174 J. Agric. Food Chem., Vol. 55, No. 1, 2007
Jung et al.
light exposure as in the phosphate buffer. Yet, the 2,3-
butanedione content (0.82 ( 0.01 µg/mL) formed in the purified
water was somewhat lower than that (0.57 ( 0.10 µg/mL) in
the phosphate buffer of pH 6.5. The result showed that sodium
phosphate did not affect the mechanism for the formation of
(9) Kim, H.; Kirschenbaum, L. J.; Rosenthal, I.; Riesz, P. Photo-
sensitized formation of ascorbate radicals by riboflavin: an ESR
study. Photochem. Photobiol. 1993, 57, 777-784.
10) Edwards, A. M.; Bueno, C.; Saldano, A.; Silva, E.; Kassab, K.;
Polo, L.; Jori, G. Photochemical and pharmacokinetic properties
of selected flavins. J. Photochem. Photobiol., B 1999, 48, 36-
(
2,3-butanedione, but slightly accelerated its formation. We also
4
1.
tested the effects of riboflavin contents in the sodium phosphate
buffer (0.1 M, pH 6.5) on the 2,3-butanedione formation. Lower
riboflavin concentration in buffered solution induced the
significantly lower content of 2,3-butanedione in the solution
after 12 h light exposure. The concentrations of 2,3-butanedione
formed from 0.25 mM riboflavin and 0.5 mM riboflavin in
sodium phosphate buffer solution (pH 6.5) were 0.82 ( 0.01
and 0.53 ( 0.06 µg/mL.
In conclusion, riboflavin in a buffer solution under light
produced a buttery odor. The buttery odor compound was
positively identified as 2,3-butanedione by a combination of
gas chromatographic retention time, mass spectrum, and odor
evaluation with authentic 2,3-butanedione. Sodium azide re-
duced the formation of 2,3-butanedione from riboflavin solution
under light. The 2,3-butanedione was formed by the reaction
between singlet oxygen and riboflavin. The detailed mechanism
for the formation of 2,3-butanedione from riboflavin and singlet
oxygen under light was presented. The buttery odor compound
from riboflavin under light could affect the flavor quality of
foods containing riboflavin under light. This paper reports the
formation of buttery odor 2,3-butanedione formed from ribo-
flavin under light for the first time. The previously identified
compounds formed from riboflavin under light are nonvolatile
lumichrome and lumiflavin (19). The formation of nonvolatile
lumichrome and lumiflavin and volatile 2,3-butanedione from
riboflavin solution under light may explain the rapid destruction
of riboflavin in foods under light.
(
11) Criado, S.; Castillo, C.; Yppolito, R.; Bertolotti, S.; Garcia,
N. A. The role of 4- and 5-aminosalicylic acids in a riboflavin-
photosensitized process. J. Photochem. Photobiol., A 2003, 155,
1
15-118.
(
12) Huang, R.; Choe, E.; Min, D. B. Effects of riboflavin photo-
sensitized oxidation on the volatile compounds of soymilk.
J. Food Sci. 2005, 69, C733-C738.
13) Rosenthal, A.; Deliza, R.; Cabral, L. M. C.; Cabral, L. C.; Farias,
C. A. A.; Domingues, A. M. Effect of enzymatic treatment and
filtration on sensory characteristics and physical stability of
soymilk. Food Control. 2003, 14, 187-192.
(
(14) King, J. M.; Min, D. B. Riboflavin-photosensitized singlet oxygen
oxidation product of vitamin D . J. Am. Oil Chem. Soc. 2002,
9, 983-987.
2
7
(
15) Grzelak, A.; Rychlik, B.; Bartosz, G. Light-dependent generation
of reactive oxygen species in cell culture media. Free Radical
Biol. Med. 2001, 30, 1418-1425.
16) Lucius, R.; Mentlein, R.; Sievers, J. Riboflavin-mediated axonal
degeneration of postnatal retinal ganglion cells in vitro is related
to the formation of free radicals. Free Radical Biol. Med. 1998,
(
2
4, 798-808.
