title: Short wavelength Raman spectroscopy applied to the discrimination and characterization of three cultivars of extra virgin olive oils in different maturation stages.
abstract: Extra virgin olive oils produced from three cultivars on different maturation stages were characterized using Raman spectroscopy. Chemometric methods (principal component analysis, discriminant analysis, principal component regression and partial least squares regression) applied to Raman spectral data were utilized to evaluate and quantify the statistical differences between cultivars and their ripening process. The models for predicting the peroxide value and free acidity of olive oils showed good calibration and prediction values and presented high coefficients of determination (>0.933). Both the R(2), and the correlation equations between the measured chemical parameters, and the values predicted by each approach are presented; these comprehend both PCR and PLS, used to assess SNV normalized Raman data, as well as first and second derivative of the spectra. This study demonstrates that a combination of Raman spectroscopy with multivariate analysis methods can be useful to predict rapidly olive oil chemical characteristics during the maturation process.
authors.affiliation: CITAB - CITAB, University of Trás-os-Montes and Alto Douro, 5001-801 Vila Real, Portugal. Electronic address: igouvinhas@utad.pt.
authors.forename: Irene
authors.initials: I
authors.lastname: Gouvinhas
authors.affiliation: CITAB - CITAB, University of Trás-os-Montes and Alto Douro, 5001-801 Vila Real, Portugal.
authors.forename: Nelson
authors.initials: N
authors.lastname: Machado
authors.affiliation: Instituto Nacional de Investigação Agrária, (INIAI.P.), Elvas, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Carvalho
authors.affiliation: Department of Physics, University of Trás-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal; INESC-TEC, Rua do Campo Alegre, 687, 4169-007 Porto, Portugal.
authors.forename: José M M M
authors.initials: JM
authors.lastname: de Almeida
authors.affiliation: CITAB - CITAB, University of Trás-os-Montes and Alto Douro, 5001-801 Vila Real, Portugal.
authors.forename: Ana I R N A
authors.initials: AI
authors.lastname: Barros
mesh_terms: D002138:Calibration; D003627:Data Interpretation, Statistical; D016002:Discriminant Analysis; D006863:Hydrogen-Ion Concentration; D016018:Least-Squares Analysis; D015999:Multivariate Analysis; D031658:Olea / Q000737:chemistry* / Q000145:classification / Q000254:growth & development / Q000378:metabolism; D000069463:Olive Oil; D010545:Peroxides / Q000032:analysis / Q000378:metabolism; D010938:Plant Oils / Q000032:analysis*; D025341:Principal Component Analysis; D013045:Species Specificity; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D000069463:Olive Oil; D010545:Peroxides; D010938:Plant Oils
keywords: Acidity; Cultivars; Extra virgin olive oil; Maturation stages; Peroxide value; Raman spectroscopy