Browsing by Author "Kaya, Ozkan"

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Anom Approach for the Statistical Evaluation of Organic Acid Contents of Clones of the Grape Variety 'kalecik Karasi
(Hohere Bundeslehranstalt & Bundesamt Wein-& Obstbau Klosterneuburg, 2021) Keskin, Nurhan; Kunter, Birhan; Celik, Hasan; Kaya, Ozkan; Keskin, Siddik
Organic acids have an important effect on flavor, aroma and color in berries and wines of grapes and they also play an important role for the microbiological and biochemical stability of the wine. The variety 'Kalecik Karasi' is one of the exclusive red grape varieties of Turkey. The aim of this study is to evaluate and visualize the differences between the 23 clones of 'Kalecik Karasi' with respect to organic acids. As organic acids were considered: tartaric, malic, citric, succinic and fumaric acids. The berries of the vintages 2016 and 2017 were harvested with 23 % soluble solids and HPLC (High Performance Liquid Chromatography) was used to identify organic acid content. Using Analysis of Means (ANOM) method the mean of each group was compared to the overall or grand mean to identify statistically significant differences. Thus the differences between the 'Kalecik Karasi' clones in terms of organic acids were compared and visualized by this method. According to the results, for all organic acids, except for tartaric and fumaric acid, differences between means of clones and overall mean are statistically significant (p<0.05). Both ANOVA and ANOM can be appropriate for determining differences between the groups. However, ANOM provides a simple graphical representation for group means. Therefore, it can be concluded that this method can be suggested to visualize differences between the groups for easy interpretation.
Antioxidant Activity and Biochemical Compounds of Vitis Vinifera L. (Cv. 'katikara and Vitis Labrusca L. (Cv. 'isabella Grown in Black Sea Coast of Turkey
(Springer, 2021) Keskin, Nurhan; Ekbic, Hatice Bilir; Kaya, Ozkan; Keskin, Siddik
The antioxidant activity and phenolic compounds content of pomace from the berries of 'Isabella' and 'Katikara' grape varieties widely produced in the Eastern Black Sea region of Turkey were researched for use as a potential natural antioxidant source. The results of this study indicated that there were statistically significant differences (p < 0.05) between two varieties for some biochemical compounds. There are high positive correlations among antioxidant activity, phenolic compounds and 'Isabella'. Similarly, catechin, citric acid, epicatechin, tartaric acid, total phenolic, vitamin C, gallic acid and p-coumaric acid are strongly and positively correlated with each other. It was observed that 'Isabella' grapes presented higher antioxidant potential with relating presence of high content of phenolic compounds. Mineral elements, which are of great importance for cell protection and healthy teeth, bone and skin structure, were found widely in the 'Katikara' variety. As a result, we can concluded that consuming these two grape varieties will provide significant benefits in blood pressure, heart rhythm, muscle functions, protection of fluid balance in the body, reproduction and many other functions in the human body.
Biogenic Amines in Raisins of One Vintage Year: Influence of Two Chemical Pre-Treatments (Dipping in Oak Ash Solution or Potassium Carbonate Solution)
(Hohere Bundeslehranstalt & Bundesamt Wein-& Obstbau Klosterneuburg, 2022) Ates, Fadime; Kaya, Ozkan; Keskin, Nurhan; Turan, Metin
Some biogenic amines (BAs) may be used as quality markers in grape derived products and they have key roles in human nutrition. In this study, therefore, two traditional dipping solutions, namely oak ash and potassium carbonate solutions applied before drying, were compared for their effects on the BA profile of Gok Uzum raisins. The mean agmatine, putrescine, spermine, and serotonin content of Gok Uzum raisins was lower in samples dried by dipping in potassium carbonate solution than samples dried by dipping in oak ash solution. There were no significant differences in contents of cadaverine, spermidine, histamine, tryptamine, dopamine, and norepinephrine between samples of both dipping solutions. Among the BAs under investigation, putrescine, agmatine, histamine, and tryptamine were the most abundant amines, whereas the lowest amine contents were those of cadaverine, spermine, spermidine, and norepinephrine. The mean putrescine, agmatine, spermine, and serotonin content of Gok Uzum raisins was higher in samples dried by dipping in oak ash solution than in samples dried by dipping in potassium carbonate solution. Drying under shade by dipping in oak ash solution proved to be superior to dipping in potassium carbonate solution concerning Gok Uzum raisin BAs and could be considered as an attractive pre-drying solution for the production of both raisins and perhaps other dried fruits.
