Similarity calculations and differential NMR in the search of marker compounds for food identity and quality

Similarity Calculations and Differential NMR in the Search of MarkerCompounds for Food Identity and Quality

 

*Jan Schripsema1, Leonardo Dagnino Schripsema2, Junio Rangel Botelho1, Ronald dos Santos Merlim1, Denise Dagnino3

1 Grupo Metabolômica, Laboratório de Ciências Quimicas, Universidade Estadual do Norte

Fluminense, Campos dos Goytacazes, RJ, Brazil

2Instituto de Computação, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil

3 Grupo Metabolômica, Laboratório de Biotecnologia, Universidade Estadual do Norte

Fluminense, Campos dos Goytacazes, RJ, Brazil

*jan@uenf.br

 

In metabolomics and foodomics studies one generally looks for marker compounds. In these studies

NMR is one of the most used techniques and a certain standard procedure can be recognized. This

involves the following steps: binning of the NMR spectra and comparison of the data with

multivariate data analysis, such as Principle Component Analysis (PCA). This procedure is however

not suitable to detect low abundant marker compounds. This led to the development of an

alternative methodology involving similarity calculations and subsequent differential NMR1

. Thesuccess of this methodology was confirmed in subsequent studies, e.g. with essential oils and

drugs2,3

.For the implementation of the new methodology a software tool was developed with the name

SIMBA (SIMilarity Based Alignment). This tool provides an accurate alignment of the different

NMR spectra of an experiment based on similarity calculations. When the peaks of the spectrum are

well aligned the highest similarity is obtained. It was already shown in previous studies that the

calculated similarities are very useful for sample classification and provide similar results as PCA

analysis. The SIMBA program exports a similarity table of all the spectra and a spreadsheet with all

the aligned spectra, which can then be used for differential NMR.

In the presentation recent results are shown on the analysis and characterization of different food

products, such as cheese, tea and essential oils. By differential NMR different types of cheeses are

easily characterized. Also for the determination of the origin of the milk it was found to be useful,

e.g. to distinguish cheese from cow or sheep.

Different types of tea are easily distinguished and also the caffeine contents are readily determined.

For the analysis of essential oils especially 13C NMR was found to be very useful and minor

compounds can be analysed down to similar levels as those obtained with GC-MS.

Acknowledgments: CNPq, CAPES and FAPERJ for financial support.

 

References

1. J. Schripsema. Metabolomics, 15, 39 (2019).

2. J. Schripsema, et al. Talanta, 237, 122928 (2022).

3. J. Schripsema, et al. J. Pharm. Biomed. Anal., 215, 114773 (2022).