Beverage Foam

In coffee products, such as espresso, a stable foam is an important aspect of overall product quality, in addition to smell, taste, colour, and body [857]. In addition to appearance, a foam layer helps trap coffee aromas, providing a more gradual release. The degree of foaming has been found to increase with the degree of roast and the amount of protein in the coffee, while the stability of the produced foam has been related to the amounts of galactomannan and arabinogalactan [857]. 

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Foaming polystyrene resin prepared by blending with gas deHvers an opaque, low density sheet useful for beverage-bottle and plastic can labels as a water-resistant paper substitute (see Styrene polymers). 

In addition to chemical synthesis and enhanced oil recovery, gaseous carbon dioxide is used in the carbonated beverage industry. Carbon dioxide gas under pressure is introduced into mbber and plastic mixes, and on pressure release a foamed product is produced. Carbon dioxide and inert gas mixtures rich in carbon dioxide are used to purge and fiH industrial equipment to prevent the formation of explosive gas mixtures. 

Plastics. Citric acid and bicarbonate are used as an effervescent blowing agent to foam polystyrene for insulated food and beverage containers replacing blowing agents such as chlorinated fluorocarbons (194—206). 

Process leaks from food and beverage production or wood leachates often produce sugars, colloidal materials, pectins, emulsions, and proteins that cause stable foams in the boiler. These lead to carryover and further steam-condensate line contamination. The temporary use of a demulsifier or defoamer as part of the water treatment program may be of particular benefit, but again the condensate is unsuitable for return to the boiler. Other process leaks include ... 

GA is used as an emulsifier in beverages such as citrus juices, beer, and cola drinks. GA ability to stabilize foams is used in the manufacture of beer and soft drinks. Besides, it can be used for clarifying wines. 

Polyethylene terephthalate) (PET) has become a major synthetic polymer during the past forty years. Significant commercial markets [1] have been developed for its application in textile and industrial fibers, films, and foamed articles, containers for carbonated beverages, water and other liquids, and thermoformed applications (e.g. dual ovenable containers). 

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. 

Cobalt(II) acetate is used for bleaching and drying varnishes and laquers. Other applications are as a foam stahihzer for beverages in sympathetic inks as a mineral supplement in animal feed and as a catalyst for oxidation. It also is used in aluminum anodizing solutions. 

This ability to generate foams finds use in beverages such as ginger beer, shandy, cream soda and cola formulations to improve and standardise heading foam characteristics. 

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