Comparison of Contents of Sugars, Organic Acids and Free Amino Acids in Raisins Obtained From Gok Uzum (Vitis Vinifera L.)
(Hohere Bundeslehranstalt & Bundesamt Wein-& Obstbau Klosterneuburg, 2023) Karakus, Sinem; Ates, Fadime; Keskin, Nurhan; Turan, Metin; Kaya, Ozkan
Raisins are known as an important source of many bioactive compounds such as organic acids, free amino acids, and sugars. In this study, oak ash and potassium carbonate solutions applied before drying were compared for their effects on the Gok Uzum raisin, more specifically, its contents of organic acids, free amino acids, and sugar profile. The total acidity quantified in the samples of raisin, ranged from 20.30 to 117.08 ng/mu L DW for the potassium dipping solution, while values ranged from 17.98 to 164.72 ng/mu L DW for the oak ash dipping solution. In samples from either dip solution, serine was predominant, followed by alanine, asparagine, glutamine, aspartate, sarcosine, glutamate, and leucine, whereas glycine, arginine, proline, histidine, and valine were found to be the lowest amino acids. In the samples examined, fructose was the most abundant sugar, whereas the lowest sugars in raisins were xylose for oak ash application and galactose for potassium carbonate application. There was wide variation in the sugar profiles for both variants, with values ranging from 3043.48 to 0.71 g/100 g DW. Drying Gok Uzum grapes after the treatment of oak ash dipping solution promotes a higher content of organic acids, amino acids and sugars as compared to drying after potassium carbonate solution treatments. These results could be used for the development of an attractive pre-drying solution in further studies for the production of both, raisins and perhaps other dried fruits.
Comparison of the Sugar and Organic Acid Components of Seventeen Table Grape Varieties Produced in Ankara (Türkiye): a Study Over Two Consecutive Seasons
(Frontiers Media Sa, 2024) Kunter, Birhan; Unal, Osman Batur; Keskin, Siddik; Hatterman-Valenti, Harlene; Kaya, Ozkan
Sugars and organic acids not only have a significant impact on taste balance and sensory acceptance by consumers but also play a crucial role in the chemical equilibrium of grape juices and wines. Therefore, this study aimed to quantify the content and composition of sugars and organic acids in 17 grape varieties over two consecutive years using high-performance liquid chromatography. The variability in all the parameters studied was strongly influenced by both the grape cultivars and specific years (p <= 0.05). In grape berries, the primary sugars identified were fructose and glucose, which ranged from 6.50 to 11.10 g/L and from 5.83 to 12.12 g/L, respectively, over the two years. However, sucrose was not detected in any of the grape varieties examined. For the two respective years, the highest titratable acidity (TA) was found in Tekirdag cekirdeksizi (TeCe) (0.89 and 0.90 g/L), while the lowest was detected in Victoria (Vi) (0.48 and 0.51 g/L). Total soluble solids (TSS) peaked in Horoz Karasi (HoKA) (21.90 degrees Brix), whereas it reached its lowest point in Big Perlon (BiPe) (14.1 degrees Brix). The tartaric acid content in the grape berries, ranging from 1.48 to 10.33 g/L for the two years, exhibited similar characteristics to malic acid, which ranged from 1.09 to 9.62 g/L and from 1.03 to 9.68 g/L for the two respective years. The succinic, malic, tartaric, citric, and oxalic acid contents were notably higher in the Kyoho (Ky) variety than in the other varieties. When examining the dendrogram of the contents of organic acid and sugar for similarities, it was evident that 16 out of the 17 grape varieties had a high degree of similarity, except for Alphonse Lavallee (AlLa) and HoKa. The similarity levels among the varieties ranged from 99.49% to 72.36%. The highest similarity (99.49%) was observed between the AlLa and Baris (Ba) varieties. The lowest similarity was observed among the AlLa, HoKa, and Ky varieties. In summary, this study underscores that certain table grape varieties grown in Ankara exhibit significant variations in valuable organic acids and sugars, which are associated with potential health benefits when considering human consumption.
Deciphering Terroirs' Code: Vineyard Site Selection for Phenolic Performance in 'kalecik Karası' Grape Cultivar (V. Vinifera L.)
