Foaming activity

The foamability of the xylans tested [128] was low in comparison to a commercial whipping protein DIOO. Only the highly viscous beech wood xylan and the rye bran AX-protein complex exhibited remarkable foaming activity, which was similar to that of gum arable. As the MGX polymers contain considerable amounts of uronic acid side chains, this may play a role in their foaming activity together with the presence of low amounts of Ugnin. 

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. 

FIGURE 2.19 The effects on foam active ( ) and HA ( ) protein of treating unstabilized beer with bentonite. Reprinted with permission from Siebert and Lynn (1997b). Copyright 1997 American Society of Brewing Chemists. 

Protein molecule with no polyphenol binding sites (e.g. foam-active protein)... 

Recently, proteolytic enzymes that cleave peptide bonds only adjacent to proline were introduced (Lopez and Edens, 2005). Since proline is involved in the polyphenol-binding sites and there is little proline in the foam-active proteins, these enzymes are specific for haze proteins and do little damage to foam proteins. 

Fatty Acid—Sarcosine Condensates. These surfactants are prepared by the reaction of fatty acid chlorides with methyl glycine sodium lauroyl sarcosinate [137-16-6] is an example of this group. They are most effective at pH 5.5—6.0 for foaming activity in soft to moderately hard water. The action of these deteigents is gready reduced under severe hard water conditions. The sarcosinates exhibit compatibility with cationic surfactants and have been suggested for use in formulation of conditioning shampoos (7). 

Brissonet, R, Maujean, A. (1991). Identification of some foam-active compounds in Champagne base wines. Am. J. Enol. Vitic., 42, 97-102. 

Within the extracts (thermal or enzymatic), besides polysaccharides, mannoproteins were proven to be the main components, the molecular characterization of which has been carried out using SEC and SDS-PAGE (Martfnez-Rodrfguez et al. 2007 Nunez et al. 2006). Results showed in both cell wall extracts a protein band corresponding to a relative molecular mass of 30kDa (Eig. 5.9). Moreover, three bands, which were absent from the extract obtained enzymatically, with relative molecular masses between lOkDa and 21.5 kDa were observed in the thermal extract. Only glycoproteins with Mr between 10 kDa and 21.5 kDa, were proven to be foam-active though the protein at 30 kDa (also present in the enzymatic extract) was found to be inactive. 

Disposal. An estimated 2.3 billion barrels of crude oil were produced in 1997 (API 1998a). From this crude oil, TPH waste may be generated in a number of ways that ultimately lead to either improper or acceptable disposal. Incineration is a primary method of disposal for wastes containing TPH. Oil spills are frequently captured and treated using various absorbents (e.g., straw, polyurethane foam, activated carbon, peat), gelling agents, dispersants, and mechanical systems. Biodegradation also has been used to treat contaminated soil (OHM/TADS 1985). 

Potentiometric titration UV spectotroscopy Solubility measurements HPLC techniques Capillary zone electrophoresis Foaming activity... 

Alverez Ndnez, F. A., and S. H. Yalkowsky. 1997. Foaming activity and pKa of some surface active compounds. Int. J. Pharm. 151 193-199. 

The average composition of a base wine is given in Table 1. Wines can be viewed as hydroalcoholic solutions containing many organic compounds, some at concentrations as low as a few mg/L, which may show surface activity by themselves (nitrogenous monomers and polymers, e.g. aminoacids, proteins and glycoproteins, etc.) or by association with other compounds (polysaccharides associated with proteins, for example). It is not possible to decide which constituents are actually adsorbed at the surface and which one is the more foam active. 

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