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    Phytochemical and Antioxidant Variability in Some Black Mulberry, Chokeberry, and Elderberry Cultivars in Relation to Cultivar, Plant Part, and Extraction Solvent
    (Mdpi, 2025) Zengin, Rukiye; Ugur, Yilmaz; Erdogan, Selim; Yavuz, Cigdem; Hatterman-Valenti, Harlene; Kaya, Ozkan
    Polyphenols and flavonoids are key bioactive compounds with significant antioxidant properties, making them crucial for human health and nutraceutical applications. However, their extraction efficiency and concentrations are influenced by multiple factors, including plant part, cultivar, and solvent selection. Therefore, this study investigated the effects of plant part, cultivar, and solvent type on the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant capacity (ABTS and CUPRAC assays) in different extracts from black mulberry, chokeberry, and elderberry. In all three species, the leaves exhibited significantly higher phytochemical and antioxidant properties than the fruits, with an average increase of 62.8-133.4% in the TPC and 55.4-390.3% in the TFC. Among genotypes, G & uuml;m & uuml;& scedil;hac & imath;k & ouml;y Horum and Tohma Medik (black mulberry), Viking and Nero (chokeberry), and Tokat (T1) (elderberry) demonstrated the highest levels of bioactive compounds, while & Scedil;elale Karadut, Aron, and Haschberg exhibited the lowest values. Solvent selection played a crucial role, with methanol:water:HCl emerging as the most effective extraction medium, increasing the TPC by 27.5-46.3%, the TFC by 28.3-67.6%, and the antioxidant capacity (ABTS and CUPRAC) by up to 94.2% compared to water extraction. These findings indicate the significance of leaf-based bioactive compound extraction and optimized solvent selection for maximizing antioxidant yields. The results of this study also have important implications for both fruit cultivation and human nutrition, highlighting the potential of leaves as a valuable source of polyphenols and antioxidants.
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    Phytochemical stability and bioavailability of black mulberry, chokeberry, and elderberry during gastrointestinal digestion and their implications for human nutrition
    (Scientific Scholar Llc, 2025) Zengin, Rukiye; Ugur, Yilmaz; Erdogan, Selim; Hatterman-Valenti, Harlene; Kaya, Ozkan
    Understanding the fate of bioactive compounds during human digestion is crucial for translating berry consumption into actual health benefits. In this study, we investigated the effects of different digestion methods and gastrointestinal environments on the phytochemical content and antioxidant capacity of the black mulberry (BMF), chokeberry (CF), and Elderberry (EF) fruit and leaf samples. Pre-digest and digest methods were applied to evaluate changes in phenolic compounds and antioxidant capacity under simulated oral, gastric, and intestinal conditions. Based on our findings, elderberry demonstrated the highest total phenolic content in the intestinal phase (44.0 mg GAE/g), while chokeberry showed the highest antioxidant capacity, with cupric reducing antioxidant capacity (CUPRAC) values of 134.3 mg TE/g and 2,2 '-azinobis (3-ethylbenzothiazoline 6-sulfonate) (ABTS) of 104.8 mg TE/g. Anthocyanin stability analysis revealed severe degradation of cyanidin-3-O-glucoside during digestion, with reductions of 68.9%, 70.4%, and 82.7% in oral, gastric, and intestinal phases respectively from initial concentrations of 2106.12 mg/100g. Notably, quercetin content increased dramatically from 0.8-0.9 mg/100g to 16.8 mg/100g in BMF during intestinal digestion, while catechin showed substantial reduction from 1151.4 mg/100g in elderberry samples. This research elucidates the complex dynamics of phytochemical stability and bioavailability during gastrointestinal digestion, providing valuable insights for understanding the potential health benefits of these berries in human nutrition and suggesting opportunities for developing targeted delivery systems to enhance the stability of beneficial compounds throughout the digestive process.
