Method of selecting barley variety, barley beta-amylase gene and process for producing malt alcoholic beverage

Abstract

A method of selecting a barley variety comprising: a heat treatment step of heat-treating a crude enzyme solution extracted from a seed of a barley (e.g., at 57.5° C. for 30 minutes); an activity-determining step of determining the enzyme activity of β-amylase in the crude enzyme solution heat-treated; and a selection step of selecting the barley variety containing a β-amylase having a residual activity of from 85 to 90% as a result of the activity determination.

1 . A method of selecting a barley variety, comprising:
 amplifying a β-amylase structural gene region in the genomic DNA extracted from a barley;   cleaving the β-amylase structural gene amplified in the gene amplification step with a restriction enzyme and detecting a gene fragment having a predetermined number of bases; and   selecting the barley variety based on the base number of the gene fragment detected during said cleaving and detecting.   
     
     
         2 . The method according to  claim 1 , wherein the gene region to be amplified is a gene region comprising the second exon of the barley β-amylase gene in the gene amplification step and the restriction enzyme is MspI in the gene detection step. 
     
     
         3 . A structural gene for barley β-amylase gene comprising the sequence of SEQ ID NO:1. 
     
     
         4 . A nucleic acid comprising a part of the structural gene for barley β-amylase gene according to  claim 3 . 
     
     
         5 . A process for producing a malt alcoholic beverage, comprising:
 selecting a barley variety,   malting the selected barley to obtain a malt,   saccharizing the malt to obtain a wort,   adding a yeast to the wort; and subsequently   fermenting the wort, thereby obtaining the malt alcoholic beverage.   
     
     
         6 . The method of  claim 5 , wherein the selecting comprises:
 heating a crude enzyme solution extracted from a seed of a barley,   determining the enzyme activity of a β-amylase in the heat-treated crude enzyme solution, and   selecting a barley variety comprising a β-amylase having a residual activity of from 85 to 90% as a result of the activity determination compared to an unheated control.   
     
     
         7 . The method of  claim 6 , wherein said heating of the crude enzyme solution occurs at a predetermined temperature of 55 to 58° C. and for a time of 10 to 60 minutes. 
     
     
         8 . The method of  claim 5 , wherein the selecting comprises:
 amplifying a β-amylase structural gene region in the genomic DNA extracted from a barley;   cleaving the β-amylase structural gene amplified in the gene amplification step with a restriction enzyme and detecting a gene fragment having a predetermined number of bases; and   selecting the barley variety based on the base number of the gene fragment detected during said cleaving and detecting.   
     
     
         9 . The method of  claim 8 , wherein the gene region to be amplified is a gene region comprising the second exon of the barley β-amylase gene in the gene amplification step and the restriction enzyme is MspI in the gene detection step. 
     
     
         10 . A beverage, comprising:
 the malt alcoholic beverage as produced by  claim 5 .