Photosensitized E/Z isomerization of (all-E)-lycopene aiming at practical applications.
Photoisomerization of (all-E)-lycopene to the corresponding Z-isomers was investigated under visible to middle-infrared light irradiation in the presence of several sensitizers, including edible ones. Highly purified (all-E)-lycopene from tomato paste was isomerized to Z-isomers to the extent of 46.4-57.4% after irradiation with the sensitizers for 60 min in acetone, in which a thermodynamically stable isomer of (5Z)-lycopene was predominantly generated, whereas kinetically preferable (9Z)- and (13Z)-lycopenes were dominant without sensitizer. Examination of the time course of photoisomerization demonstrated that the highest isomerization efficiency (80.4%) was attained using erythrosine as the sensitizer under 480-600 nm light irradiation in hexane for 60 min, a protocol that successfully suppressed the degradation of lycopene. (5Z)-Lycopene, reported as a more bioavailable isomer, was again predominantly produced with erythrosine and rose bengal in each solvent.
Research and Development Division, Kagome Company, Ltd. , Nishitomiyama, Nasushiobara 329-2762, Japan.
Masaki
M
Honda
Haruyuki
H
Igami
Takahiro
T
Kawana
Kento
K
Hayashi
Munenori
M
Takehara
Yoshinori
Y
Inoue
Chitoshi
C
Kitamura
D000975:Antioxidants / Q000737:chemistry; D002338:Carotenoids / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D005511:Food Handling / Q000379:methods; D007536:Isomerism; D000077276:Lycopene; D018551:Solanum lycopersicum / Q000737:chemistry; D017319:Photosensitizing Agents / Q000737:chemistry*
D000975:Antioxidants; D017319:Photosensitizing Agents; D002338:Carotenoids; D000077276:Lycopene
erythrosine; lycopene; photoisomerization; rose bengal; sensitizer