(Springer, 2024) Canturk, Sevil; Kunter, Birhan; Keskin, Nurhan; Kaya, Ozkan
Understanding the complex interplay between environmental factors and grape quality is crucial for the viticulture industry, as it directly influences wine quality and the distinctiveness of products. This significance underpinned our comprehensive study, which aimed to dissect the relationships between 'terroir', including the altitude, regional climate, soil characteristics, vineyard management practice, and the composition of grapes in cv. 'Kalecik Karas & imath;' (Vitis vinifera L.). Six vineyard sites ranging from 115 to 1180 m altitude were studied. Total soluble solids (TSS, degrees Brix) titratable acidity, pH and color index of red grapes (CIRG) were evaluated as the main maturity indices and phenolic composition based on anthocyanin and tannin was analyzed. According to the results of the study, we deduced the critical importance of adopting region-specific viticultural practices tailored to the unique environmental conditions of each terroir. This approach not only optimizes grape quality but also accentuates the uniqueness of the wines produced, reflecting the inherent qualities of their origin. The highest altitude Nev & scedil;ehir (1180 m) showed high levels of total and extractable anthocyanin highlighting the region's favorable conditions for these compounds (355.26 mg kg(-1) and 364.00 mg kg(-1)), while exhibiting the second lowest skin tannin (1979.40 mg kg(-1) and 2180.78 mg kg(-1)) in both years. Particularly for cultivars like 'Kalecik Karas & imath;', our study demonstrated how specific terroirs could significantly affect their phenolic composition and, consequently, wine quality. By aligning viticultural practices with the distinct characteristics of each terroir, producers can enhance both the quality and distinctiveness of their wines. This emphasizes the necessity of ongoing research and adaptation in viticultural strategies to fully harness the potential of diverse grape varieties and terroirs, ensuring the production of high-quality wines that truly reflect their origin.
Drying Grapes After the Application of Different Dipping Solutions: Effects on Hormones, Minerals, Vitamins, and Antioxidant Enzymes in Gok Uzum (Vitis Vinifera L.) Raisins
(Mdpi, 2022) Keskin, Nurhan; Kaya, Ozkan; Ates, Fadime; Turan, Metin; Gutierrez-Gamboa, Gaston
(1) Background: Raisins contain a wide range of hormones, minerals, vitamins, and antioxidant enzymes that may contribute to the health benefits of consumers. (2) Methods: The aim of this research was to compare the hormone, mineral, vitamin, and antioxidant capacities of Gok uzum (Vitis vinifera L.) raisins immersed in oak ash (OA) and potassium carbonate (PC) dipping solutions before drying. (3) Results: Abscisic acid (ABA) (5751.18-11,868.40 ng g(-1)) and riboflavin (95.17-135.54 mg 100 g(-1)) were the most abundant hormone and vitamin quantified in Gok uzum raisins. Glutathione S-transferase (540.07-744.85 EU gr berry(-1)), 6-glucose phosphate dehydrogenase (214.50-317.43 EU gr berry(-1)), and glucose-6-phosphate dehydrogenase (208.25-241.86 EU gr berry(-1)) enzymes presented the highest antioxidant activity in the samples. Raisins obtained after drying by immersion in OA presented higher indol-3-acetic acid (IAA), ABA, salicylic acid (SA), cytokinins (CK), and zeatin contents; glutathione reductase (GR), glucose-6-phosphate dehydrogenase (G6PD), glutathione S-transferase (GST), 6 glucose phosphate dehydrogenase (6GPD), catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) enzymatic activity; vitamin B1, B2, B6, C, and A contents; and nitrogen (N), phosphorus (P), manganese (Mn), calcium (Ca), sulfur (S), potassium (K), iron (Fe), sodium (Na), and magnesium (Mg) levels compared to the grapes dried after PC applications. (4) Conclusions: Drying Gok uzum grapes after the application of OA dipping solution promotes a higher content of hormones, minerals, vitamins, and antioxidant enzymes compared to PC treatments. These results could help raisin producers to make decisions when using a dipping solution to dry grapes.
