Champagne foams

Because proteins are involved in beer (Evans and Sheehan, 2002) and champagne foams (Senee et ah, 1999), and these are desirable properties, ultrafiltration is not a suitable treatment for these products. Adsorbents that indiscriminately remove protein are unsuitable for the same reason. 

The foam head created when beer is poured or dispensed, is an important aspect of consumer approval of a particular beer product. Compared with champagne foams, beer foams need to have different properties and be much more stable (beer foam needs to last for about five minutes). A cryogenic electron microscope image of beer foam is provided by Wilson [73]. Consumer preferences for beer foams vary, but can be characterized in terms of foam stability, quantity, lacing (adhesion to a glass surface), whiteness, creaminess (bubble texture), and concentration [852,853], As a result, much work has been done in order to be able to control these properties. 

Viaux, L., Morard, C., Robillard, B., and Duteurtre, B. (1994). The impact of base wine filtration on Champagne foam behavior. Am. J. Enol. Vitic., 45, 407-409. 

The foam head created when beer is poured or dispensed is an important aspect of consumer approval of a particular beer product. Compared with champagne foams, beer foams need to have different properties and be much more stable (beer foam needs to last for about 5 min). A cryogenic electron microscope... 

Foams consist of gases dispersed in a liquid. The nature of such foams varies depending on the situation. Some foams are transient with a short lifetime, for instance a Champagne foam, while other foams are more or less permanent, e.g. the foam formed in bread. 

Essentially, the stability of the foam depends on the stability of the individual film, with champagne foams being a classic example of an unstable foam (Figure 2.2(a)). In this case, the lifetime is controlled by the drainage (hydrodynamics), but also gas diffusion and Oswald ripening probably play a role in destabilizing the system. 

Figure 21.3. Typically, foams can be categorized as short-lived systems where film rupture is described as a spinodal decomposition (champagne foams), or long-lived systems in which energy barriers create an activation energy and film rupture is governed by a nucieation process (robust beer foams) (from ref. (7), reproduced with permission from lOP publishing limited...

It is also important to recognize that foams and emulsions are, in an absolute sense, thermodynamically unstable however, it is often possible to classify a particular system as relatively short-lived dynamically stabilized (ca. minutes) or one that can remain stable for very long periods (ca. days or years). A champagne foam is a classic example of the former, while robust beer foams and cosmetic creams fall into the latter category (see Figure 21.3). As already mentioned, this remarkable difference in a dispersion s lifetime is... 

Champagner, m. champagne, -weisse, /. a strongly foaming pale beer. 

Adsorbents that remove proteins or polyphenols are used to treat a number of beverages to delay the onset of haze formation. Protein adsorbents include bentonite and silica. Bentonite removes protein nonspecifically (see Fig. 2.19) and so is unsuitable for stabilizing beverages where foam is desirable (beer and champagne). Silica, on the other hand, has remarkable specificity for HA proteins while virtually sparing foam-active proteins in beer (Siebert and Lynn, 1997b) (see Fig. 2.20). Silica removes approximately 80% of the HA protein from unstabilized beer, while leaving foam-active protein nearly untouched at commercial treatment levels. 

Measured by nephelometric opto-electronical rapid methods. Brauwelt Int. 15, 228-234. Senee, J., Robillard, B., and Vignes Adler, M. (1999). Films and foams of Champagne wines. 

Actually, avalanches of popping bubbles were put in evidence during the coarsening of bidimensional and three-dimensional aqueous foams (Ritacco et ah, 2007 Vandewalle et ah, 2001). How does the bubble raft behave at the surface of a flute poured with champagne Does a bursting... 

Gendron R, Champagne MF, Delaviz Y, Polasky ME (2006) Foaming polystyrene with a mixture of C02 and ethanol. J Cell Plast 42 127-138... 

A transient foam that has no thin-film persistence and is therefore very unstable. Such foams exist only where new bubbles can be created faster than existing bubbles rupture. Examples air bubbles blown rapidly into pure water the foam created when a champagne bottle is opened. 

Cilindre, C., Castro, A.J., Clement, C., Jeandet, P., Marchal, R. (2007). Influence of Botrytis cinerea infection on Champagne wine proteins (characterized by two-dimensional electrophoresis/immunodetection) and wine foaming properties. Food Chem., 103, 139-149. 

Marchal, R., Tabary, I., Valade, M., Moncomble, D., Viaux, L., RobiUard, B., and Jeandet, R (2001). Effects of Botrytis cinerea infection on Champagne wine foaming properties. J. Sci. FoodAgric., 81, 1371-1378. 

Marchal, R., Chaboche, D., Doinllard, R., and Jeandet, P. (2002). Influence of lysozyme treatments on Champagne base wine foaming properties. J. Agric. Food Chem., 50, 1420-1428. 

Brissonnet, F. and Maujean, A. (1993) Characterization of foaming proteins in a champagne base wine, Am.]. Enol. Vitic., 44, 297-301. 

Blumwald, E., Aharon, G.S., and Lam, B.C.H. (1998). Early signal transduction pathways in plant-pathogen interactions, Trends Plant Sci., 3,342-346. Boiler, T. (1987). Hydrolytic enzymes in plant disease resistance, Plant-Microbe Interactions Molecular and Genetic Perspectives, 2,385 113. Brissonnet, F. and Maujean, A. (1993). Characterization of foaming proteins in a champagne base wine, Am. J. Enol. Vide., 44, 297-301. 

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