Browsing by Author "Olgun Ç."

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Antimicrobial activity and chemical composition of coriander & galangal essential oil
(2017-07-01) Özkinali S.; Şener N.; Gür M.; Güney K.; Olgun Ç.
Essential oils were obtained from Coriandrum sativum and Alpinia officinarum through steam distillation method in this study. Antimicrobial activities of the obtained essential oils were investigated by using minimum inhibitory concentration (MIC) test by against 18 different species microorganisms. It was found that the C. sativum had strong antimicrobial activities against the 14 tested microorganism and A. officinarum oils showed strong antimicrobial activity against the 7 tested microorganisms. Furthermore, the contents of the essential oils were determined with GC-MS analyses. The most abundant compounds of essential oils of A. officinarum and C. sativum were determined as 28.4% eucalyptol and 69.4% linalool. As a result, it can be easily said that the essential oils of C. sativum and A. officinarum can be used as antimicrobial protector in related fields.
Characterization and Comparison of Some Kraft Lignins Isolated from Different Sources
(2023-05-01) Olgun Ç.; Ateş S.
Lignin characteristics are significantly affected by kraft processing and isolation conditions. In the studies carried out in this context, commercial lignins or isolated lignins from industrial black solutions are generally preferred. In this study, in order to conduct more comprehensive research, three lignin samples were isolated from kraft black liquor obtained from laboratory cooking trials of pine, poplar, and wheat straw chips, representing softwoods, hardwoods, and annual plants, respectively, according to efficient pulping studies. In addition, another lignin-containing industrial waste was provided from a pulp mill (OBL). The acidification method was applied for isolating lignin from black liquor samples. After isolating the lignin samples from different sources, they were characterized and compared with the commercially available kraft lignin sample (Indulin AT). Total phenolic groups, carboxyl groups, purity, functional groups, nitrobenzene oxidation products, molecular weight, thermal stability, and element contents were analyzed. The isolated lignin samples (except wheat straw) were as pure as commercial lignin. Since the wheat straw was agricultural waste and an annual plant, inorganic elements such as P, K, and Si were more abundant than in the other samples. However, the polydispersity and molecular weight of all of the isolated lignin samples were higher than those of commercial lignin. Because the ash contents of the lignin samples for pine, poplar, OBL, and indulin AT were between 1 and 3%, they can be used for high-value applications. In particular, despite some disadvantages, wheat straw lignin has greater potential for use in extruders than softwood lignins due to their syringyl content.
Chemical composition and antimicrobial activity in cold press oil of fennel, anise, white and black mustard seeds
(2017-07-01) Olgun Ç.; Özkan O.; Güney B.; Pattabanoglu E.; Güney K.; Gür M.
In this study, the cold press oil components and antimicrobial activities of fennel (Foeniculum vulgare) and anise (Pimpinella anisum) and white mustard (Sinapis alba) and black mustard (Brassica nigra) species seeds, which are widely used by the people for alternative medicine, were determined. F. vulgare, P. anisum, S. alba and B. nigra species seeds were obtained from cultivated areas in central Anatolia in Turkey. The oil was extracted by using a screw press (MP-001 Cold Press, Turkey), and the volatile oil components and fatty acid components in these oils were analysed by GCMS and total phenolic content, total flavonoid content and antioxidant activities by DPPH and FRAP (%) method were determined. Antimicrobial activities of obtained oils were investigated by using minimum inhibitory concentration (MIC) test by against 18 different species microorganisms. In the GCMS results, F. vulgare and P. anisum oils were found to be the most abundant components which were anethole (89.74%, 88.95%, respectively). According to these results, the plants oils didn’t show any antimicrobial activities against tested microorganisms. However especially white and black mustard oils showed strong antioxidant activity when compared with artificial antioxidants.
Chemical composition and antioxidant properties of some industrial tree bark extracts
(2019-08-01) Hamad A.; Ates S.; Olgun Ç.; Gür M.
Wood bark is a residue of forestry production that is used as a fuel source. The chemical composition of tree bark is similar to that of the harvested wood, and it contains a variety of useful compounds. To determine the chemical composition and antioxidant activities of different barks, fir (Abies nordmanniana), beech (Fagus orientalis), pine (Pinus sylvestris), poplar (Populus alba), and oak (Quercus robur) barks were selected because they are used for industrial purposes in Turkey. The dried bark powders were extracted using a 65:35 methanol-water mixture (v/v) to determine the total phenolic content, the flavonoid content, and the antioxidant properties (2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), metal chelating, and H2O2 scavenging). The flavonoid components were analyzed by high performance liquid chromatography (HPLC) and extracted by hexane to analyze the volatile components by gas chromatography-mass spectrometry (GC-MS). The poplar bark extracts had the highest total phenolic content, highest total flavonoid content, and highest antioxidant content. The poplar bark extracts were rich in myricetin (87.761 mg/L), which is a flavonoid with rich antioxidant properties. The presence of valuable extracts suggests that barks may have uses as valuable raw materials for chemical applications such as cosmetics, perfumes, and food preservatives.
Chemical contents and antifungal activity of some durable wood extractives vs. Pleurotus ostreatus
(2015-01-01) Ates S.; Gür M.; Özkan O.E.; Akça M.; Olgun Ç.; Güder A.
The total phenolic content (TPC), total flavonoid content (TFC), phenolic compounds, and antifungal activity of olive (Olea europaea var. sylvestris) and juniper (Juniperus foetidissima) sapwood and heartwood extractives were examined. The extractives were obtained using methanol solvents. The different compounds in extractives were identified and quantified. The antifungal activities of different parts of the olive and juniper wood extractives were determined in vitro. Pleurotus ostreatus mycelium was used for the antifungal activity experiment. Extractive compounds obtained from olive and juniper woods were found to be effective, natural antifungal agents.
