Browsing by Author "Hatterman-Valenti, Harlene"

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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.
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.
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.