Barley for production of flavor-stable beverage
According to the invention, there is provided null-LOX-1 barley and plant products produced thereof, such as malt manufactured by using barley kernels defective in synthesis of the fatty acid-converting enzyme lipoxygenase-1. Said enzyme accounts for the principal activity related to conversion of linoleic acid into 9-hydroperoxy octadecadienoic acid, a lipoxygenase pathway metabolite, which—through further enzymatic or spontaneous reactions—may lead to the appearance of trans-2-nonenal. The invention enables brewers to produce a beer devoid of detectable trans-2-nonenal-specific off-flavors, even after prolonged storage of the beverage.
1. A barley plant or a portion of said plant, comprising mutated LOX-1 protein lacking all or at least a portion of amino acids 520 to 862 of wild type barley LOX-1 (SEQ ID NO: 3 or 7), wherein said plant exhibits null LOX-1 activity.
2. A barley plant or portion of said plant comprising mutated LOX-1 protein truncated at or between amino acids 378 and 665 of wild-type barley LOX-1 (SEQ ID NO: 3 or 7), wherein said plant exhibits null LOX-1 activity.
3. The barley plant or portion according to claim 2 , wherein said mutated LOX-1 protein consists essentially of amino acids 1-378 of wild-type barley LOX-1 (SEQ ID NO: 3 or 7).
4. The barley plant or portion according to claim 3 , wherein said mutated LOX-1 protein has the amino acid sequence of SEQ ID NO: 4 or 8.
5. The barley plant or portion according to claim 2 , wherein said mutated LOX-1 protein is encoded by a gene that comprises a premature stop codon at or between nucleotides 2311 and 3574 of wild-type genomic barley lox-1 (SEQ ID NO: 1 or 5).
6. The barley plant or portion according to claim 5 , wherein said mutated LOX-1 protein is encoded by a gene that comprises a stop codon at nucleotides 3572-3574 of wild-type genomic barley lox-1 (SEQ ID NO: 1 or 5).
7. The barley plant or portion according to claim 5 , wherein said mutated LOX-1 protein is encoded by the nucleic acid sequence of SEQ ID NO: 2 or 6.
8. The barley plant or portion according to claim 1 , wherein said plant has ATCC accession No. PTA-5847 or PTA-5584.
9. The barley plant or portion according to claim 1 , wherein said portion comprises a kernel.
10. The barley plant or portion according to claim 1 , wherein said portion comprises an embryo.
11. The barley plant or portion according to claim 1 , wherein said LOX-1 activity is determined in homogenized embryo tissue of M3 or M4 plant kernels.
12. A malt composition comprising malted kernels of the plant of claim 1 .
13. A malt composition comprising malted kernels of the plant of claim 6 .