Genetic basis of barley contributions to beer flavor

13 Pags.- 1 Fig.- 3 Tabls. © 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.Barley malt is critical for the malting, brewing, and distilling industries, as it is one of the main ingredients of beer and some types of spirits. There is growing evidence that barley genotype - via malt - can impact the flavors of beers and spirits. However, information on the barley genes involved in these flavors is lacking. Therefore, we used quantitative trait locus (QTL) mapping of malt quality traits, beer sensory descriptors and metabolic compounds on a biparental population of doubled haploids derived from the cross of the cultivars Golden Promise and Full Pint. Putative candidate genes for QTLs were identified by alignment with the reference barley genome sequence. There were thirty-seven QTLs across all chromosomes except 4H, with three QTL clusters located on 3H (1 cluster) and 5H (2 clusters: mid-5H and end-5H). Those “hotspots” contained QTLs for multiple phenotypes. Several candidate genes that regulate plant metabolism were identified within the QTLs and included HvAlaAT, HvDep1, HvMKK3, HvGA20ox1 and HvGA20ox2. These genes are involved in seed dormancy and plant height. Alleles at these loci, and perhaps at physically linked loci, can have key downstream effects on malting quality, beer flavor, and abundance of volatile metabolites.Research at Oregon State University was supported by the Agricultural Research Foundation Barley Progress Fund. At Colorado State University, research was supported by CSU's College of Agricultural Sciences, with partial support from the American Malting Barley Association.Peer reviewe

Genetic and metabolomic analyses of barley and cowpea: implications on quality and nutrition of finished foods

2021 Fall.Includes bibliographical references.The finished foods of a cereal (barley) and a legume (cowpea) were subjects of this thesis and analyzed in two separate studies. High quality barley that meets malting standards, is economically worth billions each year to the malting and brewing industry. The prevalence of craft brewing has been on the rise and with that, an increased interest in understanding the basis of beer flavor. Malt has been the subject of most research on beer flavor, and currently there is a lack of understanding on the contributions that the barley variety has to product flavor. The second crop that was subject of this thesis is cowpea. Cowpea is a nutritious food, that grows well in sub-Saharan Africa, where malnutrition is prevalent. It is well adapted to the resource-poor farming practices common in these regions, and highly valued as a food security crop. Despite the known health benefits, potential to alleviate malnutrition, and use in nutritional studies, there are no biomarkers identified for cowpea and its metabolic profile is currently not well characterized. The research goals of this thesis are broken down by crop. Regarding barley, the goals were to 1) test the hypothesis that barley genotype contributes to beer flavor, 2) to identify regions of the genome that control traits associated with flavor, and 3) identify candidate genes that control traits associated with flavor. Regarding cowpea, the goals were to 1) characterize the metabolic profile of three cowpea flours from varieties commonly consumed in sub-Saharan Africa (Ghana, specifically), and 2) test the hypothesis that there are metabolites unique to cowpea (and cowpea varieties). Metabolomic approaches were applied to both crops as finished foods, with additional genetic analysis of barley. We concluded that barley genotype does contribute to beer flavor, and that cowpea has distinct and characterizable metabolomic differences from other legumes. In barley, QTLs (quantitative trait loci) for malt quality, beer sensory, and metabolite traits were mapped, and candidate genes identified. The results of this study set a foundation for future genetic and breeding efforts surrounding barley and beer flavor, allowing for integration of various quality attributes. In cowpea, comparisons were made between cowpea, pigeon pea (another legume common to sub-Saharan Africa), and common bean on two non-targeted mass spectrometry platforms. Comparisons between the legumes illuminated metabolites that were either common to, or unique to each legume type or variety. The annotated metabolites from both analyses were from a diverse set of classifications and metabolic pathways, many with numerous known nutritional benefits. The metabolomic profiling of cowpea (and cowpea varieties) will allow for easier identification of nutritional biomarkers in future feeding studies