Yazar "Yoldas, Taner" seçeneğine göre listele
Listeleniyor 1 - 4 / 4
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Comparison of Chemical Contents of Extracts in Different Solvents of Propolis Samples Produced in Duzce Province(Düzce Üniversitesi, 2020) Dönmez, Mert; Karadeniz, Şeref; Yoldas, Taner; Aydın, Gülşah; Karagül, Pınar; Aksu, Osman; Göç Rasgele, PınarObjective: Although the volatile components in the propolis composition are in very low concentration, they are extremely important for the characterization of propolis due to their aroma-giving properties and various biological activities. Since propolis is a product obtained from plants, its chemical composition depends on the local plant flora and the geographical and climatic characteristics of the region where the sample is collected. Therefore, different propolis samples can differ completely in terms of their chemistry and biological activities. Propolis extracts obtained by using different solvents have different contents. For this reason, the content of antioxidants varies, which causes differences in phenolic and flavonoid amounts. In the study, it was aimed to determine the efficacy of different propolis extracts produced as a result of beekeeping activities in Düzce province by comparing the chemical content. Material-Method: The extracts of propolis collected from Düzce province were prepared using ethanol, water and PEG400 – water solvents. In the study carried out, the volatile components of three different extracts of propolis samples obtained from hives belonging to Yığılca Region were examined with LC-MS/MS, GC-MS UV. The determination of the total phenolic component (TPC) level was carried out with the Folin-Ciocalteu reagent, and the total flavonoid content (TFC) level with the AlCl3 based method.Results: Major volatile constituents of Ethanolic extract; Diphenyl-1,2,5-oxadiazole (86.11%) and Benzenepropanoic acid ethyl ester (6.3%), Major volatile components of PEG400-water (50% - 50%) extract; 4-vinyl-2-methoxy-phenol (40.40%), Benzyl benzoate (17.16%), Methyl benzyl ketone (16.87%) ve Ethyl 3-methylnaphtho[1,2-c]pyrrole-1-carboxylate (14.32%), major volatile components of water extract; Benzyl Alcohol (79.91%) ve 4-vinyl-2-methoxy-phenol (8.86%). The highest TPC level was in ethanolic extract with 23,192.45 ± 396.54 mgGAE/100 g. Similarly, the highest TFC was found in ethanolic extract (7,190.12 ± 203.85 mgQE/100g). The water extract had the lowest levels at both TPC and TFC levels.Conclusion: It has been concluded that the highest phenolic content of propolis, which has recently begun to find an important use in the food and health sector, is obtained by ethanol extraction. When evaluated in terms of the obtained results from all methods, it is listed as Etanolic extract> PEG400> water extract. Further studies should be done using different solvents in order to extract as much of the components from propolis as possible.Öğe Hayvanlarda Soğuğa Dayanıklılık: Çift Yaşarların Kriyobiyolojisi(2022) Yoldas, Taner; Erişmiş, Uğur CengizOrganizmalar yaşamlarını devam ettirebilmek için abiyotik çevresel koşullara uyum sağlarlar. Özellikle ortam sıcaklığındaki değişimler; canlıların beslenme, üreme, gelişim ve morfolojileri üzerinde etkilidir. Sıra dışı sıcaklık değişimleri özellikle ektotermik hayvanlar için ölümcül olabilir. Karasal ektotermler. doğada donma noktasının altındaki sıcaklıklarda hayatta kalabilmek için davranışsal, fizyolojik ve biyokimyasal bazı özel stratejiler geliştirmişlerdir. Bazı türler göç ederek su ya da toprak altında kış uykusuna yatmak suretiyle dondurucu sıcaklıklardan kaçınırlar. Bazıları ise donma koşullarına maruz kalarak kışı geçirmek zorundadırlar. Genel olarak dondurucu soğuğa dayanıklılık donmadan kaçınma (süper soğuma) ve donma toleransı stratejilerine bağlıdır. Donmadan kaçınma durumunda vücut sıvılarının donma noktasının altındaki sıcaklıklarda sıvı formu korunurken donma toleransı stratejisini kullanan canlılarda ise vücutlarındaki toplam suyun %50’sinden fazlasının donması tolere edilebilir. Karasal hibernatör hayvanlardan bazı amfibi ve sürüngen gruplarında da tespit edilen donma toleransı stratejisi onların dondurucu kış koşullarında hayatta kalmalarını sağlamaktadır. Bu özel türler kriyoprotektif mekanizmaları ile donmanın ölümcül etkilerinden korunurlar. Donma süresince yaşamsal faaliyetleri tamamen duran bu hayvanlar çözündükten sonra kısa bir süre içerisinde de normal yaşama dönerler. Bu mucizevi mekanizmanın araştırılması yalnızca hayvanların karmaşık adaptasyonunu açıklamakla kalmaz, aynı zamanda doku ve hücre kriyoprezervasyon teknolojisine de kaynak sağlar. Bu derleme amfibilerin donma toleransı stratejilerine dair bilgiler sunarak henüz yeterince çalışılmamış bu konuda araştırma yapmak isteyenlere katkı sağlayacaktır.