"Metabolomics" is the science dedicated to study the profiles and metabolic patterns of a living organism, the so-called "metabolome". The metabolome serves as a monitor of the genetic expression (phenotype) or to understand certain characteristics of the organism [1] giving an image of its overall biochemical situation. A typical metabolomic study needs data from biology, natural products chemistry and analytical chemistry that must be statistically significant to properly correlate these observations. It is a simultaneous multi-component analysis of thousands of compounds contained in one single fraction (or extract) of the organism, that gives the “fingerprint” of its metabolome. The thoroughly analysis of it, triggers the discovery of specific markers of a special property or condition of the organism being studied. There are two types of metabolomic studies: the targeted and the untargeted. While the first one focuses on a reduced number of known metabolites with reported biological activity, the other one is the best way to detect changes within the whole metabolic profile, as all the metabolome is analyzed in one single analysis using powerful spectroscopical methods such as ToF-MS or NMR.

An untargeted metabolomics approach was applied aiming to correlate flavor and consumers’ acceptance of 8 varieties of mandarins to their metabolic profile. We followed Choi’s broad polarity extraction method [2] to cover the widest portion of the metabolome. The extracts were analyzed through 1H NMR (400 MHz). The acquired spectra were processed, aligned and binned to allow the comparison between samples. Finally, we used statistic metabolomic tools to correlate the spectral data with consumers’ acceptance results in order to identify the signals that weighted the most in the differentiation between samples [3].

The results show that this type of analytical approach, initially thought for disease identification in human samples [4], is also useful in natural products analysis and their correlation with different types of bioactivity, in this case taste and flavor, from which objective tools for their evaluation are not usually described. These results could be useful in genetic development programs to select new cultivars based in chemical data that match on consumers’ acceptability without bias or subjective opinions, speeding up the development of new commercially available varieties.

[1] Verpoorte, R., Choi, Y. H., Kim, H. K., NMR-based metabolomics at work in phytochemistry. Phytochemistry Reviews, 2007. 6: p. 3-14.
[2] Choi, H.K., Yoon, J. H., Kim, Y. S., Kwon, D. Y., Metabolomic profiling of Cheonggukjang during fermentation by 1H NMR spectrometry and principal components analysis. Process Biochemistry 2007. 42: p. 263-266.
[3]Cox, D.G., et al., The utility of metabolomics in natural product and biomarker characterization. Biochimica et Biophysica Acta (BBA) - General Subjects. 1840(12): p. 3460-3474.
[4] Ngana Gowda, G.A. et al. Metabolomics-Based Methods for Early Disease Diagnostics: A Review. Expert Rev Mol Diagn. 2008 Sep: 8(5): p. 617–633.