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    A comparison of the volatile and phenolic compositions of Muscat of Bornova wines from two different terroirs in the Aegean region of Turkey
    (Soc Brasileira Ciencia Tecnologia Alimentos, 2020) Yabaci Karaoglan, Selin; Cabaroglu, Turgut
    This study investigated the aromatic and phenolic compositions of two different Muscat of Bornova wines from two distinct terroirs (Izmir and Manisa) and compared them to basic terroir properties over the course of two consecutive years. The 53 volatile and 14 phenolic compounds found, were identified and quantified by GC-MS-FID and HPLC-DAD with MS, respectively. The Menderes terroir has higher amounts of terpene and C6 compounds which are varietal aroma compounds. The total phenolic content in the Menderes terroir is higher than in the Kemaliye terroir. Trans-caftaric acid was the most abundant phenolic compound According to the statistical results, most of the compounds were affected by both vintage and terroir; however, the effect of vintage seems to be more significant.
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    Maltose-Negative Yeast in Non-Alcoholic and Low-Alcoholic Beer Production
    (MDPI, 2022) Yabaci Karaoglan, Selin; Jung, Rudolf; Gauthier, Matthew; Kin?l, Tomáš; Dostálek, Pavel
    Although beer is a widely used beverage in many cultures, there is a need for a new drink-ing alternative in the face of rising issues such as health concerns or weight problems. However, non-alcoholic and low-alcoholic beers (NABLAB) still have some sensory problems that have not been fully remedied today, such as “wort-like”/”potato-like” flavours or a lack of aroma. These defects are due to the lack of alcohol (and the lack of the aldehyde-reducing effect of alcohol fermen-tation), as well as production techniques. The use of new yeast strains that cannot ferment maltose— the foremost sugar in the wort—is highly promising to produce a more palatable and sustainable NABLAB product because production with these yeast strains can be performed with standard brewery equipment. In the scientific literature, it is clear that interest in the production of NABLAB has increased recently, and experiments have been carried out with maltose-negative yeast strains isolated from many different environments. This study describes maltose-negative yeasts and their aromatic potential for the production of NABLAB by comprehensively examining recent academic studies. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
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    Maturation-Dependent Changes in Volatile Aroma Profile and ?-Glucosidase Activity in Kozan Misket Orange (Citrus sinensis L.)
    (MDPI, 2025) Yabaci Karaoglan, Selin
    Background/Objectives: Kozan Misket orange (Citrus sinensis L.) is a regional Turkish cultivar valued for its unique flavor, yet the mechanisms underlying its aroma development remain unclear. Volatile compounds are key contributors to citrus sensory quality, and beta-glucosidase is involved in releasing glycosidically bound aroma precursors. However, no previous study has examined the interaction between enzyme activity and volatile production during maturation in this cultivar. This study aimed to characterize the dynamic changes in volatile composition and beta-glucosidase activity across different maturation stages of Kozan Misket orange. Methods: Fruits were harvested at three maturity stages (green, green-yellow, yellow). Physicochemical traits (TSS, TA, TSS/TA), volatile profiles (HS-SPME/GC-MS), and specific beta-glucosidase activity were analyzed. Volatile compounds were identified, quantified, and compared across stages. Results: A total of 47 volatile compounds were identified, with monoterpenes dominating at all stages. D-limonene was the most abundant compound, exceeding 86% of total volatiles. Total volatile content increased with maturation, particularly monoterpenes and sesquiterpenes, whereas oxygenated monoterpenes (e.g., linalool, 4-terpineol, alpha-terpineol) declined at full maturity. Specific beta-glucosidase activity decreased markedly from 20.15 to 8.25 U mg-1 protein. This shift suggests that bound precursors contribute more to early-stage aroma release, while later-stage aroma accumulation may rely on metabolic conversions. Conclusions: This study provides the first integrated insight into aroma development in Kozan Misket orange, revealing a dual-phase mechanism linking volatile formation and beta-glucosidase activity. These findings clarify cultivar-specific flavor development and offer guidance for harvest optimization and flavor management.
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    The general and volatile properties and the quality of two newly selected Satsuma clones (11/1 Izmir and 30/Izmir) grown under Mediterranean ecological conditions
    (Soc Brasileira Ciencia Tecnologia Alimentos, 2019) Ozkaya, Okan; Yabaci Karaoglan, Selin; Incesu, Meral; Yesiloglu, Turgut
    The general and volatile properties, and the quality of two new Satsuma clones - 11/1 Izmir and 30/Izmir - selected under a Citrus Bud Wood Selection Program, were compared with Owari Satsuma samples grown under Adana ecological conditions. Gas chromatography, mass spectrometry, flame ionization detection (GC/MS/FID) analysis was used in the identification and quantification of the aromatic compounds, and a sensory profile analysis was performed to complete the general understanding using chemical analysis. The general analysis showed that the clone samples have higher yields, are more intense in skin color and more acidic; however, the total soluble solids and total sugar amount are lower than the Owari Satsuma samples. The terpenes are the major aromatic compound class. Along with other terpenes, there were significant amounts of dl-limonene followed by gamma-terpinene, beta-elemene, linalool and alpha-terpineol. The sensory analysis showed that the Owari Satsuma samples are sweeter and riper, with a better floral, spicy-citrus flavor than both clones. Both clones had a lower Overall liking rating than the Owari Satsuma samples.