43219-98-3Relevant academic research and scientific papers
Changes of Lemon Flavor Components in an Aqueous Solution during UV Irradiation
Iwanami, Yuko,Tateba, Hideki,Kodama, Nobuko,Kishino, Katsumi
, p. 463 - 466 (2007/10/03)
A lemon flavor composed of lemon oil, water (pH 6 phosphate buffer), and ethanol, and the lemon-flavored drink were irradiated with UV light. Citral (1 and 2), which is one of the most important components expressing the typical lemon-like odor, significantly decreased with Z-E isomerization and there appeared 2-(3-methyl-2-cyclopenten-1-yl)-2-methylpropionaldehyde (6), trans-1,3,3-trimethylbicyclo[3.1.0]hexane-1-carboxaldehyde (7), cis-1,3,3-trimethylbicyclo[3.1.0]hexane-1-carboxaldehyde (8), (1,2,2-trimethyl-3-cyclopenten-1-yl)acetaldehyde (9), α-campholenealdehyde (10), photocitral A (8), epiphotocitral A (4), and photocitral B (5). New compounds of aldehyde 9, 6 and 10, were newly identified as photoreaction products of citral. Limonene, terpinolene, and nonanal decreased, while p-cymene increased after UV irradiation. Other components, such as sesquiterpene hydrocarbons, citronellal, linalool, and terpineols, were only slightly changed. These results suggested that citral is a more UV-unstable component in lemon flavor and the photolysis of citral could affect other components in lemon flavor during UV irradiation.
PHOTOCHEMISCHE REAKTIONEN
Yoshioka, Michikazu,Ishii, Keitaro,Wolf, Hans Richard
, p. 571 - 587 (2007/10/02)
On 1n,?*-excitation (λ>347 nm) citral (5) and the methyl ketone 10 isomerize to compounds A (7, 19) and B(6, 20), whereas the phenyl ketone 11 changes into the isomer 24 of type E. evidence is given that the conversion to A and B may arise from the 3n,?*-state of the 2,6-diene-carbonyl compounds.On 1p,?*-excitation (λ=254 nm) 5 and 10 yield the isomers A (7, 19) and D (18, 22), but no products of type B.Futhermore, conversion of 10 to the isomer 21 of type C is observed.Selective 1?,?*-excitation (λ=254 nm) as well as selective 1n,?*-excitation (λ>347 nm) of the 2,7-diene-carbonyl compounds 12 and 13 give rise to isomerization to the compounds F (25, 28), exclusively.The intramolecular (2+2)-photocycloadditions are shown to be triplet processes.UV.-irradiation (λ>280 nm) of compounds F (25, 28) furnishes the isomeric products G (26, 29) which photoisomerize to oxetanes of type H (27, 30).
