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Percorrer por autor "Ruano, Daniela"

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  • FTIR coupled with chemometrics as a non-invasive tool for PDO olive oils’ discrimination
    Publication . Lamas, Sandra; Ruano, Daniela; Rodrigues, Nuno; Barreiro, Filomena; Peres, António M.; Pereira, José Alberto
    Quality schemes protect the diversity of traditional European foods, such as the Protected Designation of Origin (PDO) and the Protected Geographical Indication (PGI). Only the olive oils from extra virgin and virgin commercial categories can be labelled with a PDO or PGI. In Portugal, currently, there are six PDOs. Olive oils labelled as PDO present a superior chemical-sensory quality. Nevertheless, from a commercial point of view it is of paramount importance to be able to identify them according to the correct label, avoiding fraud and ensuring the consumer regarding the exact origin of the purchased oil. Non-invasive and fast techniques, like Fourier transform infrared spectroscopy (FTIR), have been applied to assess olive oil origin and to detect fraud and adulterations. Thus, this work aimed to use FTIR spectra coupled with linear discriminant analysis-simulated annealing algorithm (LDA-SA) to classify commercial olive oils belonging to three Portuguese PDOs, namely, ‘Alentejo Interior’, ‘Beira Interior’, and ‘Trás-os-Montes’. The results showed that a FTIR-LDA-SA model could classify 30 independent oils according to the correct PDO with a sensitivity and specificity of 100% (training, leave-one-out cross-validation) and a sensitivity of 97.5% for the repeated K-fold cross-validation), based on the transmittance values recorded at six selected wavenumbers.
    2023Comunicação em conferência Acesso aberto Ver mais
  • Influence of geographical origin on the sensory and volatile profiles of Portuguese monovarietal olive oils
    Publication . Rocha, Pedrina; Ruano, Daniela; Ferreiro, Nuno; Martins, Luísa L.; Rodrigues, Nuno
    The sensory and volatile profiles of monovarietal olive oils from the Portuguese cultivars Cobrançosa and Galega, produced in three geographical regions (Alentejo, Beira Interior, and Trás-os-Montes), were investigated to evaluate the effects of cultivar and geographical origin. All samples were classified as extra virgin olive oil. Sensory analysis revealed significant differences (p < 0.05) between cultivars and among regions. Cobrançosa olive oils exhibited an intense green sensory profile, characterized by high green fruitiness, and tomato, apple, and herbaceous notes, particularly in oils from Trás-os-Montes and Alentejo. In contrast, Galega olive oils showed a more balanced and moderated sensory profile, with lower intensities of bitterness and pungency and variability among regions. Volatile characterization by HS–SPME–GC–MS led to the identification of 26 compounds in Cobrançosa and 29 in Galega olive oils, grouped into seven chemical families. Olive oils from Beira Interior and Trás-os-Montes showed higher concentrations of lipoxygenase-derived C5 and C6 compounds, such as (E)-2-hexenal, associated with green and fruity sensory sensations, whereas Alentejo oils exhibited lower volatile diversity but higher relative abundance of certain sesquiterpenes. Pearson correlation analysis revealed a strong association between sensory descriptors and key volatile compounds, highlighting region specific sensory-chemical patterns. Linear discriminant analysis (LDA) based on sensory and volatile data achieved excellent classification performance, with accuracies up to 100% for both cultivars. Overall, the results demonstrate an interaction between cultivar and geographical origin, supporting the use of sensory and volatile profiling as tools for the differentiation and authentication of Portuguese monovarietal olive oils.
    2026Artigo científico Acesso aberto Ver mais