Tailored sample preparation for olive oil Analysis by 1 H-NMR: Applications in sensory evaluation, origin classification and polyphenol determination
Winkelmann, O., Kuechler, T., Tsimidou, M., Nenadis, N., Mastralexi, A., Bendini, A., Gonzalez, D. L. G., Gallina Toschi, T.
Abstract:
The 1H-NMR analysis of olive oil after dilution in CDCl3 has been exhaustively described in many scientific studies already. Due to the inherently low sensitivity of NMR, this approach provides little information about minor components present in the sample like polyphenols and volatiles.
An alternative sample preparation technique was developed and tested for its potential in addressing three important analytical issues. By employing a simple extraction with acetonitrile, a drastic enrichment of polyphenols and other polar compounds can be achieved. 1H-NMR analysis of these extracts can be used to classify olive oils according to geographical origin with striking success. In addition, markers attributable to the different sensory defects can be detected by the newly developed method, as demonstrated by the analysis of a large sample set of oils of different quality grades (extra virgin, virgin, lampante) which were assessed in parallel by sensory analysis. Affording extracts enriched in polyphenols, the method can also be used to determine the amount of polyphenols present in the oil. Employing the determination of phenolic content by the Folin Ciocalteu method, PLS-regression was used to predict the phenolic content from the NMR spectra. A high correlation between NMR data and the results from Folin Ciocalteu method was observed.
This work was developed in the context of the project OLEUM “Advanced solutions for assuring authenticity and quality of olive oil at global scale“ funded by the European Commission within the Horizon 2020 Programme (2014–2020, grant agreement no. 635690).
Download:
IMEKO-TC23-2017-080.pdf
DOI:
-
Event details
IMEKO TC:
TC23
Event name:
3rd IMEKOFOODS Conference
Title:

Metrology Promoting Standardization and Harmonization in Food and Nutrition

Place:
Thessaloniki, GREECE
Time:
01 October 2017 - 04 October 2017
 Back