Effect of Foliar Spraying of Ascophyllum Nodosum Extracts on Grape Quality of 'tarsus Beyazi
(Springer, 2022) Topuz, Hasan; Keskin, Nurhan; Kiraz, Mehmet Erdem; Tarim, Guzin; Topuz, Fatih; Ozel, Nurcan; Kaya, Ozkan
In recent years, studies have shown that seaweed applications could prevent post-harvest berry drops in grapes and allow improvements in cluster and berry quality characteristics. This study was conducted on 'Tarsus Beyazi' grape cultivar, which was grown on its own root and goblet-trained, in the Tarsus district of Mersin Province, Turkey. Although 'Tarsus Beyazi' is an early and well-known cultivar, it does not attract much attention due to its genetic susceptibility to berry drop; however, it is an important grape genetic source. In this study, foliar spraying of seaweed (Ascophyllum nodosum [L.] Le Jolis) was applied to the vines of 'Tarsus Beyazi'. After the application, the force to separate the berries from the stalk, berry weight (g), berry width (mm), berry length (mm), cluster width (cm), cluster length (cm), cluster weight (g), titratable acidity (%,TA), total soluble solids (%,TSS), and pH, as well as leaf and berry mineral content, were determined. Based on our results, it was determined that seaweed application had positive effects on the cluster characteristics rather than the berry properties of the 'Tarsus Beyazi'. The difference between application and control grapevines was found to be significant for cluster width and weight. As compared to the control grapevines (11.16 cm), clusters were approximately 9.86% wider in the application grapevines (12.26 cm), and the difference in cluster weight was about 37 g between the mean value of the application (297.40 g) and the control (260.23 g) grapevines. To sum up, the use of seaweeds in 'Tarsus Beyazi' has made it possible to improve grapevine productivity and enhance berry quality, mostly in terms of cluster characteristics.
Evaluation of Clonal Variability of Berry Phenolics in Vitis Vinifera L. Cv. Kalecik Karasi
(Springer, 2022) Keskin, Nurhan; Kunter, Birhan; Celik, Hasan; Kaya, Ozkan; Keskin, Siddik
In clonal grapevine populations, genetic factors may have a significant effect on the amount of phenolic compounds in the grape berries. Thus, the capacity of the clones to produce distinctive chromatic profiles can be improved. This paper describes the phenolic contents and composition of grape berries as well as relationships among them for Kalecik Karasi clones to reveal their wine quality potentials. Seven individual polyphenols were quantified using high-performance liquid chromatography. The clones showed a significant difference (5.01 mg kg(-1) protocatechuic acid and 18.80 mg kg(-1) gallic acid) in berry phenolic compounds. Cluster analysis and multidimensional scaling were performed, and results showed that clones were clustered into three groups regarding phenolic compounds in the berries. Based on the phenolic compounds, 18 of the 23 clones were clustered into a group. Clones 16, 13, 8, and 2 were grouped together, while clone 7 was separated from the others. Including and excluding clone 7, approximately 40% phenotypic variation and 80% similarity were observed in 'Kalecik Karasi' clones, respectively. There were positive correlations between clones 2, 6, 7, 9, and 13 and p-coumaric, ferulic, gallic, and protocatechuic acids, as well as between clones 3, 5, 10, 14, 15, 34, 16, 19, and 20 and q-coumaric, vanillic, and syringic acid contents. Thus, it can be stated that multivariate methods can be used for clonal selection, and exclusive clones can be selected with high values of phenolic compounds in the future.
Exploring the Complete Chloroplast Genomes of Key Lamiaceae Species Uncovers the Secrets of Evolutionary Dynamics and Phylogenetic Relationships
(Springer, 2025) Furan, Mehmet Alp; Yildiz, Faruk; Kaya, Ozkan
Chloroplast genome analysis provides crucial insights into plant evolution, classification, and conservation strategies. This study aimed to conduct a comprehensive comparative analysis of chloroplast genome architecture, gene content, and evolutionary relationships among five species of Lamiaceae (Lavandula angustifolia, Mentha x piperita, Ocimum x africanum, Salvia japonica, and Thymus serpyllum). Complete chloroplast genome sequences were retrieved from the NCBI database and analyzed using a systematic bioinformatics pipeline. Genome annotation was performed using Geneious Prime software, while repetitive sequence analysis was conducted using Tandem Repeats Finder. Phylogenetic relationships were reconstructed using MEGA software, implementing both the DualBrothers model and Neighbor-Joining method. The analyzed genomes exhibited the characteristic quadripartite structure, with sizes ranging from 152,048 to 153,995 base pairs and GC content between 37.8 and 38.0%. Each genome contained 131-134 genes, including 50 protein-coding sequences, 8 rRNA genes, and 37 tRNA genes. Comparative analysis revealed region-specific GC content variations, with IR regions showing the highest (43.0-43.4%), followed by LSC (35.9-36.2%) and SSC regions (31.6-32.1%). Codon usage analysis demonstrated a significant bias toward T/C-ending codons, particularly TTT, AAA, and AAT, correlating with the high AT content. Notable variations were observed at the LSC/IR/SSC junction regions, attributed to IR expansion and contraction. Molecular clock analyses indicated consistent evolutionary rates across the studied species. These findings provide valuable insights into the molecular evolution of Lamiaceae chloroplast genomes and establish a foundation for future research in plant molecular biology, systematic studies, and conservation efforts.
