Beer, haze prevention

Chemical analysis of haze materials isolated from a beverage must be interpreted with caution because composition is often not well-related to cause. For example, beer hazes typically contain a high proportion of carbohydrate, with a modest amount of protein, and little polyphenol (Belleau and Dadic, 1981 Siebert et al., 1981). In order to prevent or delay haze formation, however, it is not necessary or helpful to remove carbohydrate. Reducing the amount of either protein or polyphenol typically has that effect. As a result, it appears that the large amount of carbohydrate found in the haze was coagulated with or adhered in some way to the protein-polyphenol haze backbone. 

Chillproofers are added to freshly brewed beers to prevent the formation of haze upon cold storage. Papain-based enzymes have been used as chillproofers and their addition have to be monitored carefully, as overdosage results in flat beer. According to Skerritt et al (146), enzymatic methods currently used lack sensitivity or are slow and tedious. They have developed a polyclonal antibody-based kit for determination of these chillproofers. 

Ahrenst-Larsen B and Erdal K. Anthocyanogen-free barley—a key to natural prevention of beer haze. Proceedings of the 17th Congress of the European Brewery Convention, Berhn, 1979 631-644. ISSN 0367-018X. 

Tannins Astringent condensed polyphenolic compounds present in some cereals such as bird-resistant sorghums that are antinutritional because they bind digestive enzymes and dietary proteins lowering feed efficiency. Tannins are also antimicrobial and prevent grain from sprouting in the field. Today, tannins are viewed as potent antioxidants and nutraceuticals. The tannins associated with hops bind proteins, decreasing beer haze and, upon oxidation, form colored compounds necessary in beer. 

The crospovidones are easily compressed when anhydrous but readily regain their form upon exposure to moisture. This is an ideal situation for use in pharmaceutical tablet disintegration and they have found commercial appHcation in this technology. PVP strongly interacts with polyphenols, the crospovidones can readily remove them from beer, preventing subsequent interaction with beer proteins and the resulting formation of haze. The resin can be recovered and regenerated with dilute caustic. 

Lopez, M. and Edens, L. (2005). Effective prevention of chill-haze in beer using an acid proline-specific endoprotease from Aspergillus niger.. Agric. Food Chem. 53, 7944 7949. McCarthy, S. L., Melm, G. D., and Pringle, A. T. (2005). Comparison of rapid physical stability tests. ]. Am. Soc. Brew. Chem. 63, 69-72. 

Another typical enzyme application in the production of beer is the use of proteases, such as papain or laccases in chill-proofing, which is the prevention of haze formation that can occur at low temperatures during or after the maturation of beer. Finally, to... 

Permits fermentation by converting starch to fermentable sugar Prevents chill haze in beer (a complex which includes protein, carbohydrates and tannins)... 

Use Meat tenderizer, other food industries (mainly to prevent protein haze on chilling beer), tobacco, pharmaceutical, cosmetic, leather, textiles. 

Prevention of chill haze in beer resulting from protein—phenolic interactions... 

Three other plant enzymes, papain, bromelain, and to a lesser extent ficin, have found acceptance in the food industry as proteases. Papain is derived from the latex of the fruit, leaves, and trunk of Carica papaya, and bromelain from the fruit and stems of pineapple plants. These enzymes are used to prevent the hazing of beer when chilled (Chill-Proofing) by modifying the protein. Other applications for these plant proteases are in meat tenderizers and digestive aids. Ficin from the latex of Ficus carica is used to a much lower extent, perhaps because of its marked action on native protein and difficult handling. Proteases from Aspergillus Jlavus-oryzae, and to a lesser extent from Bacillus subtilis, have been used to replace and supplement these plant proteases in all applications, but papain continues to have the widest acceptance. 

Phosphate additives are especially useful in the production of alcoholic beverages. This is because of their ability to form stable soluble complexes with troublesome Fe +, Cu % Ca and other cations which need not then be removed. Polyphosphates prevent clonding or hazing in wine and beer. 

Proteases have found practical application in various food and other technologies for instance, rennin is used in the dairy industry for the manufacture of hard cheeses, while plant proteases, such as papain, are employed in the prevention of protein hazes in beer. 

The addition of 20-30 mg/1 ascorbic acid prevents the formation of colloidal turbidity (called chill haze) in beer, and also prevents adverse changes in flavour due to the oxidation that occurs during pasteurisation and storage. The use of ascorbic acid in winemaking can reduce the amount of sulfur dioxide used for fumigation. 

The earliest practical uses of papain were medicinal, e.g., in the treatment of dyspepsia and intestinal worms (86). Today most of the papain is consumed by various industries. Thus, it is used commercially for tenderizing meat, in the textile industry to prevent wool shrinkage, in the brewing industry to prevent oxidation and chill hazes in beer, in the tanning industry to bate skins and hides, and..in the manufacture of chewing gum. It is difficult to estimate the world consumption however, the United States alone imports about 500,000 pounds of crude papain annually (161). 

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