Evaluation of the flavour of wheat and rye bread crusts by aroma extract dilution analysis

The neutral and basic volatile compounds of wheat and rye bread crusts were analysed by high-resolution gas chromtography, effluent sniffing and by a dilution technique which revealed the most intense odour compounds. 2-Acetyl-l-pyrroline (roasted, sweet odour) predominated in the wheat bread aroma followed by 2(E)-nonenal (green, tallowy) and 3-methylbutanal (malty). More aroma compounds occurred in the aromagram obtained by the dilution analysis of the rye bread crusts. The most potent odour compounds found were: 3-methylbutanal, 2(E)nonenal, 2,6-dimethyl-3-ethylpyrazine (potato-like) and an unknown compound with a sweet, cereal-like odour.