TY - JOUR
T1 - Identification of novel haze-active beer proteins by proteome analysis
AU - Iimure, Takashi
AU - Nankaku, Nami
AU - Watanabe, Megumi
AU - Hirota, Naohiko
AU - Tiansu, Zhou
AU - Kihara, Makoto
AU - Hayashi, Katsuhiro
AU - Ito, Kazutoshi
AU - Sato, Kazuhiro
PY - 2009/1
Y1 - 2009/1
N2 - Colloidal haze reduces beer quality considerably. Four haze samples were analyzed by two-dimensional gel electrophoresis (2DE) in order to identify haze-active proteins. Several protein spots were observed in all of the four haze samples. Using mass spectrometry analysis followed by a database search identified these spots as barley dimeric alpha-amylase inhibitor (BDAI-1), CMb component of tetrameric alpha-amylase inhibitor (CMb) and trypsin inhibitor CMe precursor (CMe). These proteins were considered to be haze-active. Since haze-active proteins are adsorbed by silica gel in the beer filtration process, we eluted proteins adsorbed onto silica gel (PAS) and identified their species. These major PAS were identified as protein Z4, protein Z7 and trypsin/amylase inhibitor pUP13 (TAI), rather than BDAI-1, CMb and CMe. Furthermore, we analyzed proline compositions in the beer proteins, PAS and the haze proteins. Consequently, we found that the proline compositions of PAS were higher (ca. 20 mol%) than those in the beer proteins (ca. 10 mol%), although those of the haze-active proteins such as BDAI-1, CMb and CMe were 6.6-8.7 mol%. Our results suggest that BDAI-1, CMb and CMe are not predominant haze-active proteins, but growth factors of beer colloidal haze.
AB - Colloidal haze reduces beer quality considerably. Four haze samples were analyzed by two-dimensional gel electrophoresis (2DE) in order to identify haze-active proteins. Several protein spots were observed in all of the four haze samples. Using mass spectrometry analysis followed by a database search identified these spots as barley dimeric alpha-amylase inhibitor (BDAI-1), CMb component of tetrameric alpha-amylase inhibitor (CMb) and trypsin inhibitor CMe precursor (CMe). These proteins were considered to be haze-active. Since haze-active proteins are adsorbed by silica gel in the beer filtration process, we eluted proteins adsorbed onto silica gel (PAS) and identified their species. These major PAS were identified as protein Z4, protein Z7 and trypsin/amylase inhibitor pUP13 (TAI), rather than BDAI-1, CMb and CMe. Furthermore, we analyzed proline compositions in the beer proteins, PAS and the haze proteins. Consequently, we found that the proline compositions of PAS were higher (ca. 20 mol%) than those in the beer proteins (ca. 10 mol%), although those of the haze-active proteins such as BDAI-1, CMb and CMe were 6.6-8.7 mol%. Our results suggest that BDAI-1, CMb and CMe are not predominant haze-active proteins, but growth factors of beer colloidal haze.
KW - Barley
KW - Beer colloidal haze
KW - Proteome analysis
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U2 - 10.1016/j.jcs.2008.08.004
DO - 10.1016/j.jcs.2008.08.004
M3 - Article
AN - SCOPUS:57149085040
VL - 49
SP - 141
EP - 147
JO - Journal of Cereal Science
JF - Journal of Cereal Science
SN - 0733-5210
IS - 1
ER -