2009_Book_FoodChemistry

362 5 Aroma Compounds
Table 5.18. Furanones in food
Structure Substituent/trivial name or Aroma Occurrence
trade name (odor threshold quality
in µg/kg, water)
A. 3(2H)-Furanones
4-Hydroxy-5-methyl
Norfuraneol (nasal:
23,000)
Roasted
chicory-like,
caramel
Meat broth
4-Hydroxy-2,5-dimethyl
Furaneol
(nasal: 60;
retronasal: 25)
Heat-treated
strawberry,
pineapple-like,
caramel
cf. Table 5.20
2-(5)-Ethyl-4-hydroxy-
5-(2)-methyl a
Ethylfuraneol
(nasal: 7.5)
Sweet,
pastry,
caramel
Soya sauce
Emmental
cheese
4-Methoxy-2,5-dimethyl
Mesifuran (nasal: 3400)
Sherry-like
Strawberry,
raspberry b
B. 2(5H)-Furanones
3-Hydroxyl-4,5-dimethyl
Sotolon
(nasal, R-form 90,
recemate, retronasal: 3)
Caramel,
protein
hydrolysate
S-form 7
Coffee, sherry,
seasonings,
fenugreek
seeds
5-Ethyl-3-hydroxy-
Abhexon
hydrolysate
(nasal: 30, retronsal: 3)
Caramel,
4-methyl
protein
Coffee,
seasonings
a Of the two tautomeric forms, only the 5-ethyl-4-hydroxy-2-methyl isomer is aroma active.
b Arctic bramble (Rubus arcticus).
an aroma quality similar to that of sotolon and
is formed by aldol condensation of 2,3-pentanedione
and glycol aldehyde, which can be obtained
from the Maillard reaction, or by aldol condensation
of 2 molecules of α-oxobutyric acid,
a degradation product of threonine (Fig. 5.16).
Quantitative analysis of furanones is not very
easy because due to their good solubility in water,
they are extracted from aqueous foods with
poor yields and easily decompose, e. g., sotolon
(cf. Formula 5.6). Correct values are obtained
by IDA.