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.
Original language | English |
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Pages (from-to) | 353-362 |
Journal | MBAA Technical Quarterly |
Volume | 41 |
Issue number | 4 |
Publication status | Published - 2004 |
MoE publication type | A1 Journal article-refereed |
Keywords
- beer aging
- brewing
- colloidal stability
- filtration
- haze
- malt
- proteins