Larch Bark Research Articles

Research on Anticorrosive Effects of Larch Bark Extract with Addition of Collagen

The results of the study of the anticorrosive protective effects of the larch bark extract with addition of collagen have been given in this article. It was found that the best way of water extraction of tannins from larch bark is a temperature of 60 ° C during 1 hour, since at high temperatures, partial destruction of tannins occurs, and with an increase in the extraction time of more than an hour, the process of adsorption of these substances by the bark takes place. The corrosion rate was determined by the intensity of the blue colour of the complex compound of iron (II) cations - the truncul blue Fe3[Fe (CN)6]2 on a photocolorimeter with a yellow light filter at a wavelength of 590 nm. The average corrosion rate was calculated by the concentration of the resulting Fe2+ cations (within 1 minute). Based on the average corrosion rates, the protective effect of the extract (Z) and the drag coefficient (γ) were determined. It has been identified that the protective effect of the larch bark extract is equal to 37.5%, while addition of collagen leads to 2.3 time increase of protective effects of the extract. This can be explained by the fact that, with collagen additive, good adhesion of tannins to the surface of iron occurs resulting from formation of complex compounds, and a protective collagen film is formed, preventing an access of oxidizing agents to the metal surface.

Физико-химические показатели коры лиственницы сибирской: натуральной, химически модифицированной и после адсорбции катионов тяжелых металлов

Физико-химические показатели коры лиственницы сибирской: натуральной, химически модифицированной и после адсорбции катионов тяжелых металлов

Qualitative investigation on VOC-emissions from spruce (Picea abies) and larch (Larix decidua) loose bark and bark panels

Tree bark is an interesting source for various building and furniture materials. It holds a high number of volatile components—resulting in emissions whose effects on building residents have to be considered. Spruce and larch barks were dried using different methods and prepared as loose particles and panels. The VOC (volatile organic compound) emissions after 3 and 14 days were measured in a small chamber using gas chromatography and coupled mass spectroscopy. The influence of bark type, drying method, hot pressing and time on the emissions was quantified. The total volatile organic compounds (TVOC) emissions from spruce bark were higher than those from larch bark. High-temperature treatment and time significantly decrease TVOC emissions from the investigated barks. Terpenes, aldehydes and acids were analysed in the emitting gases. The high temperatures whilst pressing panels are problematic due to furfural constitution. Its emissions and partly those of 2-octenal and acetic acid are relevant for present and upcoming evaluation schemes. Aldehydes are the critical substance when using bark in the interior and must be controlled in product development.

Ophiostomatoid fungi associated with Ips subelongatus, including eight new species from northeastern China

Ips subelongatus is a major pest that infects larch plantations over large areas of northern and northeastern China. Ips species are closely associated with ophiostomatoid fungi that are morphologically well-adapted for dispersal by beetles. These associations result in important threat for coniferous forests worldwide. The aim of this study was to characterize the ophiostomatoid communities associated with I. subelongatus infesting Larix species and sympatric Pinus sylvestris var. mongolica in northeastern China forests. Morphological and multilocus phylogenetic approaches (based on six markers: ITS, LSU, 60S, β-tubulin, EF-1α, and CAL gene regions) allowed identifying 14 species of four genera (Ceratocystiopsis, Endoconidiophora, Leptographium and Ophiostoma). Eight species are showed to be new to science. Most strains resided in two Ophiostoma species complexes, viz. the O. clavatum and the O. ips complexes, all together accounting for 76.8% of all isolates. Ophiostoma hongxingense sp. nov., O. peniculi sp. nov., and O. subelongati sp. nov. (O. clavatum complex) and O. pseudobicolor sp. nov. (O. ips complex) were the four dominant species. The ophiostomatoid communities associated with larch bark beetles, I. cembrae and I. subelongatus, in Europe and Asia, China and Japan, also were compared. These comparisons showed distinct, specific assemblage patterns.

Analysis of Larch-Bark Capacity for Formaldehyde Removal in Wood Adhesives.

