POTENT ODORANTS OF RYE BREAD CRUST - DIFFERENCES FROM THE CRUMB AND FROM WHEAT BREAD CRUST

Aroma extract dilution analyses revealed twenty-eight odorants in fresh rye bread crust and twenty in its crumb. On the basis of high flavour dilution factors, methional (boiled potato), 3-methylbutanal (malty), (E)-2-nonenal (green, tallowy). (E,E)-2.4-decadienal (fatty) and acetic acid (sour, pungent) belonged to the potent odorants of the crust. and phenylacetaldehyde, (E)-2-nonenal and (E,E)-2,4-decadienal to those of the crumb. Compared with the crust, especially the odour activities of methional, 3-methylbutanal, 2-ethyl-3,5-dimethylpyrazine and 4-hydroxy-2,5-dimethyl-3(2H)-furanone were significantly lower in the crumb. Calculation of the odour activity values (OAV, ratio of concentration to odour threshold) indicated that the higher OAV of methional in the rye crust and the higher OAV of 2-acetyl-1-pyrroline in the wheat bread crust mainly contributed to the flavour difference of the two kinds of bread.