, K.J. (1978). Foaming properties of milk protein concentrate... 

Kinsella, J.E. Properties of proteins possible relationships between structure and function in foams. Food Chem., 7, 273, 1980. 

FIGURE 11.5 Foaming properties of some proteins (solution of 0.25 mg per ml) in relation to the dynamic surface tension, y is surface tension d In A/dt is the surface expansion rate d is the approximate average bubble diameter. (After results by H. van Kalsbeek, A. Prins. In E. Dickinson, J. M. Rodriguez Patino, eds. Food Emulsions and Foams. Roy. Soc. Chem., Cambridge, 1999, pp. 91-103.)... 

Lim et al. (2008a,b) demonstrated that application of high pressnre (300 MPa, 15 min) conld enhance the foaming properties of WPG, which was added to low-fat ice cream to improve its body and texture. Due to the impact of high pressure on the fnnctional properties of whey proteins, the ice-cream mix containing the pressnre-treated whey protein exhibited increased overrun and foam stability and hardness than ice cream produced with untreated whey protein. 

The adsorption of proteins at interfaces is a key step in the stabilization of numerous food and non-food foams and emulsions. Our goal is to improve our understanding of the relationships between the sequence of proteins and their surface properties. A theoretical approach has been developed to model the structure and properties of protein adsorption layers using the analogy between proteins and multiblock copolymers. This model seems to be particularly well suited to /5-casein. However, the exponent relating surface pressure to surface concentration is indicative of a polymer structure intermediate between that of a two-dimensional excluded volume chain and a partially collapsed chain. For the protein structure, this would correspond to attractive interactions between some amino acids (hydrogen bonds, for instance). To test this possibility, guanidine hydrochloride was added to the buffer. A transition in the structure and properties of the layer is noticed for a 1.5 molar concentration of the denaturant. Beyond the transition, the properties of the layer are those of a two-dimensional excluded volume chain, a situation expected when there are no attractive interac-... 

Studies on the protein deamidation in food systems has recently been of great interest to the food industry. This is due to the fact that the deamidation reaction changes functional properties of protein such as solubility, emulsion property, and foaming ability... 

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