Genetic and environmental effects on the composition and properties of lipids in wheat flour

Being valued at £3.4 billion per annum and producing 4 billion loaves a year, the UK breadmaking industry is vast. Due to this, much research has focused on improving breadmaking quality. Breadmaking quality is significantly affected by flour lipids which play a crucial role at various stages of breadmaking. For example, during the initial stages of dough development, lipids can adsorb to the surface of gas bubbles, stabilizing them, allowing air retention in the dough. This stability helps provide the loaf volume, crumb structure and quality associated with UK bread. Despite the importance of lipids in breadmaking, limited research has been carried out on grain and flour lipids. No evidence of significant genetic control of wheat grain lipids had been reported, and wheat lipids were not considered a suitable target for improving breadmaking quality. Therefore, in this project, six wheat lines grown under three nitrogen conditions in 2012-13 were milled and analysed using a ‘lipodomics platform.’ This provided flour lipid profiles, allowing the use of multivariate statistics to identify the effects of genotype, environment or GxE effects on individual lipid species. A previous project identified QTL (Quantitative Trait Loci) for milling and baking quality parameters using a doubled haploid (DH) population from a cross between two UK breadmaking cultivars, Malacca and Hereward. Four robust QTLs for gas cell number and loaf volume located on chromosomes 1B, 4D, 6A and 7A were selected, and near isogenic lines (NILs) with a good or poor quality allele in the Malacca background were obtained. Lipidomic analysis across two years identified lipids associated with these alleles, allowing the correlation of the lipid profile with the good or poor quality alleles at the four loci. The functional significance of any differences in lipid composition was explored by extracting dough liquor and analysing their surface properties