Browsing by Author "Karatas, Arzu"

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Effect of Pre-Harvest Organic Cytokinin Application on the Post-Harvest Physiology of Pepper (Capsicum Annuum L.)
(Mdpi, 2021) Cavusoglu, Seyda; Sensoy, Suat; Karatas, Arzu; Tekin, Onur; Islek, Firat; Yilmaz, Nurettin; Mlcek, Jiri
Peppers are cultivated in almost all provinces in Turkey, making up approximately 7% of the world's production. In this study, the effects of pre-harvest cytokinin application on the postharvest physiology of pepper (Capsicum annuum L.) fruits (cv. Akra and Melek F1) grown in ecological conditions in Turkey (Van, eastern Turkey) were investigated. During the growing period, organic cytokinin(nytrozine) at two concentrations (50 and 100 ppm doses) was applied by spraying. Peppers were harvested in green maturity and then stored at 12 degrees C for 28 days. Changes in color, respiration rate, exogenous ethylene amount, antioxidative enzyme analysis (SOD, CAT and APX), lipid peroxidation, total phenolic content (TP) and antioxidant activity (AA) were determined just after the harvest and then at the 7th, 14th, 24th and 28th days. L* values for both varieties and the control sample had fluctuations during storage, and they slightly decreased after 28 days, except for the end value of cv. Melek F1 with a 50 ppm addition. In terms of respiration rate values, the difference between applications was found to be statistically significant, except for the 14th and 24th days of storage, for cv. Akra F1; and the 0th and 28th days for cv. Melek F1, respectively. It was observed that cytokinin can delay aging in peppers of both cultivars stored for 28 days. As a result, as the used cytokinin has an organic origin, is not synthetic and does not have a negative effect on human health, it can be used safely and without a significant loss of quality characteristics for peppers. These applications have positive effects on in-package gas composition, antioxidative enzymes, lipid peroxidation, total phenolics and total antioxidant activity.
Green Synthesis of Silver Nanoparticles from Melanoleuca Grammopodia: Changes in Bioactive Components, Antidiabetic Properties and Bioaccessibility
(Tubitak Scientific & Technological Research Council Turkey, 2025) Acar, Ismail; Okumus, Emine; Karatas, Arzu
Green synthesis of silver nanoparticles (AgNPs) using plant materials allows the production of low-cost and biocompatible nanoparticles without the use of toxic compounds or solvents. In this study, biogenic AgNP/Mg nanoparticles were synthesized using the Melanoleuca grammopodia mushroom. Vitamin C and E contents of the mushroom were 42.6 mg/g and 26.82 mg/g, respectively. FTIR analysis revealed the reducing and stabilizing effects of bioactive components present in M. grammopodia mushroom extract. SEM micrographs showed that the nanoparticles were spherical in form and the EDX spectrum confirmed the presence of the characteristic metallic silver peak at 3.0 keV. A significant reduction in the amounts of phenolic compounds in the mushroom extract and nanoparticles was observed after in vitro gastrointestinal digestion (p < 0.05). The bioaccessibility values of nanoparticles for gallic acid, caffeic acid, syringic acid and protocatechuic acid were determined as 33.46%, 43.25%, 32.18% and 41.49%, respectively. A significant increase in thermal resistance, antioxidant activity (22.50 mg/mL), antilipid peroxidation (4.41 mg/mL), antidiabetic properties (6.02 mg/mL) and bioaccessibility of AgNP/Mg compared to the mushroom extract was detected. This is the first study in which the bioactive components of the M. grammopodia mushroom species were determined and changes and developments in the synthesized nanoparticles were compared with the mushroom extract. The results revealed that this mushroom species and its silver nanoparticles may be a natural and valuable resource with potential applications, especially in the fields of chemistry, pharmacology, and medicine.