Ecofriendly wood-based materials are required by consumers at present. Decorative panels are part of a large group of wood-composite materials, and their environmental properties must not be neglected. More environmentally friendly decorative panels can be achieved by various methods. This paper describes a method of production from larch bark. Tree bark, as a byproduct of the wood industry, is one of the research topics that have gained interest in the last decade, especially for its applications in biobased lignocomposites, with regard to the shrinkage of wood resources. In the present work, the formaldehyde content of decorative boards based on larch bark (0.6 g/cm3) was analyzed when bonded with five different types of adhesive systems: urea-formaldehyde, polyvinyl acetate, the mixture of 70% urea-formaldehyde + 30% polyvinyl acetate, polyurethane, and tannin-based adhesive. A self-agglomerated board was also analyzed. The formaldehyde content of the larch-bark samples was determined with the perforator method (EN 120:2011), and findings showed that all tested samples reached the E1 classification (≤8 mg/100 oven dry). Moreover, 75% of the values of the corrected formaldehyde content were included in the super-E0 class (≤1.5 mg/100 oven dry). In the case of boards bonded with tannin-based adhesive, this natural polymer acted as a formaldehyde scavenger.

Organic matter mineralization of larch bark and compositions based on it

The process of organic matter mineralization in fertilizer mixtures consisting of larch bark and mineral additives was studied in order to optimize the timing of composting and preparation of high-quality fertilizers. The main factors affecting the process of bark mineralization are the reaction of the medium (pH), the ratio of C:N, mineral additives. The process of larch bark mineralization and compositions based on it is described by the equation of the first order. The calculated decomposition constants of fertilizer compositions exceeded the control by 2-3, 2 times depending on the variant of the experiment.

Influence Exerted by Cross-Linking Effect on Properties of Sorbents Produced from Aspen and Larch Bark

Method is suggested for obtaining biochar materials by treatment of a finely dispersed (≤0.1 mm) bark of aspen and(or) larch with a 40% formaldehyde solution and subsequent thermal activation of the activated bark. It was found that keeping the composite at a temperature of 50–80°C for three days makes the binding process complete. Further carbonization at temperatures of 350–900°C yields a biochar with bulk structure. The method of IR spectroscopy confirmed that the functional composition of bark changes under the action of a cross-linking agent and — CH2 — bonds are additionally formed. It was found that the larch bark containing lignins of predominantly G-type and condensed tannins is more suitable for obtaining porous biochar materials (with specific surface area of 94–161 m2 g−1) as compared with the aspen bark. The adsorption properties of biochar materials produced from the modified bark in removal of Cu(II) ions from aqueous solutions. It was found that, on being carbonized at 900°C, a sample of modified aspen bark can extract 122.9 to 220 mg g−1 of copper compounds on raising the sorption temperature from 25 to 45°C.

Low-Cost Ru/C-Catalyzed Depolymerization of the Polymeric Proanthocyanidin-Rich Fraction from Bark To Produce Oligomeric Proanthocyanidins with Antioxidant Activity.

A new method has been developed for the high-value utilization of larch bark, which is regarded as a low-value byproduct of the logging industry. Polymeric proanthocyanidins (PPCs) were extracted from the Larix gmelinii bark and depolymerized by catalytic hydrogenolysis, using ruthenium/carbon (Ru/C) as the catalyst. The method has been found that although the molecular weight of the depolymerized product was significantly lower, the basic structural units were not destroyed, and the product retained a condensed flavanol polyphenol structure; the depolymerized product contains very little Ru metal and thus complies with food safety standards; the antioxidant properties of both the depolymerized products and PPCs were better than those of the commonly used antioxidant 2,6-di-tert-butyl-4-methylphenol. The relative molecular weight and steric hindrance of the depolymerized products were lower than those of the PPCs, leading to better antioxidant performance. A new technical route for the depolymerization of PPCs from the L. gmelinii bark is provided. The route offers practical and commercial advantages, and the product could have many applications as an antioxidant.

