2009_Book_FoodChemistry

242 3 Lipids
Table 3.59. Aroma compounds formed in oxidative degradation of carotenoids
Precursor a Aroma compound Odor threshold Occurrence
(μ/1, water)
Lycopene (I) 50 Tomato
6-Methyl-5-hepten-2-one
Pseudo ionone
800 Tomato
Dehydrolycopene 380 Tomato
6-Methyl-3,5-heptadien-2-one
α-Carotene (VI) R(+): 0.5–5
S(−): 20–40
α-Ionone
Raspberry, black tea
carrots, vanilla
β-Carotene (VII) 5 Tomato
β-Cyclocitral
β-Ionone
0.007 Tomato, raspberry,
blackberry, passion fruit,
black tea
Neoxanthin (XX) 0.002 Tomato, coffee,
black tea, wine,
beer, honey, apple
β-Damascenone
1,2-Dihydro-1,1,6-trimethylnaphthalene
a Roman numerals refer to the chemical structures presented in 3.8.4.1.
2 Wine, peach,
strawberry
belong to the class of C 13 -norisoprenoides. Other
than β-ionone, α-ionone is a chiralic aroma
compound whose R-enantiomer is present almost
in optical purity in the food items listed in Table
3.59. α- andβ-Damascone (Formula 3.140),
present in black tea are probably derived from
α- and β-carotene. Chiro-specific analysis
(cf. 5.2.4) indicated that α-damascone occurs as
racemate.
(3.140)
The odor thresholds of the R- and S-form (about
1µg/kg, water) differ rarely.