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    Changes in volatile, key odorants and bioactive properties of pomegranate juice during processing into concentrate
    (Elsevier Sci Ltd, 2025) Salman, Eda; Guclu, Gamze; Pehlivan, Zeynep Yaren; Kelebek, Hasim; Selli, Serkan
    Key odorants of juices of pomegranate fruits of Hicaz variety obtained from different juice production stages (fresh: FrPJ, pasteurized: PPJ, filtered: FiPJ, and concentrated: CPJ) were examined. Processing significantly impacted the volatile compounds. The FrPJ and PPJ samples had higher concentrations of aroma compounds than the FiPJ and CPJ samples. A total of 38 aroma substances were identified in the FrPJ sample while 37, 35, and 21 compounds were detected in the PPJ, FiPJ, and CPJ samples, respectively. Phenylethyl alcohol was the dominant key odorant. The total phenolic contents (TPC) and antioxidant activities (AA) of the samples changed significantly. The CPJ sample had the highest TPC and AA due to increased release of phenolics during the concentration process; thus, this process increased the TPC and AA significantly, altering both aroma and bioactive properties. The results emphasize the importance of processing methods in preserving the nutritional and sensory qualities of pomegranate juice.
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    Characterization of the Key Odorants of Mastic Gum (Pistacia lentiscus var. Chia) from Two Different Countries
    (MDPI, 2025) Kilic-Buyukkurt, Ozlem; Guclu, Gamze; Kelebek, Hasim; Selli, Serkan
    Mastic gum, a plant-based resin from mastic trees, has become very popular in recent years and has been used in various food products due to its strong and positive aroma properties. In the present study, key odorant compounds of the mastic gum (MG) samples obtained from mastic gum trees (Pistacia lentiscus var. Chia) from two different countries, T & uuml;rkiye (MGT) and Greece (MGG), were investigated and compared. The aroma-active compounds (AACs) were determined by aroma extract dilution analysis (AEDA) and by using gas chromatography-mass spectrometry-olfactometry (GC-MS-O). The two mastic gum samples exhibited similar aroma profiles but significant differences were observed in their concentrations. Among the aroma groups identified in both samples, monoterpenes were the most abundant group with alpha-pinene as the main compound followed by beta-myrcene and beta-pinene. On the other hand, the most dominant AAC in both samples was determined to be alpha-pinene (resinous, forest-like odor), followed by beta-pinene (resinous, terpene-like odor), beta-myrcene (pine-like, greenish odor), and linalool (floral, fruity odor), all of which had high flavor dilution (FD) values. The findings of the AEDA and sensory analysis revealed that the MGT sample contained more floral and fruity odors while the MGG sample had more resinous and pine-woody odors.
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    Comparative elucidation of the phenolic profile and antioxidant and antimicrobial activities of unripe and ripe Pistacia lentiscus L. fruits and their oils as affected by ripening
    (Wiley, 2025) Buyukkurt, Ozlem Kilic; Guclu, Gamze; Kelebek, Hasim; Selli, Serkan
    BackgroundPhenolic compounds, antioxidant activity, and antimicrobial properties of unripe and ripe mastic tree (Pistacia lentiscus L.) fruits and their oils were investigated.ResultsA total of 20 phenolic compounds were identified by using liquid chromatography-diode array detection and electrospray ionization tandem mass spectrometry, among which phenolic acids were predominant. The main phenolic compound was catechin in the unripe fruit and trigalloylquinic acid in the unripe fruit oil, whereas galloylquinic acid was dominant in the ripe fruit and its oil. Unripe fruits had the highest amount of total phenolic content (TPC; 2771.4 mg kg-1), whereas the ripe fruit oils had the lowest TPC (14.1 mg kg-1). The quantity of the phenolics decreased as the fruits ripened. Tests revealed significant antimicrobial activity of the fruit extracts against Staphylococcus aureus but not on Escherichia coli, whereas fruit oils showed no antimicrobial effects.ConclusionThe fruits and their oils exhibited significant alterations in phenolic composition, antioxidant activity, and antimicrobial effects during ripening. These findings highlight the impact of ripeness on the bioactive properties of mastic tree fruits and their potential applications in the food and pharmaceutical industries. (c) 2025 Society of Chemical Industry.