Relationship between the composition and distribution of nutritional substances, secondary metabolites, and internal secretory structures in the bark tissues of Larix gmelinii var. japonica, L. kaempferi, and their F1 hybrid and susceptibility to vole herbivory

ABSTRACTWe investigated the quantitative composition and distribution of nutritional substances (soluble sugars, starch, and protein), secondary metabolites (terpenoids and phenolic compounds), and the length, area, and density of internal secretory structures (resin ducts and cavities) in the rhytidome (outer bark) and secondary phloem (inner bark) of Kuril larch (Larix gmelinii var. japonica), Japanese larch (L. kaempferi), and their F1 hybrid (L. gmelinii var. japonica × L. kaempferi) in order to clarify the relationship of these parameters to susceptibility to red-backed voles’ herbivory in Hokkaido, Japan. The amounts of most nutritional substances in each of both bark tissues were not significantly different among the three larch taxa. The amounts of carane-type monoterpenoid and labdane-type diterpenoid in both bark tissues of L. gmelinii var. japonica and the F1 hybrid were significantly higher than those of L. kaempferi. The amounts of phenolic compounds in both bark tissues of L. gmelinii var. japonica were significantly lower than those of L. kaempferi. The quantitative composition of most secondary metabolites in both bark tissues of the the F1 hybrid were between L. gmelinii var. japonica and L. kaempferi. The area and density of the resin ducts and cavities, which were containing terpenoids, in both bark tissues of L. gmelinii var. japonica and the F1 hybrid were significantly larger and higher than those of L. kaempferi. These results suggest that L. gmelinii var. japonica and the F1 hybrid utilize some predominant constitutive mono- and diterpenoids as chemical defensive substances in the bark tissues against the voles.

Anti-corrosion action of the extract of the larix sibiric barrus with different methods applying on the surface of metal

This article provides a method of the larch bark extract applying on a metal surface and also determining its anticorrosive protective action. It has been established that the protective effect of the larch bark extract was 37.5%, and when applying the extract after phosphoric acid, the protective effect increases to 65%, since the formed iron phosphates, having a porous structure, are a good primer and increase the adhesion of the rust converter. The sequence of the solutions application was determined: firstly, phosphoric acid and only after that the extract of larch bark. This sequence of components application leads to an improvement of the anticorrosion characteristics of the studied extract: at the same time, the protective effect of the extract Z and the inhibiting factor of corrosion γ increase 1.7-1.8 times.

Identification of antimicrobial compounds in different hydrophilic larch bark extracts

Larch bark is an undervalued material, but it has unique and valuable characteristics and compounds. The objective of this study was to extract and characterize molecular compounds of bark materials from different larch trees and to test these for their antimicrobial properties. The extractions were performed using methanol or water. The obtained extracts were analysed by gas chromatography coupled to mass spectrometry (GC-MS). Antimicrobial properties also were determined using different microbial strains, for example, Staphylococcus aureus. The GC-MS analysis showed that long chain alcohols, fatty acids, and polyphenols were present in the extracts. According to the results of the agar diffusion tests, only the methanol extract of larch bark had an inhibitory effect on the growth of Staphylococcus aureus. Two compounds of flavonoids and stilbenoids were shown to affect the microbial activity of the larch bark. Therefore, larch bark can be used for the extraction of compounds with specific anti-microbial properties.

Investigation of the Sorbing Properties of the Dahurian Larch Bark in its Interaction with Petroleum Products

As is known, pollution of the environment by oil products leads to the gravest consequences, the elimination of which is expencive for mankind. Thereby intensive researches of effective methods of liquidation of oil pollution are conducted now. Sorbents on a plant basis favorably differ by their ecological compatibility, availability and cheap material. In the present work, the problems of the development of a sorbent on the basis of modification of the bark of Dahurian larch, which grows mainly in Eastern Siberia and the Far East, in particular in the Republic of Sakha (Yakutia) are considered. The results of experimental measurements of the sorption capacity of the modified bark of the Daurian larch are presented.

Induced antimicrobial activity in heat‐treated woodchips inhibits the activity of the invasive plant pathogen Phytophthora ramorum

