4th EucheMs chemistry congress

Poster Session 2
s1165
chem. Listy 106, s257–s1425 (2012)
Poster session 2 - food chemistry
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deterMininG 4-MethyLiMidAzoLe in CArAMeL
CoLor By CAPiLLAry GAS ChroMAtoGrAPhy
M. Lee 1 , K. hAn 1 , S. Choi 1 , S. h. KiM 2 , S. K. PArK 2 ,
h. S. LiM 2
1 Korea Health Industry Instititute, Qulity Improvement,
Chungju, Republic of Korea
2 Korea Food & Drug Administration, Food additive &
packaging, Osong, Republic of Korea
As a color additive, Caramel color is the world’s most
widely consumed food coloring ingredient. Caramel color
contains 2-methylimidazole and 4-methylimidazole, both of
which may cause cancer in laboratory animals. For such reason,
the 4-methylimidazole content of caramel color, a food additive,
is controlled in the EU, US(FCC), Japan, and Korea.
The quantitative analysis of the 4-methylimidazole used in
Korea’s Food Additive Code and US’s FCC (Food Chemical
Codex) is a somewhat old-fashioned gas chromatography using
column packing of 7.5% Carbowax 20M +2% KOH.
For the aforesaid reason, a method of determining
4-methylimidazole in caramel color via capillary gas
chromatography was studied. The method consisted of methylene
chloride extraction of the sample followed by concentration and
GC analysis.
GC analysis was performed using HP-20M, Carbox 20M,
HP-5 capillary column (0.32?, ID?25M), and hydrogen
flame-ionization detector. As internal standard material,
2-methylimidazole was used.
The linear range was 0.08~1.6?/L, and the limit of detection
was 0.04 ?/L. The average recoveries were 90.4~98.0%, and the
relative standard deviations were 0.8 ~2.5%. Consequently,
4-methylimidazole contained in caramel color was analyzed using
the capillary column, which is currently used widely.
Keywords: 4-methylimidazole; Caramel; Gas
Chromatography; Capillary;
4 th EucheMs chemistry congress
P - 0 6 0 7
direCt MonitorinG of MyoGLoBin-CAtALyzed
LinoLeAte PeroxidAtion By fourier
trAnSforM infrAred SPeCtroSCoPy
A. LouLLiS 1 , e. PinAKouLAKi 1
1 University of Cyprus, Department of Chemistry, Nicosia,
Cyprus
Lipid peroxidation reactions are a major concern in Food
Science. These reactions represent a main part of the degrading
processes taking place in food products resulting in changes in
flavor, color, texture and producing cytotoxic and genotoxic
compounds. Myoglobin has been demonstrated to catalyze lipid
peroxidation in biological tissues and muscle-based foods. In this
work we have employed UV/Vis and Fourier transform infrared
spectroscopies to study the mechanism of myoglobin-catalyzed
linoleate per oxidation. The UV/Vis spectra of the reaction of
linoleate with met-myoglobin and with ferry-myoglobin show
characteristic transitions at 235 nm and 285 nm indicating the
formation of primary and secondary oxidation products.
Ferryl-myoglobin is potent in inducing linoleate peroxidation
independent of the linoleate/Mb ratio, while met-myoglobin has
been found to be an effective catalyst only in high ratios (1:300).
We have also monitored the reactions using Fourier Transform
Infrared spectroscopy. During the reactions the decreasing
intensity of marker linoleate vibrations and appearance of new
vibrations in the 1700–1600 cm-1 and 1500–900 cm-1 regions that
can be attributed to linoleate primary and secondary oxidation
products have allowed us to directly monitor the process of
linoleate peroxidation. Concurrent changes in the secondary
structure of myoglobin are observed through amide I and amide
II modes. The antioxidant activity of vitamin C has been
investigated and will be discussed.
Keywords: Oxidation; Proteins; Lipids; IR spectroscopy;
UV/Vis spectroscopy;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc