Enzymatic Hydrogenation of trans-2-Nonenal in Barley
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- 作者：Gustav Hambraeus and Nils Nyberg
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2005
- 出版时间：November 2, 2005
- 年：2005
- 卷：53
- 期：22
- 页码：8714 - 8721
- 全文大小：393K
- 年卷期：v.53,no.22(November 2, 2005)
- ISSN：1520-5118
文摘
Conversion of undesirable, taste-active compounds is crucial for using barley as a suitable raw materialfor beer production. Here, ALH1, a barley alkenal hydrogenase enzyme that reduced the 
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ta2.gif" BORDER=0 ALIGN="middle">-unsaturated double bond of aldehydes and ketones, was found to convert trans-2-nonenal (T2N), amajor contributor to the cardboard-like flavor of aged beer. Although the physiological function ofALH1 in barley development remains elusive, it exhibited high specificity with NADPH as a cofactorin the conversion of several oxylipins-including T2N, trans-2-hexenal, traumatin, and 1-octen-3-one. ALH1 action represents a previously unknown mechanism for T2N conversion in barley. Additionalexperimental results resolved the genomic sequence for barley ALH1, as well as the identification ofa paralog gene encoding ALH2. Interestingly, T2N was not converted by purified, recombinant ALH2.The possibility to enhance ALH1 activity in planta is discussed-not only with respect to thephysiological consequences thereof-but also in relation to improved beer quality.Keywords: Malt; beer; taste stability; alkenal hydrogenase; nonenal; 1-octen-3-one
,ta2.gif" BORDER=0 ALIGN="middle">-unsaturated double bond of aldehydes and ketones, was found to convert trans-2-nonenal (T2N), amajor contributor to the cardboard-like flavor of aged beer. Although the physiological function ofALH1 in barley development remains elusive, it exhibited high specificity with NADPH as a cofactorin the conversion of several oxylipins-including T2N, trans-2-hexenal, traumatin, and 1-octen-3-one. ALH1 action represents a previously unknown mechanism for T2N conversion in barley. Additionalexperimental results resolved the genomic sequence for barley ALH1, as well as the identification ofa paralog gene encoding ALH2. Interestingly, T2N was not converted by purified, recombinant ALH2.The possibility to enhance ALH1 activity in planta is discussed-not only with respect to thephysiological consequences thereof-but also in relation to improved beer quality.Keywords: Malt; beer; taste stability; alkenal hydrogenase; nonenal; 1-octen-3-one