DNA protection, antioxidant, antibacterial and enzyme inhibition activities of heartwood and sapwood extracts from juniper and olive woods
(2015-08-21) Özkan O.E.; Zengin G.; Akça M.; Baloʇlu M.C.; Olgun Ç.; Altuner E.M.; Ateş S.; Aktümsek A.; Vurdu H.
In this study, DNA protective, antioxidant, antibacterial and enzyme inhibiting properties of methanol extracts obtained from juniper and olive heartwood and sapwood were determined. These extracts were tested by five antioxidant methods (DPPH scavenging, FRAP, CUPRAC, metal chelating and phosphomolybdenum). Generally, heartwood extracts of both species are more efficient for DPPH radical scavenging activity, cupric ion reducing activity, ferric reducing antioxidant power and metal chelating activity than sapwood extracts. When compared to heartwood extracts, sapwood extracts have larger inhibition zone in disk diffusion test. In addition, all extracts showed high antibacterial activity against Staphylococcus aureus. DNA protection of both extracts had a capacity to inhibit the DNA damage arisen from Fenton's reagent. The highest DNA protective activity was observed in juniper sapwood extract with 84%. Furthermore, other extracts also indicated more than 60% of DNA protective activity. Olive wood extracts displayed the strongest enzyme inhibition activities against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Although juniper heartwood extracts showed highest anti-amylase, anti-glucosidase and anti-tyrosinase effects, they had no ability for inhibition BChE. The methanol extracts of olive samples demonstrated the most antioxidant activity (DPPH, CUPRAC and FRAP). In addition, juniper samples showed the highest anti-amylase, anti-tyrosinase, metal chelating and DNA protective activity. According to these results, the extracts of juniper and olive wood can be considered as a source of natural bio active agents for dietary, pharmacological and medicinal applications. This research will also serve as a base for future studies about biological activities of wood extracts.
Effect of pressing conditions on some surface properties of HDF laminate parquets
(2016-01-01) Kara M.; Yerlikaya Z.; Ateş S.; Olgun Ç.
In this study, the effects of lamination conditions on some commercialhigh density fiberboard(HDF) panels surface quality characteristics, surface strength, impact resistance test(large diameter ball test), curing degree, scratch resistance, abrasion resistance are investigated. For this purpose, HDF panels are produced from mixture wood fibers(50% black pine and 50% beech wood) as 8.3 mm thickness. After panels sanded to 7.3 mm thickness, laminated at different pressures and times. Ithas been found thathigh pressure and short-term press time conditionshave significant effect on surface strength, impact resistance, and abrasion resistance values. The best surface quality measurements are obtained from A1 group, pressure 340 kg/m² and 13 s pressing time(average of surface strength value of this group is 1.83 N/mm2, impact resistance value is 25.25 N and abrasion resistance value is 3650 revolution), but the lowest value is B3 groups, 320 kg/m² pressure and pressing time of 18 s(average of surface strength of this group is 1.58 N/mm2, impact resistance value is 20 N and abrasion resistance value is 3200 revolutions). Besides production factors of HDF panels and laminating material properties, press operating conditionshave been found to be decisive factors in laminate parquet pressing process for high surface quality.
Effects of Medium Density Fiberboards (MDF) Recycling Methods on Fiber Dimensions and Some Reconstructed Board Properties
(2023-01-01) Olgun Ç.; Ateş S.; Uzer E.
In this study, different methods, including acid hydrolysis (phosphoric and formic acid), thermohydrolysis, and microwave methods were tested for recycling of fiberboards made of 100 % beech and 70 % beech + 30 % pine wood fibers, which are widely sold in the market. The impacts of the using methods on the fibers were investigated with the help of a device that determines the fiber dimensions according to optical principles. In a laboratory setting, test boards were constructed using recycled fibers, and the changes in certain physical and mechanical qualities were studied. As a result, it was determined that recycled fibers obtained from microwave and thermo-hydrolysis fibers could be effectively used in fiberboard production. However, the proportion of fibers, longer than 1.24 mm, was decreased by about 30 % with the phosphoric acid method for MDF samples composed of 100 % beech fiber. The fiberboards could not be obtained from fibers recycled through acid hydrolysis except for phosphoric acid method with 100 % beech fibers.
Evaluation of some plastic wastes as an additive to reinforcing the high density fiberboard (Hdf)
(2021-01-01) Külçe T.; Ateş S.; Olgun Ç.
Using plastic wastes in the forest product industry as an additive material is an alternative solution method for decreasing environmental pollution. For this purpose, in this study; different types of plastic wastes, polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS), which have various characteristics and considerable potential as a reinforcing material for wood fibers, were added to the HDF boards on different mixture ratios (25/75, 50/50, 75/25) with already prepared commercial fibers. The changes on some board properties, like density, water absorption, thickness swelling, modulus of elasticity (MOE), bending strength (MOR), and internal bond strength of the produced high-density fiberboards (HDF) was determined. As a result, it was determined that water absorption and thickness swelling ratios of plastic waste added boards were lower than the control samples. Moreover, the mechanical properties of plastic waste used groups (except PET groups) were as nearly as control samples. According to the results, it is possible to easily say that, the PP and PS wastes can be evaluated in the reinforced HDF production process with different mixture ratios for different usage areas.