Chemical markers for bitterness in wheat bread

The manufacture of high-quality whole-grain products is challenged by poor flavour attributes, such as excessive bitterness. In a recent study our group characterized eight compounds that contributed to the bitterness of a whole-wheat bread sample. The goal of this study was to investigate the chemical profile of these bitter compounds in relation to the perceived bitterness of four commercial whole wheat breads and one refined wheat bread. Highly significant correlations (α=0.01) were observed between the perceived bitterness in the crust and the quantity of 5-(hydroxymethyl)furfural (r ²=0.93) and 2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one (r ²=0.95). In the crumb, the bitterness was correlated with the amount of l-tryptophan (r ²=0.91). In summary, both Maillard- and fermentation-derived compounds were identified as potential chemical markers to predict bitterness of whole-wheat bread.