The antimicrobial activity of heat‐treated woodchips of three woody host species against the invasive oomycete plant pathogen Phytophthora ramorum was investigated to assess the potential of heated woodchips to suppress disease. Results demonstrated that heat‐treated woodchips of pine (Pinus sylvestris), Japanese larch (Larix kaempferi) and rhododendron (Rhododendron ponticum) inhibited recovery of P. ramorum spores and mycelium compared with similar material that had only been air‐dried. Effects were most evident with pine and larch; inhibition was maintained even when larch woodchips were diluted with soil. In vitro assays using methanol crude extracts from woodchips of the three species showed they all had an inhibitory effect on P. ramorum zoospores and reduced chlamydospore germination compared with air‐dried wood extracts. Chemical analysis of the extracts revealed several induced compounds were present but in different concentrations for each species. Coniferaldehyde was the most active inhibitor against spores and mycelium, while the dominant resin acids, dehydroabietic and abietic acid, decreased the minimum inhibitory concentration of phenolic compounds tested against P. ramorum but were ineffective when used alone. An array of compounds, including dehydroabietic acid, methyl abietate, α‐pinene and 3‐carene, occurred at elevated levels in the living tissue of Japanese larch bark attacked by P. ramorum. These compounds may be part of the induced resistance response of larch to P. ramorum. Results of a field trial using heat‐treated and air‐dried woodchips were consistent with the crude extract bioassay results, suggesting that heat‐treated woody materials have potential to reduce the survival of P. ramorum under natural conditions.

THE POSSIBILITY OF USING PECTIN OF CONIFEROUS TREES AS STRUCTURE-FORMING

In recent years, the demand for food has sharply increased in functional ingredients, especially in pectin. At present, there is no production of pectin substances in the Russian Federation, and the demand for them is satisfied, mainly due to the use of imported pectin. At the same time, the country has prerequisites for its own production of pectin from non-traditional types of raw materials, for example, bark of coniferous trees, which in the form of waste is produced in large quantities when processing wood in the timber, woodworking and pulp and paper industries, and goes to incineration, although its can be used to obtain such a valuable substance as pectin. The article considers the possibility of using pectins from the bark of coniferous trees in the production of fruit and vegetable nectars with pulp as a biological additive that improves the consistency of the product. To confirm this, VNII researchers of conservation technology conducted studies to test pectin from the bark of spruce and larch on their structure-forming ability. For this purpose, experimental samples of fruit and vegetable nectars with pulp were made: apricot, quince, cherry, redcod, plum and carrot, obtained on the basis of fruit and vegetable purees, as well as the calculated amount of sugar syrup with a certain concentration, with the addition of pectin from the spruce bark and larch, and for comparison samples with the addition of ordinary apple pectin. Pectin was added as a 10% solution in an amount of 9.0% of the total weight of nectar (in terms of dry pectin – 0.9%), which allowed to provide a homogeneous, non-dissolving consistency of nectars.

Polyphenols of Wood Bark: Organic Precursors for the Production of Polymer Aerogels

A new method for preparation of organic aerogels by sol–gel polymerization of formaldehyde with polyphenols (PPs), isolated from larch bark and birch bark, was developed. The functional composition and properties of the original polyphenols were studied by thermogravimetric methods and FTIR spectroscopy. It was found that larch polyphenol material had higher thermal stability in the temperature range 25−700°C, while the process of thermal decomposition of birch bark polyphenols completes at 600°C. It has been established that polyphenol larch compounds contain more aromatic structures and hydroxyl groups. The effect of the pH of gelation solutions in the range from 4 to 12 on the porous structure of organic gels synthesized from polyphenols was studied. The porous structures and adsorption properties of polyphenol-formaldehyde organic gels were studied using the BET method, scanning electron microscopy and sorption (methylene blue and gelatin). It was shown that an increase in pH contributes to the formation of a product with a more compacted texture. The electron microscopic images of polymer gels demonstrate a uniform granular texture with visible microglobules with an average particle size of ≈50−70 nm.

Reaction mechanism and evolved gases of larch bark pyrolysis by TG-FTIR analysis

The reaction mechanism and evolved gases of larch bark were investigated using thermogravimetry and Fourier transform infrared spectrometry analysis at 10–50 K min−1. Larch bark pyrolysis starts at approximately 450 K. One peak and one shoulder at low heating rate were observed. This shoulder turns into another peak at higher heating rate. The average value of the final residue is approximately 24%. The average activation energy was estimated as 184.72 kJ mol−1 by the Flynn–Wall–Ozawa method and 201.24 kJ mol−1 by the Kissinger–Akahira–Sunose method, and both have a discrepancy of 8.9%. The sixth or seventh reaction model is responsible for larch bark pyrolysis. The pyrolysis of larch bark produces H2O, CO2, CH4, CO, C=O and others, most of which are released in the temperature range of 500–800 K, except that CO2 has an additional peak value at around 1200 K. In addition, cellulose is the main component in larch bark, and its quantity is larger than that of hemicellulose.