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    Comparative Study of the Aroma Profiles and Bioactive Properties of Cooked and Uncooked Regular and Firik Bulgurs
    (Wiley, 2025) Kilic-Buyukkurt, Ozlem; Guclu, Gamze; Keskin, Muharrem; Kelebek, Hasim; Selli, Serkan
    Background and Objectives Bulgur is an important cereal product preferred due to its aroma, nutrition, and economic values. In this study, the effect of cooking process applied to two different bulgur types (regular and firik) on the aroma profile, color properties, total phenolic content (TPC), and antioxidant activity (AA) was evaluated. Findings A total of 27 and 33 aroma compounds were detected in the uncooked and cooked regular bulgur samples, while the firik bulgur samples (uncooked and cooked) had 27 and 34 compounds, respectively. Cooking process caused significant changes, with carboxylic acids and aldehydes being the dominant aroma groups. Uncooked firik bulgur exhibited the highest aroma concentration. Generally, both cooked (4225.6 ng/kg) and uncooked (4745.2 ng/kg) firik bulgurs had higher total aroma concentrations compared to the regular bulgurs (2333.0 and 3255.1 ng/kg). It was found that significant differences (p < 0.05) were observed in the TPC and AA levels; they were higher in firik bulgurs but decreased with the effect of cooking. Conclusion The study highlights that bulgur type and cooking process significantly affect its aroma and phenolic properties, potentially influencing consumer preferences. This is the first study to examine the aroma and bioactive compound variations in two bulgur types with respect to cooking.
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    Identification of key odorants in Turkish black tea beverage and aroma changes by adding aromatic plants
    (Academic Press Inc Elsevier Science, 2025) Gelen, Berfu; Guclu, Gamze; Kelebek, Hasim; Selli, Serkan
    Tea, produced from the leaves of Camellia sinensis, is one of the most widely consumed beverages worldwide. Some consumers infuse these teas by blending with different medicinal and aromatic plants for both taste and health benefits. This study examines the impact of adding four aromatic plants (dried cloves (C), mint (M), rose petals (R), and green tea (GT)) to black tea (BT) on its aroma profile, aroma-active compounds (AACs), and bioactive properties. Sensory analysis and gas chromatography-mass spectrometry (GC-MS) were used to evaluate the aroma profile, while total phenolic content (TPC) and antioxidant activity were measured to assess bioactive properties. The black tea (BT) sample with added green tea (BT+GT) had the highest total phenolic substance (TPC) and antioxidant activity (AA) followed by the BT+R, BT+C, BT+M and BT samples, respectively. The clove, mint, rose and green tea added to the BT increased its aroma potential significantly. The types and numbers of the AACs responsible for the unique odour of the tea samples showed significant differences. It was found that the characteristic aroma components found in the added aromatic plants were transferred to the BT. Sensory evaluation indicated that the aromatic plant additions enhanced the overall sensory characteristics of BT, with the BT+rose (BT+R) sample receiving the highest preference scores.
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    Machine Learning-Based Classification of Albanian Wines by Grape Variety, Using Phenolic Compound Dataset
    (MDPI, 2025) Topi, Ardiana; Kasaj, Agim; Hudhra, Daniel; Kelebek, Hasim; Guclu, Gamze; Selli, Serkan; Topi, Dritan
    Wine phenolics serve as robust chemical signatures correlated to grape variety, processing, and regional identity. This study explores the potential of machine learning algorithms, combined with the phenolic profiles of Albanian wines, to classify them according to grape variety. Geographic origin analysis was conducted as a preliminary exploration. The dataset of phenolic compounds included white and red wines, spanning the 2017 to 2021 vintages. Using five supervised algorithms-Support Vector Machine (SVM), Random Forest, XGBoost, Logistic Regression, and K-Nearest Neighbors-a high classification accuracy was achieved, with SVM reaching 100% under Leave-One-Out Cross-Validation (LOOCV). To address class imbalance, the Synthetic Minority Over-sampling Technique (SMOTE) and stratified cross-validation were applied. Random Forest feature importance consistently highlighted trans-Fertaric acid and Procyanidin B3 as dominant discriminants. Parallel coordinates plots demonstrated clear varietal patterns driven by phenolic differences, while PCA and hierarchical clustering confirmed unsupervised grouping consistent with wine type and maceration level. Permutation testing (1000 iterations) confirmed the non-randomness of model performance. These findings show that a small set of phenolic markers can offer high classification accuracy, supporting chemically based wine authentication. Although the dataset is relatively small, thorough cross-validation, non-redundant modeling, and chemical interpretability provide a solid foundation for scalable methods. Future work will expand the dataset and explore sensor-based phenolic measurement to enable rapid authentication in wine.