(
17) Choe, E.; Huang, R.; Min, D. B. Chemical reactions and stability
of riboflavin in foods. J. Food Sci. 2005, 70, R28-R36.
18) Bradley, D. G.; Lee, H. O.; Min, D. B. Singlet oxygen detection
in skim milk by electron spin resonance spectroscopy. J. Food
Sci. 2003, 68, 491-494.
(19) Huang, R.; Kim, H. J.; Min, D. B. Photosensitizing effect of
riboflavin, lumiflavin, and lumichrome on the generation of
volatiles in soy milk. J. Agric. Food Chem. 2006, 54, 2359-
(
2
364.
LITERATURE CITED
(
20) Min, D. B.; Boff, J. M. Chemistry and reaction of singlet oxygen
(
1) Szczesniak, T.; Karabin, L.; Szczepankowska, M.; Wituch, K.
Biosynthesis of riboflavin by Ashbya gossypii. I. Influence of
fats of animal origin on riboflavin production. Acta Microbiol.
Pol., Ser. B 1971, 3, 29-34.
2) Gliszczynska, A.; Koziolowa, A. Flavins and Flavoproteins.
Proceedings of the 13th International Symposium; Konstanz,
Germany, Aug. 29-Sept. 4, 1999; pp 875-878.
in foods. Compr. ReV. Food Sci. Food Saf. 2002, 1, 58-72.
(21) Jung, M. Y.; Kim, S. K.; Kim, S. Y. Riboflavin-sensitized
photooxidation of ascorbic acid: kinetics and amino acid effect.
Food Chem. 1995, 53, 397-403.
(
(
22) Bradley, D. G.; Min, D. B. Singlet oxygen oxidation of foods.
Crit. ReV. Food Sci. Nutr. 1992, 31, 211-236.
(
23) Foote, C. S. Quenching of singlet oxygen. In Singlet Oxygen;
Wasserman, H., Murray, R. W., Eds.; Academy Press: New
York, 1979; pp 139-171.
(3) USDA National Nutrient Database for Standard Reference,
Release 16 Nutrient Lists, 2004.
(
4) Jung, M. Y.; Yoon, S. H.; Lee, H. O.; Min, D. B. Singlet oxygen
and ascorbic acid effects on dimethyl disulfide and off-flavor in
skim milk exposed to light. J. Food Sci. 1998, 408-412.
5) Allen, C.; Parks, O. W. Phtoodegradation of riboflavin in milks
exposed to fluorescent light. J. Dairy Sci. 1979, 62, 1377-1379.
6) Lee, K. H.; Jung, M. Y.; Kim, S. Y. Effects of ascorbic acid on
the light-induced riboflavin degradation and color changes in
milks. J. Agric. Food Chem. 1998, 46, 407-410.
(
24) Haag, W. R.; Mill, T. Rate constants for interaction of singlet
1
oxygen ( D
g
) with azide ion in water. Photochem. Photobiol.
1
987, 45, 317-321.
(
(
(
25) Huang, R.; Kim, H. J.; Min, D. B. Photosensitizing effect of
riboflavin, lumiflavin, and lumichrome on the generation of
volatiles in soy milk. J. Agric. Food Chem. 2006, 54, 2359-
2
364.
(
7) Huang, R.; Choe, E.; Min, D. B. Kinetics for singlet oxygen
formation by riboflavin photosensitization and the reaction
between riboflavin and singlet oxygen. J. Food Sci. 2005, 69,
C726-C732.
Received for review July 17, 2006. Revised manuscript received
November 7, 2006. Accepted November 12, 2006. This work was partly
supported by the Korea Research Foundation Grant to the Center for
Healthcare Technology Development, Chonbuk National University,
Jeonju, Korea.
(
8) Ahmad, I.; Fasihullah, Q.; Vaid, F. H. M. A study of simulta-
neous photolysis and photoaddition reactions of riboflavin in
aqueous solution. J. Photochem. Photobiol., B 2004, 75,
1
3-20.
JF061999Y