Evaluation of extra-virgin olive oils shelf life using an electronic tongue—chemometric approach
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Physicochemical quality parameters, olfactory and gustatory–retronasal positive sensations of extra-virgin olive oils vary during storage leading to a decrease in the overall quality. Olive oil quality decline may prevent the compliance of olive oil quality with labeling and significantly reduce shelf life, resulting in important economic losses and negatively condition the consumer confidence. The feasibility of applying an electronic tongue to assess olive oils’ usual commercial light storage conditions and storage time was evaluated and compared with the discrimination potential of physicochemical or positive olfactory/gustatory sensorial parameters. Linear discriminant models, based on subsets of 5–8 electronic tongue sensor signals, selected by the meta-heuristic simulated annealing variable selection algorithm, allowed the correct classification of olive oils according to the light exposition conditions and/or storage time (sensitivities and specificities for leave-one-out cross-validation: 82–96 %). The predictive performance of the E-tongue approach was further evaluated using an external independent dataset selected using the Kennard–Stone algorithm and, in general, better classification rates (sensitivities and specificities for external dataset: 67–100 %) were obtained compared to those achieved using physicochemical or sensorial data. So, the work carried out is a proof-of-principle that the proposed electrochemical device could be a practical and versatile tool for, in a single and fast electrochemical assay, successfully discriminate olive oils with different storage times and/or exposed to different light conditions.
KeywordsExtra-virgin olive oil Sensory attributes intensity perception Electronic tongue Linear discriminant analysis Simulated annealing algorithm
The authors acknowledge the financial support from the strategic funding of UID/BIO/04469/2013 unit, from Project POCI-01-0145-FEDER-006984—Associate Laboratory LSRE-LCM funded by FEDER funds through COMPETE2020—Programa Operacional Competitividade e Internacionalização (POCI)—and by national funds through FCT—Fundação para a Ciência e a Tecnologia and under the strategic funding of UID/BIO/04469/2013 unit. Nuno Rodrigues thanks FCT, POPH-QREN and FSE for the Ph.D. Grant (SFRH/BD/104038/2014).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Compliance with ethics requirements
This article does not contain any studies with human participants or animals performed by any of the authors.
- 2.Ben-Hassine K, Taamalli A, Ferchichi S, Mlaouah A, Benincasa C, Romano E, Flamini G, Lazzez A, Grati-kamoun N, Perri E, Malouche D, Hammami M (2013) Physicochemical and sensory characteristics of virgin olive oils in relation to cultivar, extraction system and storage conditions. Food Res Int 54:1915–1925CrossRefGoogle Scholar
- 4.Ayyad Z, Valli E, Bendini A, Adrover-Obrador S, Femenia A, Toschi TG (2015) Extra-virgin olive oil stored in different conditions: focus on diglycerides. Ital J Food Sci 27:166–172Google Scholar
- 7.Mendez AI, Falque A (2007) Effect of storage time and container type on the quality of extra-virgin olive oil. Food Chem 18:521–529Google Scholar
- 11.Sinesio F, Moneta E, Eaffo A, Lucchetti S, Peparaio M, D’Aloise A, Pastore G (2015) Effect of extraction conditions and storage time on the sensory profile of monovarietal extra virgin olive oil (cv Carboncella) and chemical drivers of sensory changes. LWT-Food Sci Technol 63:281–288CrossRefGoogle Scholar
- 16.Garrido-Delgado R, Dobao-Prieto MM, Arce L, Aguilar J, Cumplido JL, Valcárcel M (2015) Ion mobility spectrometry versus classical physico-chemical analysis for assessing the shelf life of extra virgin olive oil according to container type and storage conditions. J Agric Food Chem 63:2179–2188CrossRefGoogle Scholar
- 31.Rodríguez-Méndez ML, Apetrei C, de Saja JA (2010) Chapter 57—electronic tongues purposely designed for the organoleptic characterization of olive oils olives. In: Preedy V, Watson RR (eds) Olives and olive oil health and disease prevention. Academic Press, Elsevier Inc, Oxford, pp 525–532CrossRefGoogle Scholar
- 34.Afaneh IA, Abbadi J, Ayyad Z, Sultan W, Kanan K (2013) Evaluation of selected quality degradation indices for Palestinian extra virgin olive oil bottled in different packaging materials upon storage under different lighting conditions. J Food Sci Eng 3:267–283Google Scholar
- 35.Rababah TM, Feng H, Yang W, Eriefej K, Al-Omoush M (2011) Effects of type of packaging material on physicochemical and sensory properties of olive oil. Int J Agric Biol Eng 20:66–72Google Scholar
- 36.Anonymous (1991) Commission regulation (ECC) nº 2568/91: on the characteristics of olive oil and olive-pomace oil and on the relevant methods of analysis. Off J Eur Union L248:1–82Google Scholar
- 37.International Olive Council (2013) Sensory analysis of olive oil—method for the organoleptic assessment of virgin olive oil. COI/T.20/Doc. No. 15/Rev. 6 November 2013, 18 pp. http://www.internationaloliveoil.org/
- 38.International Olive Council (2014) IOC Mario Solinas quality award—rules of the international competition for extra virgin olive oils. T.30/Doc. No. 17 June 2014, 9 pp. http://www.internationaloliveoil.org/
- 42.Miller J, Miller JC (2010) Statistics and chemometrics for analytical chemistry, 6th edn. Prentice Hall, Harlow, pp 231–235Google Scholar
- 50.Dabbou S, Gharbi I, Dabbou S, Brahmi F, Nakbi A, Hammami M (2011) Impact of packaging material and storage time on olive oil quality. Afr J Biotechnol 10:16937–16947Google Scholar