Fine-Tuning Grape Phytochemistry: Examining the Distinct Influence of Oak Ash and Potassium Carbonate Pre-Treatments on Essential Components
(Mdpi, 2024) Kaya, Ozkan; Delavar, Hava; Ates, Fadime; Yilmaz, Turhan; Sahin, Muge; Keskin, Nurhan
Understanding the impact of pre-treatment methods on the phytochemical composition of grapes is essential for optimizing grape quality and producing raisins with desirable characteristics. Therefore, this study meticulously analyzed the impact of two distinct pre-treatment methods, oak ash and potassium carbonate (K2CO3), on the composition of essential phytochemical components in grapes. This research encompassed phenolic compounds, anthocyanins, phenolic acids, flavonoids, and phytoalexins. This study investigates the impact of pre-treatment methods, oak ash and K2CO3, on the phytochemical composition of grapes. Significant differences were observed in anthocyanins, flavonoids, phytoalexins, and phenolic acids between the treatments. Oak ash exhibited advantages in preserving specific compounds, including higher levels of anthocyanins, flavonols, flavones, flavanones, catechins, resveratrol, pterostilbene, and viniferin, compared to K2CO3. Notably, the delphinidin-3-O-glycoside content was significantly higher in the oak ash treatment. An analysis of phenolic compounds revealed distinctions in hydroxycinnamic acids, hydroxybenzoic acids, benzaldehyde, and phenylacetaldehyde. Additionally, gallic acid, vanillic acid, trans-caffeic acid, trans-p-coumaric acid, and (-)-epicatechin were significantly more prevalent in the K2CO3 treatment, while ferulic acid and quercetin were more prevalent in the oak ash treatment. These findings underscore the pivotal role of pre-treatment methods in shaping the phytochemical content of grapes, thus holding critical implications for grape-derived products' quality and potential health benefits.
Integrating Organic Fertilization and Soil Tillage Techniques To Enhance the Nutritional Attributes of "royal" Grapes (Vitis Vinifera L. Cv.)
(Wiley, 2024) Kaya, Ozkan; Ates, Fadime; Daler, Selda; Keskin, Nurhan; Turan, Metin
In the context of global efforts to improve food quality against the backdrop of climate change and increasing demands for food, this study sought to investigate the influence of tillage and fertilization methods on essential nutritional components. Thus, this extensive investigation into the variability of organic acid, sugar, and vitamin content within berries over the years 2020 to 2022 shows the critical influence of agricultural practices on the nutritional quality of grape. Our findings revealed significant fluctuations in the levels of various organic acids, with oxalic and propionic acids seeing a notable increase in 2022, while tartaric, citric, and maleic acids decreased. Similarly, a significant rise in sucrose, glucose, and fructose levels was documented by 2022, alongside a variable trend in vitamin content. The PCA results revealed a clear impact of tillage and organic amendments on the biochemical composition of Royal grapes. Heatmap findings confirmed the results obtained from PCA and showed that certain treatments resulted in high organic acid content, while others resulted in high sugar content. However, disc harrow and olive blackwater 2021 followed by disc harrow and Antep radish 2021 and no-tillage broccoli 2020 were the best treatments with a balanced distribution of organic acids, soluble sugars, and vitamins among all treatments. On the other hand, chisel and olive blackwater '20 was the treatment with the lowest ratio of organic acids, sugars, and vitamins, followed by chisel and Antep radish 2020. These results show that the concentration of organic acids, soluble sugars, and vitamins in grapes is more affected by the tillage method than the type of organic fertilizer used. To sum up, our study holds valuable implications for viticulture and agriculture at large, highlighting the potential to tailor farming practices for enhanced nutritional outcomes. Such advancements not only promise to elevate the quality of agricultural produce but also contribute to the broader objective of achieving food security and nutritional adequacy, thus offering a roadmap for future research and practice in sustainable agriculture and viticulture.
