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Abstract

In bright beers, the formation of permanent haze is a serious quality
problem that places limitations on the storage life of the product. From
silica gel, used for the colloidal stabilization of beer, a silica eluent
(SE) protein fraction was isolated and an antibody raised against this
fraction. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis
(SDS-PAGE) immunoblot analysis using the SE antiserum detected a
range of protein bands in barley, malt, beer, and haze. Interestingly, a
polymorphism was observed in some barley varieties that contained an
~12,000-molecular-weight band (SE +ve), while in other varieties, this
band was absent (SE –ve). Pilot brewing trials found that beer brewed
from SE –ve varieties formed less haze in haze force testing trials (5
days at 55°C/1 day at 0°C) than did beer produced from SE +ve varieties.
The interaction between the presence/absence of the SE protein
and controlled-atmosphere brewing by brewing under nitrogen or air
was also investigated. Surprisingly, the application of a nitrogen-rich atmosphere
produced beer that was less stable compared with that produced
when brewing under a normal atmosphere. Filtration trials showed
that the colloidal stability of beer could be influenced by the filtration
process. The removal of the SE protein and other proteins during filtration
from beer brewed with an SE +ve malt variety, along with a reduction
in the level of total protein as measured by Bradford, resulted
in improved colloidal stability. Combined, these investigations are discussed
in terms of brewers’ options for extending the colloidal stability
of their beer and optimizing the colloidal stabilization treatments.

Item Type:	Article
Authors/Creators:	Robinson, LH and Evans, DE and Kaukovirta-Norja, A and Vilpola, A and Aldred, P and Home, S
Keywords:	beer aging, brewing, colloidal stability, filtration, haze, malt, protein
Journal or Publication Title:	Master Brewers Association of the Americas, Technical Quarterly
ISSN:	1558-0628
Item Statistics:	View statistics for this item

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