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    Safe and Fast Fingerprint Aroma Detection in Adulterated Extra Virgin Olive Oil Using Gas Chromatography-Olfactometry-Mass Spectrometry Combined with Chemometrics
    (Springer, 2021) Drira, Malika; Güçlü, Gamze; Portoles, Tania; Jabeur, Hazem; Kelebek, Haşim; Selli, Serkan; Bouaziz, Mohamed
    The undeclared blending of extra virgin olive oils (EVOOs) with refined pomace olive oils (RPOO) is a well-known fraudulent practice. Despite the efforts made, it still remains a highly challenging authenticity issue to deal with. The present paper presents a fast fingerprint aroma technique, namely gas chromatography-olfactometry-mass spectrometry, which were tested as rapid screening tools for the detection of this adulteration.To overcome the lack of real adulterated samples was used to prepare EVOO mixtures with RPOO at different percentages. Besides, the quality indices was used as good markers to detect the illicit blends from the authentic oils such as K-232 with 4% RPOO, K-270 with 3% RPOO, and the variation of specific extinction (Delta K) of the adulterated EVOO with 10% RPOO. The addition of > 20% RPOO to EVOO would not be detected by the amount of TC18:1, fatty acids, and peroxide value. Moreover, using the sum of octadecadienoic and octadecatrienoic TFA isomers (TC18:2 + TC18:3) was confirmed to be good purity indices for the adulteration with 10 and 20% of RPOO. However, the main triglyceride found in oils samples were SOL + POO, OOL + LnPP, and OOO + PoPP as expected from the high oleic acid and low contents in linoleic and linoleic acid. Regarding volatile composition, thirty-four relevant aroma compounds and twenty-one key odorants were quantified in EVOO, RPOO, and EVOO adulterated with 1-20% of RPOO.
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    Targeted analysis for detection the adulteration in extra virgin olive oil's using LC-DAD/ESI-MS/MS and combined with chemometrics tools
    (Springer, 2020) Drira, Malika; Kelebek, Haşim; Güçlü, Gamze; Jabeur, Hazem; Selli, Serkan; Bouaziz, Mohamed
    The hand-held LC-DAD/ESI-MS/MS approach was employed, for the first time, for the quantification of extra virgin olive oil (EVOO) adulteration with refined pomace olive oil (RPOO). The total polyphenols (TP) and sterols were quantified according to their chemical methods, with more reliable methods required in this field to avoid undue dependence on chlorophylls, carotenoids contents and antioxidant activity (DPPH assays), which were evaluated by spectrophotometric methods. Some differences concerning the antioxidant activity and the TP content were observed. Actually, Chemlali EVOO activity was the most pronounced (13.84 +/- 0.21%) and it contained the highest TP content (284.54 +/- 4.27 mg/kg). Indeed, a correlation between antioxidant activity, TP and oxidative stability was established herewith. The metabolomics data were elaborated with the help of chemometric tools i.e. principal component analysis (PCA) and hierarchical cluster analysis (HCA). This approach allowed the estimation of the best discrimination markers for EVOO authenticity evaluation (i.e. Hydroxytyrosol quinone, oxidized hydroxytyrosol, 3,4-DHPEA-EA, p-HPEA (tyrosol), p-coumaric acid, luteolin, decarboxymethyl 10-hydroxyoleuropein aglycon, beta-sitosterol apparently; campesterol, stigmasterol, increment Delta-7-stigmastenol and increment Delta-7-avenasterol). [GRAPHICS] .