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    Sun-Drying and Melatonin Treatment Effects on Apricot Color, Phytochemical, and Antioxidant Properties
    (Mdpi, 2025) Zengin, Rukiye; Ugur, Yilmaz; Levent, Yasemin; Erdogan, Selim; Hatterman-Valenti, Harlene; Kaya, Ozkan
    Post-harvest deterioration of fruit quality represents a significant challenge in the dried fruit industry, particularly affecting the preservation of nutritional compounds and sensory attributes during the drying process. This research examined the potential protective effects of exogenous melatonin supplementation on the preservation of selected quality metrics and antioxidant characteristics in sun-dried apricots, utilizing a comparative analysis across disparate melatonin concentrations (10, 100, and 1000 mu M). Our research findings demonstrated that melatonin treatment, particularly at 100 mu M concentration, significantly enhanced quality preservation in sun-dried apricots. Specifically, the treatment resulted in improved color retention (increased L*, a*, and b* values), reduced oxidative stress markers (MDA and H2O2), and optimized sugar composition (glucose: 18.99 g/100 g, fructose: 12.58 g/100 g, sucrose: 15.52 g/100 g). The melatonin treatment at 100 mu M concentration proved particularly effective, revealing the most significant results. Specifically, this concentration resulted in the highest beta-carotene levels, reaching 223.07 mg/kg. These findings suggest promising applications for commercial-scale implementation through either dipping or spraying methods. The non-toxic nature of melatonin and its demonstrated efficacy in preserving fruit quality parameters position it as a valuable post-harvest treatment option in the fruit supply chain. This research contributes significantly to advancing sustainable post-harvest preservation strategies, though further investigation into melatonin stability and standardization of application protocols remains necessary for optimal commercial implementation.
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    Temporal shifts in phenolic composition and antioxidant responses of two Turkish grape cultivars ('Kureyş' and 'Tahannebi') during berry development
    (Springer, 2025) Ates, Sevim; Ugur, Yilmaz; Zengin, Rukiye; Demir, Nurullah; Dogan, Tugba; Erdogan, Selim; Hatterman-Valenti, Harlene
    Phenolic compounds play a vital role in grape quality, antioxidant potential, and stress resilience; therefore, tracking their variation across developmental stages is essential for both viticultural practices and functional food production. The aim was to characterize variety-specific phenolic dynamics and antioxidant activity changes to guide optimized harvest timing and functional quality improvement. In this regard, present study evaluated the accumulation patterns of phenolic compounds and antioxidant activity across berry developmental stages from EL-27 (Eichhorn-Lorenz phenological scale) to EL-41 in two grape (Vitis vinifera L.) cultivars, 'Kurey & scedil;' and 'Tahannebi'. A total of 17 phenolic compounds were quantified by high-performance liquid chromatography (HPLC-DAD), and total phenolic content (TPC) and antioxidant activity were determined by Folin-Ciocalteu, ABTS (2,2 '-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid), and DPPH ((1,1-diphenyl-2-picrylhydrazyl) assays. Significant differences (p < 0.001) were observed between varieties, phenological stages, and their interactions for all analyzed compounds. In general, phenolic concentrations peaked during the early stages (EL-27: K1, T1) and declined progressively through EL-31 (K2, T2), EL-33 (K3, T3), EL-35 (K4, T4), EL-36 (K5, T5), EL-38 (K6, T6), and EL-41 (K7, T7). 'Kurey & scedil;' consistently exhibited higher levels of gallic acid, catechin, chlorogenic acid, and caftaric acid, with chlorogenic acid decreasing by 98.8% from EL-27 to EL-41. In contrast, 'Tahannebi' showed lower initial concentrations but retained specific compounds like ellagic acid and p-coumaric acid longer. Multivariate analyses revealed distinct metabolic clustering. PCA explained 85% of total variance, with early-stage samples characterized by enriched antioxidant profiles. Correlation analysis indicated strong associations among TPC, antioxidant capacity (ABTS, and DPPH) assays, suggesting coordinated biosynthetic regulation. Hierarchical clustering clearly distinguished early high-phenolic samples (e.g., K1, T2) from late-stage samples (K7, T7) with reduced biochemical activity. Overall, this study highlights genotype-dependent differences in phenolic composition and antioxidant capacity during grape ripening, offering integrated insights into their physiological basis and implications for harvest optimization, nutraceutical enhancement, and breeding for functional quality.