Investigation of Some Physicochemical Traits and Changes After Storage of Fruits Belonging To 'zivzik Pomegranate Genotypes Grown in Siirt, Turkey
(Springer, 2022) Ozrenk, Koray; Turk, Bilge; Sen, Fatih; Keskin, Nurhan; Kaya, Ozkan
Pomegranate genotypes called 'Zivzik' are widely grown in Siirt, Turkey, and these genotypes have sweet, tart, and sour fruits. This study was carried out to determine the physicochemical traits of fruits belonging to 'Zivzik' pomegranate genotypes, as well as changes in fruit characteristics after storage. Sweet, tart, and sour 'Zivzik' pomegranate genotypes were harvested in Sirvan and Pervari districts of Siirt. The fruits were placed in modified atmosphere packages and kept at 6 degrees C and 90% relative humidity for 3 months. Some physicochemical traits were determined in both harvested and stored pomegranate fruits. Fruit weight (280.8 g), berry weight (0.41 g), fruit width (84.5 mm), and fruit length (8.57 mm) of the fruits of the sweet pomegranate genotype were found to be higher than in the other genotype fruits. However, the total soluble solids content (17.57%), titratable acid content (3.02 g/100 ml), total phenol content (163.43 mg GAE/100 ml), and antioxidant activity (49.95 mu mol TE/ml) of the fruits of the sour pomegranate genotype were higher than in fruits of other genotypes. There were differences between pomegranate genotypes in fruit peel color and berry size. After storage, there was a significant decrease in the titratable acid content of fruits in all genotypes, while their total soluble solids, total phenol content, and antioxidant activities increased. However, no significant change was found in fruit peel color in any genotype. Consequently, there were differences between the physicochemical traits of the fruits belonging to the sweet, tart, and sour 'Zivzik' pomegranate genotypes, but there were no significant changes in these traits after storage.
Modulation of Biochemical Traits in Cold-Stored 'Karaerik’ Grapes by Different Edible Coatings
(Mdpi, 2025) Keskin, Nurhan; Karakus, Sinem; Hatterman-Valenti, Harlene; Kaya, Ozkan; Cavusoglu, Seyda; Tekin, Onur; Karadogan, Birol
Understanding the effects of edible coatings on postharvest quality and shelf life of 'Karaerik' grapes is crucial for improving storage outcomes and reducing losses. However, limited information exists regarding the effectiveness of different coating materials on this regionally significant variety. In this study, 'Karaerik' grapes were treated with carboxymethyl cellulose (CMC) and locust bean gum (KB) coatings and stored under cold conditions (0 +/- 0.5 degrees C, 90-95% relative humidity) for 0, 25, 45, and 60 days. Storage duration and coating treatments significantly affected most physical, physiological, and biochemical parameters. During storage, grape weight loss progressively increased, reaching 9.60% in the control by day 60. Coatings slightly reduced this loss, with KB showing the lowest (5.11%) compared to the control (5.69%). Respiration initially declined but surged again at day 60, especially in the control (96.4 mu mol CO2/kg center dot hour), while coatings helped mitigate this rise. Ethylene release remained unchanged. A slight pH decline (similar to 4.6%) was observed in the control, while KB-treated grapes maintained higher pH and lower acidity. Soluble solids remained stable across treatments. Color changed notably during storage: a* nearly doubled (more redness), b* increased (less blue), and chroma (C*) declined by similar to 25%, especially in uncoated grapes. Total sugar dropped by similar to 43% in KB-treated grapes, with the control retaining the most. Tartaric acid decreased by similar to 55%, notably in KB samples. Antioxidant activity and total phenolics declined significantly (similar to 66%) in the control. CMC coating better-preserved antioxidant capacity, while the control showed the highest phenolic levels overall. Ferulic, gallic, and chlorogenic acids increased toward the end of storage, particularly in coated grapes. In contrast, rutin and vanillic acid peaked mid-storage and were better preserved in the control. The heatmap showed significant metabolite changes in fruit samples across 0D, 25D, 45D, and 60D storage periods under CMC, CNT, and KB treatments, with distinct clustering patterns revealing treatment-specific biochemical responses. The correlation matrix revealed strong positive relationships (r > 0.70) between total sugar, glucose, and fructose levels, while ethylene showed significant negative correlations (-0.65 to -0.85) with maturity index, pH, and total soluble solids, indicating interconnected metabolic pathways during fruit ripening and storage. We conclude that edible coating selection significantly influences grape biochemical stability during cold storage, with CMC emerging as a superior choice for maintaining certain quality parameters.
