Browsing by Author "Senol, Onur"

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Citation - WoS: 2
Citation - Scopus: 2
Combined Spectroscopic and Chromatographic Techniques Augmented With Chemometrics for the Authentication of Black Cumin ( Nigella Sativa L . ) Seed Oil
(Academic Press inc Elsevier Science, 2024) Celik, Saliha Esin; Ersoy, Seyda Karaman; Kaya, Elif Nilay; Senol, Onur; Apak, Resat
Edible oils adulteration has a great concern because of its health and economical effects. Black cumin seed oils (BCSOs) are one of the most adulterated edible oils. In this case, the purpose of this research was to investigate authenticity of commercial BCSOs by spectroscopic and chromatographic techniques combined with orthogonal partial least square -discriminant analysis (OPLS-DA) and hierarchical cluster analysis (HCA). Sixteen commercial BCSO samples (100 % pure-certified and other BCSOs), potential blending oils (sunflower, corn, and soybean oils), and twenty-one synthetically adulterated BCSO samples blended with sunflower (SFO), corn (CO), and soybean (SBO) oils at levels of 5 %, 10 %, 15 %, 20 %, 30 %, 40 %, and 50 % (v/v) were analysed. Screening of potential fingerprinting markers such as thymohydroquinone (THQ), thymoquinone (TQ), carvacrol (CRV), tocopherol isomers ( alpha-, gamma -, and delta -), as well as total antioxidant capacity and phenolic content analysis were carried out utilizing spectrophotometric CUPRAC, ABTS, and Folin Ciocalteu ' s assays. Commercial pure and fraudulent BCSOs and synthetically adulterated samples were successfully classified in OPLS-DA graphs with 95 % confidence level. Even to five percent detection limit for SFO, CO and SBO adulteration were prominently monitored. In consequence, the proposed spectroscopic and chromatographic methods seem to be a practically applicable, sensitive and versatile protocol that can be used as an alternative fingerprinting procedure to determine adulteration of commercial BCSOs.
Recognition of Clove (Eugenia Caryophyllata) Oil Adulteration by Monitoring Phenolic and Antioxidative Fingerprint Markers Utilizing Online HPLC Post Column and Spectrophotometric Assays With Chemometric Analysis
(Springer, 2025) Ersoy, Seyda Karaman; Kaya, Elif Nilay; Celik, Saliha Esin; Senol, Onur; Apak, Resat
This research aims to develop a reliable and versatile methodology for authenticating clove (Eugenia caryophyllata) oil (CLO). Key variables included total antioxidant capacity (TAC), total phenolic content (TPC), quantitative analyses and/or individual antioxidant capacity of fingerprint markers including eugenol (EUG) and tocopherol isomers (alpha-T, gamma-T, and delta-T) using reversed-phase liquid-chromatography (RP-HPLC) with post-column detection. A total of 28 commercial CLO samples (certified as 100% pure and other commercial samples), potential adulterants like vegetable oils (sunflower oil (SFO) and corn oil (CO)), and 14 synthetically adulterated CLO samples blended with varying proportions (ranging from 5 to 50%) of SFO and CO were analyzed. The EUG content and antioxidant capabilities of each marker were ascertained by online RP-HPLC analysis with post column detection utilizing CUPRAC (cupric reducing antioxidant capacity). EUG content in commercial CLO ranged from 1.46 to 98.06 mg g(-1), while TAC ranged between 18.54 and 748.46 mu mol g(-1) Trolox equivalents (TE), as determined by the online HPLC-CUPRAC method. Depending on the type and ratio of adulterating oils, a considerable decrease in the TAC values of virgin CLO was recorded. Classification of the commercial and synthetically adulterated CLOs (total of 42 samples) was performed using partial least square discrimination analysis (PLS-DA) and hierarchical cluster analysis (HCA). Adulteration levels above > 5% were successfully detected with 95% confidence. Thus, the proposed chemometric strategy combining selected chemical markers and TAC data demonstrated high potential for authenticating CLO. This technique provides a more focused investigation alternative for determining the authenticity and quality of commercial CLO.