The Influence of Barley Malt Protein Modification on Beer Foam Stability and Their Relationship to the Barley Dimeric α-Amylase Inhibitor-I (BDAI-I) as a Possible Foam-Promoting Protein

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• 作者：Yoshihiro Okada ; Takashi Iimure ; Kiyoshi Takoi ; Takafumi Kaneko ; Makoto Kihara ; Katsuhiro Hayashi ; Kazutoshi Ito ; Kazuhiro Sato ; Kazuyoshi Takeda
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2008
• 出版时间：February 27, 2008
• 年：2008
• 卷：56
• 期：4
• 页码：1458 - 1464
• 全文大小：1128K
• 年卷期：v.56,no.4(February 27, 2008)
• ISSN：1520-5118

文摘

The foam stability of beer is one of the important key factors in evaluating the quality of beer. The purpose of this study was to investigate the relationship between the level of malt modification (degradation of protein, starch, and so on) and the beer foam stability. This was achieved by examining foam-promoting proteins using two-dimensional gel electrophoresis (2DE). We found that the foam stability of beer samples brewed from the barley malts of cultivars B and C decreased as the level of malt modification increased; however, the foam stability of cultivar A did not change. To identify the property providing the increased foam stability of cultivar A, we analyzed beer proteins using 2DE. We analyzed three fractions that could contain beer foam-promoting proteins, namely, beer whole proteins, salt-precipitated proteins, and the proteins concentrated from beer foam. As a result, we found that in cultivar A, some protein spots did not change in any of these three protein fractions even when the level of malt modification increased, although the corresponding protein spots in cultivars B and C decreased. We analyzed these protein spots by peptide mass finger printing using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. As a result, all of these spots were identified as barley dimeric α-amylase inhibitor-I (BDAI-I). These results suggest that BDAI-I is an important contributor to beer foam stability.