XXVI Reunião Anual sobre Evolução, Sistemática e Ecologia Micromoleculares
Instituto de Química, Universidade Federal Fluminense, 1 a 3 de dezembro de 2004
XXVI RESEM
P12
Metabolomic Analysis of Juices of Brazilian Fruits by Nuclear
Magnetic Resonance.
Francisco Eduardo Aragão Catunda Júnior (PG) and Jan Schripsema (PQ).
Grupo Metabolômica, Laboratório de Ciências Quimicas, Centro de Ciência e Tecnologia,
Universidade Estadual do Norte Fluminense, Av. Alberto Lamego, 2000, 28015-620, Campos dos
Goytacazes, RJ, Brazil.
[email protected]
Introduction
1
Metabolomics is the newest of the
“omics”. Genomics profiles the genes and
gives
information
about
the
genetic
information which, in fact, is the same for
every cell of an organism. Transcriptomics
profiles the m-RNA and thus shows which
part of the DNA is being expressed at a
certain moment. Proteomics profiles the
proteins in organisms, tissues or cells. This
gives in principle information about the
metabolic processes which are active at a
certain moment. But the simple presence of
proteins does not give information about their
activity, which is among others determined by
co-factors, co-enzymes and availability of
substrates. To know something about their
activity the metabolites should be observed.
Metabolomics profiles the metabolites and, in
fact, the metabolites are the best indicators
for the actual state of an organism, tissue or
cell, because they are in general the effectors
of actions.
In the case of fruits the quality is mainly
determined by appearance, aroma and taste.
These features are determined by the
metabolites: E.g. appearance depends on
pigments; aroma on volatile substances; and
taste on sweet, bitter or acid compounds.
A metabolic profile of fruit could thus in a
simple way reflect the quality of the fruit.
In the present paper we investigated the
feasibility of Nuclear Magnetic Resonance
spectroscopy (NMR) for the metabolic
profiling of fruit juices.
Material and Methods
Fruit juices: Fruits were obtained from
normal commerce. The juices were obtained
by pressing the fruit. Samples were taken and
centrifuged. From the supernatant a 1.5 ml
sample was taken and lyophilized.
NMR spectroscopy: All spectra were
obtained on a JEOL Eclipse+ 400
spectrometer, operating at 400 MHz for
protons. The lyophilized material was
redissolved in deuterated water (D2O). The
1
H NMR spectrum was obtained with the
following parameters: pulse width 45o,
spectral width 10 ppm, spectral size 16K,
total acquisition time 2.7 s. Acquisition delay
4 s.
Identification of components: For the
identification of the components observable in
13
the fruit juices in some cases
C NMR
spectra were obtained or two-dimensional
NMR experiments were performed, e.g. 2DCOSY, HMQC or HMBC. These experiments
were executed using the standard Delta NMR
software package (version 3.2).
Discussion
NMR metabolic profiles were obtained for
more than 20 different fruit juices. All juices
could be clearly distinguished by differences
in the profiles. Generally the major
components of the fruit juices were sugars
(sucrose, glucose and fructose), but in certain
juices very high amounts of organic acids
XXVI Reunião Anual sobre Evolução, Sistemática e Ecologia Micromoleculares
Instituto de Química, Universidade Federal Fluminense, 1 a 3 de dezembro de 2004
were found, e.g. in lemon juice very high
amounts of citric acid were observed.
In many juices amino acids could be
observed. Secondary metabolites were only
observed in some rare cases.
Conclusions
It is possible to obtain characteristic
metabolic profiles of fruit juices by Nuclear
Magnetic Resonance Spectroscopy.
References
1
Fiehn, O.; Kopka, J.; Dörmann, P.; Altmann,
T.; Trethewey, R. N.; Willmitzer, L.; Nature
Biotechnol. 2000, 18, 1157.