Pollinator Diversity and Phenological Interplay: Exploring Mineral, Hormonal, Sugar, and Vitamin Contents in Vitis Vinifera L. Cv Bozcaada Çavuşu
(Mdpi, 2024) Kaya, Ozkan; Delavar, Hava; Ates, Fadime; Sahin, Muge; Keskin, Nurhan; Yilmaz, Turhan; Hatterman-Valenti, Harlene
Unraveling the intricate physiological and biochemical intricacies associated with female dominance in grape berries across diverse developmental stages is imperative for optimizing grape production and ensuring the attainment of high-quality yields. This study conducted a thorough analysis of grape berries across phenological stages (BBCH-79, BBCH-81, BBCH-89) and cultivars. At BBCH-89, Bozcaada & Ccedil;avu & scedil;u*Vasil & acirc;ki demonstrated the highest berry weight and total soluble solids (TSS) levels, emphasizing its enological potential. Acidity peaked at BBCH-79 (28.16) and declined at BBCH-89 (6.11), signaling a shift towards lower acidity in later stages. Bozcaada & Ccedil;avu & scedil;u*Vasil & acirc;ki consistently showed the highest maturity index (MI). Mineral content variations were observed across nitrogen (N), calcium (Ca), potassium (K), phosphorus (P), magnesium (Mg), sulfur (S), iron (Fe), manganese (Mn), boron (B), zinc (Zn), and copper (Cu), with Bozcaada & Ccedil;avu & scedil;u*Vasil & acirc;ki often having the highest concentrations, particularly in potassium, calcium, and boron. Hormonal analysis revealed a significant surge in concentrations at BBCH-89, with Bozcaada & Ccedil;avu & scedil;u*Vasil & acirc;ki standing out. Notably, Indole-3-acetic acid (IAA) concentrations increased by 106%, and abscisic acid (ABA) levels peaked at BBCH-79 with a 38% increase in Bozcaada & Ccedil;avu & scedil;u*Kuntra. Sugar content analysis showed variations in fructose, glucose, sucrose, rhamnose, xylose, galactose, and arabinose levels across sampling times and cultivars. Bozcaada & Ccedil;avu & scedil;u*Vasil & acirc;ki consistently exhibited higher sugar levels, especially at BBCH-81 and BBCH-89. Vitamin concentrations varied temporally and among cultivars, with BBCH-89 displaying the highest vitamin A concentration (6.24 mg/100 g FW), and Bozcaada & Ccedil;avu & scedil;u*Vasil & acirc;ki often exhibiting maximum values for vitamin B1, B2, B6, and C. Further research and targeted cultivation practices focusing on the unique attributes of Bozcaada & Ccedil;avu & scedil;u*Vasil & acirc;ki could enhance grape production efficiency, emphasizing its potential contribution to achieving consistently high-quality yields across various phenological stages.
Socio-Demographic and Attitudinal Factors Influencing Household Fruit and Vegetable Purchasing Frequency in Eastern Türkiye
(BMC, 2025) Yalvac, Omer; Keskin, Nurhan; Terin, Mustafa; Hajizadeh, Hanifeh Seyed; Kaya, Ozkan
BackgroundThis study examines the relationship between households' fruit and vegetable purchasing frequency and their socio-demographic characteristics and attitudes, with a focus on Eastern T & uuml;rkiye's Van province, a region underrepresented in existing literature.ObjectiveTo explore how socio-demographic and attitudinal factors influence the frequency of household fruit and vegetable purchases.MethodsMethodologically, the research employs a Chi-square test of independence to compare households' fruit and vegetable purchasing frequencies across four categories: never, twice a month, once a week, and more than once a week. To further analyze the determinants of purchasing frequency, an ordered probit model was utilized. This econometric approach was applied to obtain coefficients used in calculating marginal effects and probabilities.ResultsThe empirical results reveal significant influences of various household characteristics on fruit and vegetable purchasing frequency. Household income, fruit and vegetable expenditure, employment and insurance status of the household head, perception of sufficient fruit and vegetable consumption within the household, and fruit and vegetable consumption by children in the household were found to positively affect the frequency of household fruit and vegetable purchases. Conversely, the age of the household head was found to negatively impact the frequency of fruit and vegetable purchases. Given the behavioral elements involved in food purchasing, this study also incorporates attitudinal and perceptual factors that may reflect bounded rationality beyond classical utility theory.ConclusionThis research contributes to both public health and behavioral economics literature by integrating socio-demographic and psychological variables into the analysis of purchasing behavior. The findings suggest that multifaceted approaches may be necessary to effectively increase fruit and vegetable consumption, including economic interventions, educational programs, and targeted interventions for specific demographic groups such as older adults. The results also offer empirical support for developing regionally tailored strategies in under-studied areas like Van.
