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.

This work investigated some mechanical, physical and free formaldehyde emission properties of heat-treated MDF. For this purpose, MDF panels were subjected to varying heat treatment temperatures (155°C, 165°C and 175°C), durations (2.5 h., 3.5 h. and 4.5 h.) and waiting times after hot pressing (30 min., 120 min. and 600 min). Thickness swelling (TS), water absorption (WA), free formaldehyde emission (FFE), bending strength (BS), modulus of elasticity (MOE), tensile strength perpendicular to fibers (TSPF) for treated and untreated samples were tested and evaluated statistically. Consequently, after the heat treatment values of tensile strength, bending strength and modulus of elasticity were almost negatively affected relatively, but the thickness swelling and water absorption and quantities of free formaldehyde were improved positively of MDF samples.

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.

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.

Odun çok önemli bir doğal kaynaktır ve dünyadaki yenilenebilir kaynaklardan olan selüloz, selülozik olmayan polisakkaritler (hemiselüloz ve pektin) ve lignini içeren heterojen doğal bir malzemedir. Selüloz, suyla birleştiği zaman özgün fiziksel ve kimyasal özelliklerinden dolayı uygun bir gıda katkı maddesi olmaktadır. Selüloz ve fiziksel ve kimyasal türevleri gıda imalatında uzun yıllardır kullanılmaktadır. Fiziksel olarak modifiye edilmiş selüloz, düşük kalorili yiyecekler, alkollü içeceklerde tatlandırıcı yada yapay tatlandırıcılar gibi toptan gıda özelliklerinin arzulandığı pek çok üründe kullanışlı olmaktadır. Ayrıca selüloz hem yoğunlaştırma hem de emülsiyon reaksiyonlarına katılmaktadır. Gıdalardaki selüloz türevleri reolojik özelliklerin düzenlenmesinde, emülsiyonlaştırma, köpük stabilizasyonu, buz kristallerinin modifikasyonu ve su bağlama kapasitesinde kullanılmaktadır.

Aim of study: In this study, it was aimed to research the anatomical properties, chemical composition of the cell wall and fiber characteristics of Turkish Red Pine (Pinus brutia Ten.) wood sampled from five different zone of Kastamonu province in Turkey. Area of study: This study was performed at the laboratories of Department of Forest Industry Engineering and Department of Biology, Kastamonu University. Material and Methods: Turkish Red Pine (Pinus brutia Ten.) wood samples obtained from Hanonu, Bozkurt, Arac, Inebolu and Tosya were used as experimental materials. Anatomical properties, chemical structure of wood and fibrous characteristics of wood fibers were determined according to standard methods. Main results: This study indicated that Tosya samples had maximum fibre length with 3.15 mm and maximum lumen width with 27.75. m, whereas maximum fibre width was found in Inebolu samples with 42.27. m and maximum cell wall thickness was seen in samples of Inebolu with 7.90. m. As a consequence of chemical analyses, it was confirmed that holocellulose, alpha-cellulose and lignin ratios, 1% NaOH, ethanol, hot water and cold water solubilities and ash ratio changed within the range of 70.37-72.38, 42.62-47.30, 26.04-27.86, 12.38-13.14, 2.38-3.41, 2.86-3.83, 2.29-3.27 and 0.26-0.40 as percent respectively. In the results of anatomical research, it was seen that Hanonu samples had maximum average ray numbers with 7. Likewise, maximum tracheid widths were found samples in Inebolu and Bozkurt with 1.31 mu m. Besides, maximum earlywood width was confirmed Bozkurt samples with 0.47 mm, whereas maximum latewood width was confirmed Hanonu samples with 1.31 mm. Research highlights: It is inferred that the same tree species taken from different areas have varied anatomical, chemical and fibre properties measured by means of this study. Because of this, it can be stated that growth location properties and growth media affect the characteristics of same type trees.