Food Chemistry

15.4 Baked Products 735

Table 15.55.Chemical composition of some types of bread

Bread Water Protein Available Dietary Lipid Minerals
(N× 5 .8) carbohydrates fiber

(%) (%) (%) (%) (%) (%)

White bread 38. 37. 649. 73. 21. 21. 6
White mix bread 37. 66. 247. 74. 61. 11. 5
Rye mix bread 39. 16. 443. 76. 11. 11. 8
Rye bread 38. 16. 245. 86. 51. 01. 6
Rye whole grain bread 42. 06. 838. 78. 11. 21. 5
Crisp bread 7. 09. 466. 114. 61. 42. 3

Table 15.56.Aroma profile of baguette after 1 h and
4ha

Aroma quality Intensitybafter

1h 4h

Roasty 1. 81. 9
Malty 1. 90. 4
Sweet 1. 20
Fatty 1. 02. 3

aAfter leaving the oven the baguettes were cooled for

1 h at room temperature, then wrapped in aluminium
foil and stored at room temperature for another 3 h.
bThe intensity of each aroma quality was evaluated

from 0–3 (strong). Average values of five testers.

aroma profile are greatly reduced and the fatty
note predominates (Table 15.56). These changes
are caused by the differences in the evaporation
rates of the aroma substances. To determine these
rates, the amounts of odorants which evaporate
from a baguette in 15 min are collected at the
times given in Table 15.58 and measured. The
results in Table 15.58 show the evaporation rates
of the malty smelling aldehydes methylpropanal,
2- and 3-methylbutanal decrease continuously in
accordance with the changes in the aroma profile.
This also results in the fact that odorants like the
fatty smelling (E)-2-nonenal are more detectable
with time. However, the intensity of the fatty
note also increases because the evaporation
rate of (E)-2-nonenal increases (Table 15.58),
possibly due to the decomposition of the linoleic
acid hydroperoxides formed during baking.

Table 15.57.Odorants of the baguette crusta

Compound Concen- Aroma-

tration valueb

(μg/kg)

Methylpropanal 1750 31

2-Methylbutanal 962 18

3-Methylbutanal 335 26

Methional 29 107

Dimethyl trisulfide 5. 159

2,3-Butandione 1320 203

2-Acetyl-1-pyrroline 16 2191

2-Ethyl-3,5-dimethylpyrazine 3. 219

Hexanal 214 7

1-Octen-3-one 6. 6 150

(E)-2-Nonenal 87 164

(E,E)-2,4-Decadienal 56 21

aAfter leaving the oven the baguettes were cooled for

1 h at room temperature, then the crust was separated,

frozen with liquid nitrogen and analyzed.

bOn the basis of the odor threshold of the compound

on starch.

2-Acetyl-1-pyrroline evaporates uniformly (Ta-

ble 15.58); the intensity of the roasty note is

correspondingly stable during storage for 4 hours

(Table 15.56). The losses of this odorant in the

white bread crust on longer storage is shown

in Table 15.59.

The aroma is influenced by the recipe but also by

the fermentation, e. g., theStreckeraldehydes in-

crease and those from lipid peroxidation decrease

if the dough matures at lower temperatures (Ta-

ble 15.60). An extension of the kneading process