Öğe Investigation of Some Quality Criteria in Chestnut Honey of Düzce Province(Düzce Üniversitesi, 2023) Yoldas, Taner; Karagül, Bora; Düvenci, Elif SineHoney is a natural food source that has been consumed by humans for thousands of years and has an important place in various cultures. Chestnut honey is an important type of honey produced in Düzce province. Determining the quality and purity of honey ensures that consumers have access to safe, high-quality honey. The control criteria for the suitability of honey for human health consumption are defined in the Turkish Food Codex Communiqué on Honey (2020/7). Düzce University Scientific and Technological Research Application and Research Center (DÜBİT) responds to requests for honey analysis for non-commercial, internal quality control purposes. In this study, the results of honey samples produced in the province of Düzce and analyzed in the laboratories of DÜBİT were examined according to the criteria of the Turkish Food Codex Communiqué on Honey and an evaluation of the results was carried out. According to the test results, 38%, 20% and 16% of the samples were found to be unsuitable for the quality criteria, especially for the sugar profile, conductivity and proline parameters, respectively. Additionally, pollen analysis of 13% of the honey samples revealed pollen densities that did not match the declared plant family. From a public health point of view, it is important to consume high-quality, reliable and natural honey products. Therefore, quality control of bee products should be carried out from the producer to the consumer.Öğe Response of Anatolian mountain frogs (Rana macrocnemis and Rana holtzi) to freezing, anoxia, and dehydration: Glucose as a cryoprotectant(Academic Press Inc Elsevier Science, 2021) Yoldas, Taner; Erismis, Ugur CengizCryoprotectants play an essential role in the survival of some amphibians in response to different stress conditions such as freezing, anoxia, and dehydration. Glucose is one of the cryoprotectants important for freeze-tolerant frogs. The aim of the present study was to investigate the survival strategies of Anatolian mountain frogs (Rana macrocnemis and Rana holtzi), which are terrestrial hibernators, by examining the changes in glucose and water content in some tissues at subzero temperatures. In the current study, animals were exposed to freezing (-2.5 degrees C), anoxia, and dehydration treatments. During these treatments, all frogs survived. The glucose levels in the plasma, liver, and skeletal muscle and the water content of the tissues were measured during the freezing, anoxia, and dehydration. Changes in body weight were also recorded in both species. During the freezing, a 3.3-fold increase was seen in the blood glucose level of R. macrocnemis (1.35 +/- 0.25 to 4.45 +/- 0.51 mu mol mL(-1)), whereas the blood glucose level of R. holtzi exhibited a 4.5-fold increase (1.90 +/- 0.25 to 8.67 + 2.22 mu mol mL(-1)). In the liver, a 6.7-fold increase was seen in the glucose level of R. macrocnemis (5.66 +/- 0.15 to 38.27 +/- 8.53 mu mol g(-1)) and the increase in R. holtzi was approximately 6.0-fold (2.25 +/- 0.46 to 13.36 +/- 1.32 mu mol g(-1)) during freezing. The liver glucose levels of both species also increased significantly in response to the anoxia and dehydration. In both species, the glucose levels of the skeletal muscle were found to be higher in dehydration than with freezing and anoxia. In conclusion, our results suggest that glucose may be identified as an important cryoprotectant that plays an important role in the survival of Anatolian mountain frogs during extreme conditions.
