Chemistry of Bread Aroma: A Review

The roles of ingredient formulation, dough fermentation, and baking conditions on bread aroma are reviewed. More than 540 volatile compounds have been reported in bread. However, only a relative small portion of the volatile compounds in bread contribute to the desirable aroma properties. The primary odorants reported to contribute to the flavor of wheat bread crust were 2-acetyl-1-pyrroline, (E)-2-nonenal, 3-methylbutanal, 2,3-butanedione, methional, and (Z)-2-nonenal, whereas for bread crumb, (E)-2-nonenal, (E,Z)-2,6-nonadienal, (E,E)-2,4-decadienal, 2,3-butanedione, methional, 1-octen-3-ol, and (E,E)-2,4-nonadienal were identified. One compound, in particular, 2-acetyl-1-pyrroline has been suggested to be the key odorants of the crust and is considered to be responsible for the cracker-like odor properties. These compounds are primarily generated during thermal processing but also influence by ingredient composition and fermentation conditions.