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

Aroma extract dilution analyses revealed twenty-eight odorants in fres h rye bread crust and twenty in its crumb. On the basis of high flavou r dilution factors, methional (boiled potato), 3-methylbutanal (malty) , (E)-2-nonenal (green, tallowy). (E,E)-2.4-decadienal (fatty) and ace tic acid (sour, pungent) belonged to the potent odorants of the crust. and phenylacetaldehyde, (E)-2-nonenal and (E,E)-2,4-decadienal to tho se of the crumb. Compared with the crust, especially the odour activit ies of methional, 3-methylbutanal, 2-ethyl-3,5-dimethylpyrazine and 4- hydroxy-2,5-dimethyl-3(2H)-furanone were significantly lower in the cr umb. Calculation of the odour activity values (OAV, ratio of concentra tion 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 k inds of bread.