Study of Volatile Organic Compounds of Two Table Grapes (Cv. Italia and Bronx Seedless) Along Ripening in Vines Established in the Aegean Region (Turkey)
(Mdpi, 2022) Kaya, Ozkan; Incesu, Melek; Ates, Fadime; Keskin, Nurhan; Verdugo-Vasquez, Nicolas; Gutierrez-Gamboa, Gaston
(1) Background: Italia is a seeded grape variety widely cultivated in the Aegean Region in Turkey, whereas Bronx Seedless is a seedless grape variety, preferred by consumers due to its pink berries and interesting flavor. The goal was to study the volatile compounds of these table grapes throughout berry ripeness. (2) Methods: The volatile compounds were analyzed by GC-MS in six different phenological stages (3) Results: Bronx Seedless grapes presented a higher content of seven terpenes, three aldehydes, one fatty acid, three alcohols, one C6 compound, total aldehydes and total alcohols, and a lower content of eleven terpenes, one fatty acid, four esters, one alcohol, four C6 compounds and its total content than Italia table grapes. The concentration of most of the volatile compounds analyzed increased from "begin of berry touch" to "berries ripe for harvest" stages. Terpenes content in both varieties at harvest was lower than 1.0 mg L-1. beta-ionone presented the highest odor activity value (OAV) in both varieties. Bronx Seedless grapes presented higher OAV for (Z)-3-hexenal and cedrol, and lower hexanal to (E)-2-hexenal ratio than Italia grapes. (4) Conclusions: Both varieties could be classified as neutral aromatical varieties and it is probable that to achieve a better aromatic quality, Bronx Seedless should be harvested later than Italia.
Timing Matters, Not Just the Treatment: Phenological-Stage Effects of Seaweed and Ethanol Applications on Postharvest Quality of 'Tarsus Beyazı' Grapes
(Mdpi, 2025) Tarim, Guzin; Karakus, Sinem; Keskin, Nurhan; Hatterman-Valenti, Harlene; Kaya, Ozkan
In the context of increasing consumer demand for high-quality, residue-free fruits and the growing emphasis on sustainable postharvest technologies, identifying effective, eco-friendly treatments to maintain grape quality during storage has become a critical focus in modern viticulture. Over the course of this study, we examined the influence of seaweed extract (derived from Ascophyllum nodosum) and ethanol-based postharvest treatments on the postharvest quality of the 'Tarsus Beyaz & imath;' grape. The seaweed extract was applied at six specific phenological stages according to the BBCH scale: BBCH 13 (3rd-4th leaf stage, 0.40%), BBCH 60 (first flower sheath opening, 0.50%), BBCH 71 (fruit set, 0.50%), BBCH 75 (chickpea-sized berries, 0.50%), BBCH 81 (start of ripening, 0.60%), and BBCH 89 (harvest maturity, 0.60%). After harvest, grape clusters were subjected to four different postharvest treatments: untreated control, control + ethanol (20% ethanol immersion for 10 s), seaweed extract alone (preharvest applications only), and seaweed extract + ethanol (combining both preharvest and postharvest treatments). Grapes were stored at 0-1 degrees C and 90-95% RH for three weeks, followed by a shelf-life evaluation period of three days at 20 degrees C and 60-65% RH. The findings revealed that seaweed treatments, especially when applied during cluster formation and berry development, effectively mitigated physiological deterioration, preserving stem turgidity and enhancing berry firmness. In contrast, ethanol showed variable responses, occasionally exerting negative effects, with only marginal benefits observed when applied at optimal developmental stages. Both the type and timing of application emerged as critical determinants of key quality attributes such as weight loss, decay incidence, and must properties (TSS, pH, TA). Correlation and heat map analyses indicated the interrelationships among these parameters and the differential impacts of treatments. These results suggest that phenological-stage-specific seaweed applications hold significant potential as a sustainable strategy to extend the storage life and maintain the market quality of 'Tarsus Beyaz & imath;' grapes.