Preparation and Characterization of Antioxidative and UV-Protective Larch Bark Tannin/PVA Composite Membranes.

In order to prepare functional materials for antioxidant and ultraviolet (UV)-protective green food packaging, condensed tannin, previously extracted from larch bark, was mixed with polyvinyl alcohol (PVA), and then the mixture was used to cast composite membranes. An antioxidative assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH)—a free radical scavenger—and starch–potassium iodide oxidation–discoloration analyses showed that the composite membranes have good antioxidative activities. The low UV transmission and protective effect of the composite films on vitamin E indicated the UV protection ability of the composite membranes. Both larch bark tannin and PVA are rich in hydroxyl groups; scanning electron microscopy analysis demonstrated their compatibility. Also, the mechanical and crystallization properties of the composite membranes did not significantly decrease with the addition of larch bark tannin.

Water vapour diffusion resistance of larch (Larix decidua) bark insulation panels and application considerations based on numeric modelling

This paper focuses on the vapour diffusion resistance of light particleboard produced from larch (Larix decidua) bark for thermal insulation applications. The influence of panel density and particle orientation, as well as particle size was evaluated in this respect. The former proved to have the most important effect. The panels' structure was illuminated by means of computed tomography and used as an input for a structure-based numeric model for vapour diffusion. The model was found to be suitable to describe the mass flow in the panels and was used to propose some optimisation of panel structure to serve for special needs in building engineering.

Использование пектинов из коры хвойных пород деревьев при производстве консервированной продукции

The article deals with the possibility of utilization of pectins from the bark of coniferous tree species for the manufacture of fruit and vegetable canned goods (jelly, jam and nectars with pulp) as biological additives that improve product consistency. Due to their unique properties, pectin substances are widely used in modern conditions and can be used as an additive in the production of food products. In the food industry, of particular importance are such properties of pectin substances as gelling, structure-forming and thickening abilities, which is very important when creating food products with certain structural characteristics. Experimental samples of fruit jams with the introduction of different amounts of pectin to thicken the product (0.3%, 0.5%, 0.8%, 1.0%) were put out. During the sensor analysis of these jams the best characteristics were obtained by samples, into which pectin from the bark of spruce in an amount of 1.0% was added. The possibility of using pectins from the bark of spruce and larch as gelling agents in the manufacture of jelly was investigated. Composite mixtures which produced three versions of the jelly images with pectin were developed: No.1 - control with apple pectin; No. 2 - with pectin from the spruce bark; No. 3 - with pectin from the larch bark. It has been established that the organoleptic characteristics of the sample No.2 differ from the control sample slightly. Sample No. 3 has received non-satisfactory rating in all organoleptic parameters. To confirm the structure-forming ability of pectin from spruce bark, the samples of nectars with pulp with addition of pectin from spruce bark are manufactured. The expediency of using this pectin is 0.9%.

Antimicrobial activity and mechanism of Larch bark procyanidins against Staphylococcus aureus.

Larch bark procyanidins (LBPCs) have not only antioxidant and antitumor properties, but also strong bacteriostatic effects. However, it is not clear about the antibacterial mechanisms of LBPC. In this work, the antibacterial effects and mechanisms of LBPC on Staphylococcus aureus were studied in the aspects of morphological structure, cell wall and membrane, essential proteins, and genetic material. The results showed that LBPC effectively inhibited bacterial growth at a minimum inhibitory concentration of 1.75 mg/ml. Bacterial morphology was significantly altered by LBPC treatment, with the cell walls and membranes being destroyed. Extracellular alkaline phosphatase content, bacterial fluid conductivity, and Na+/K+-ATPase and Ca2+-ATPase activities in the membrane system were all increased. In the energy metabolic systems, the activities of succinate dehydrogenase, malate dehydrogenase, and adenosine triphosphatase (ATPase) were all decreased, resulting in a slowdown of metabolism and bacterial growth inhibition. Changes of protein content and composition in the bacteria suggested that the protein expression system was affected. In addition, LBPC was found to bind to DNA grooves to form complexes. Thus, LBPC has a very strong inhibitory effect on S. aureus and can kill S. aureus by destroying the integrity and permeability of the cell wall and cell membrane, affecting protein synthesis, and binding to DNA.