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    Phenolic Profiling of Merlot Wines from Albania: Influence of Geographical Origin and Vintage Assessed by LC-DAD-ESI-MS/MS
    (MDPI, 2025) Topi, Dritan; Kelebek, Hasim; Shehi, Gazmend; Guclu, Gamze; Selli, Serkan
    Merlot red wines rank among the most distinguished varietals globally. This study aimed to characterize the phenolic compound profiles of Merlot wines and assess the influence of geographical origin and vintage on samples from two Albanian wine regions. Using liquid chromatography coupled with tandem mass spectrometry, a total of 31 phenolic compounds were identified and quantified. These were classified into hydroxybenzoic acids and flavan-3-ols (13 compounds), phenolic acids (9), flavonols (5), and stilbenoids (4). The total phenolic content ranged from 294 mg L-1 in wines from the Mati-Mirdita region to 480 mg L-1 in those from the Durr & euml;s-Kavaja region, demonstrating significant regional variation. Notably, the hydroxybenzoic acids and flavan-3-ols exhibited the most pronounced differences, with gallic acid concentrations varying from 123 mg L-1 (Mati-Mirdita) to 170 mg L-1 (Durr & euml;s-Kavaja). Both regions' wines were rich in catechin, epicatechin, procyanidin derivatives, trans-caftaric acid, and ethyl gallate. However, procyanidins were found in higher concentrations in the Mati-Mirdita wines, while other phenolics were more abundant in Durr & euml;s-Kavaja samples. These findings underscore the influence of geographical and climatic factors on phenolic composition, offering a robust chemical fingerprinting approach for assessing wine authenticity and quality.
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    The cross breeding of Osmanli and Sabrina varieties to produce newly aroma-enriched strawberry genotypes
    (Academic Press Inc Elsevier Science, 2025) Saridas, Mehmet Ali; Guclu, Gamze; Selli, Serkan; Kelebek, Hasim; Kargi, Sevgi Paydas
    Strawberries are cultivated worldwide due to their unique flavor and important bioactive compounds. In this study, the aroma profiles of the 'Sabrina' and 'Osmanli' strawberry cultivars and eight selected hybrid genotypes derived from their cross were investigated using liquid-liquid extraction followed by gas chromatography-mass spectrometry (GC-MS). Both aroma and pomological characteristics were determined and compared among the parental cultivars (Osmanli and Sabrina) and selected genotypes. The total aroma content varied between 4650 mu g/kg in 'Sabrina' variety and 29272 mu g/kg in 'Osmanli' variety. The highest aroma quantity among the hybrids was determined in the genotype '2-10' (18769 mu g/kg). It was observed that the characteristic aroma of the 'Osmanli' variety was due to its high concentrations of esters compounds. As a result of the sensory analysis, the most liked genotype was determined as the genotype '2-10' which contained high amounts of esters. Additionally, unlike the Osmanli variety, this genotype has hermaphroditic flower structure, which is quite important in strawberry cultivation. It also had a 70 % increase in fruit size and a 50 % increase in fruit flesh firmness compared to the 'Osmanli'. This study shows that the breeding studies are crucial in strawberries to increase consumer satisfaction and market value; thus, the continuation of these studies is highly recommended.