Phytochemical Characterization, Antioxidant, and Antimicrobial Activity of the Vegetative Buds from Romanian Spruce, Picea abies (L.) H. Karst.

This study aims to investigate the vegetative buds from Picea abies (spruce), naturally found in a central region of Romania, through a comprehensive analysis of the chemical composition to identify bioactive compounds responsible for pharmacological properties. Using HPLC/derivatization technique of GC-MS and quantitative spectrophotometric assays, the phenolic profile, and main components of an ethanolic extract from the buds were investigated. The essential oil was characterized by GC-MS. Moreover, the antioxidant activity with the DPPH method, and the antimicrobial activity were tested. Heavy metal detection was performed by graphite furnace atomic absorption spectrometry. The main components of the alcoholic extract were astragalin, quercetin, kaempferol, shikimic acid, and quinic acid. A total content of 25.32 ± 2.65 mg gallic acid equivalent per gram of dry plant (mg GAE/g DW) and of 10.54 ± 0.083 mg rutin equivalents/g of dry plant (mg RE/g DW) were found. The essential oil had D-limonene, α-cadinol, δ-cadinene, 13-epimanool, and δ-3-carene as predominant components. The spruce vegetative buds exhibited significant antioxidant activity (IC50 of 53 µg/mL) and antimicrobial effects against Staphylococcus aureus. Furthermore, concentrations of heavy metals Pb and Cd were below detection limits, suggesting that the material was free from potentially harmful contaminants. The results confirmed the potential of this indigenous species to be used as a source of compounds with pharmacological utilities.

Know When You Are Too Many: Density-Dependent Release of Pheromones During Host Colonisation by the European Spruce Bark Beetle, Ips typographus (L.).

Individuals across various animal species communicate their presence to conspecifics. Especially phytophagous and parasitoid insects with their brood developing on limited resources rely on chemical cues, such as host-marking pheromones, to reduce intraspecific competition. Bark beetles are phytophagous insects with some species being economically and ecologically relevant forest pests. Several of them use the volatile compound verbenone to inhibit attraction and reduce intraspecific competition. However, in the Eurasian spruce bark beetle, Ips typographus (L.), temporal emission patterns did so far not quite support the putative function of verbenone as an indicator of densely colonised host trees. More importantly, it is currently unclear how well verbenone emission is actually related to colonisation density and thus intraspecific competition. Here, we inoculated Norway spruce logs with I. typographus at two defined colonisation densities in the greenhouse and measured the emission of verbenone and its precursors α-pinene and verbenol over time. Verbenone emission was 3-7 times greater from colonised logs compared to decaying logs without beetles during the major part of larval development. Furthermore, our data supports the quantitative hypothesis, that the termination of attack on a tree is mediated by a cessation of the release of verbenol and continuous emission of verbenone. The latter is most likely a passively produced host-marking cue reflecting the actual density of conspecifics since per-beetle emission was unaffected by colonisation density. These findings shed new light on the regulation of bark beetle mass aggregations, which are currently causing previously unseen economic damages in temperate forests.

Biomonitoring of atmospheric PAHs using fir and spruce needles in forests in the vicinity of mountain villages.

The aim of the study was to use chemical analyses of spruce and fir needles to determine environmental exposure to polycyclic aromatic hydrocarbons (PAHs) in forests surrounding small mountain towns, including popular tourist destinations. The Beskid Mountains in Poland were chosen as the study area because they are very popular with tourists. The 6- and 12 month old needles were collected in two consecutive years from permanent study plots. Two vintages of needles were used to determine the differences between seasons in the profile of deposited pollutants. Some of plots were located away from roads and buildings, while others were located near tourist destinations. The comparison plots were located in the centre of a tourist resort, near a highway, and in a forest localised in the industrial city characterised by a high degree of urbanization. The analyses of 15 PAHs content showed that the amount and type of compounds retained by the needles were influenced not only by the proximity and amount of the surface emitters, but also by the location of the research sites above sea level. The results obtained can be explained, among other things, by the phenomenon of smog, which is not uncommon in the study region in autumn and winter.

Bioactive Molecules from Myrianthus arboreus, Acer rubrum, and Picea mariana Forest Resources.

Forest trees are the world's most important renewable natural resources in terms of their dominance among other biomasses and the diversity of molecules that they produce. Forest tree extractives include terpenes and polyphenols, widely recognized for their biological activity. These molecules are found in forest by-products, such as bark, buds, leaves, and knots, commonly ignored in forestry decisions. The present literature review focuses on in vitro experimental bioactivity from the phytochemicals of Myrianthus arboreus, Acer rubrum, and Picea mariana forest resources and by-products with potential for further nutraceutical, cosmeceutical, and pharmaceutical development. Although these forest extracts function as antioxidants in vitro and may act on signaling pathways involved in diabetes, psoriasis, inflammation, and skin aging, much still remains to be investigated before using them as therapeutic candidates, cosmetics, or functional foods. Traditional forest management systems focused on wood must evolve towards a holistic approach, allowing the use of these extractives for developing new value-added products.

Gymnosperms of Idaho: Chemical Compositions and Enantiomeric Distributions of Essential Oils of Abies lasiocarpa, Picea engelmannii, Pinus contorta, Pseudotsuga menziesii, and Thuja plicata.

Conifers are of great economic value in terms of lumber production, important for construction and other uses such as pulp and paper. They are also important sources of essential oils. Conifer species have been vital to the ethnobotany and traditional herbal medicine of many different Native American groups. The objective of this work was to obtain and analyze the essential oils of several conifer species (Abies lasiocarpa, Picea engelmannii, Pinus contorta, Pseudotsuga menziesii, and Thuja plicata) growing in Idaho. The foliar essential oils were obtained by hydrodistillation and then analyzed by gas chromatographic methods, including GC-MS, GC-FID, and chiral GC-MS. The essential oils were obtained in varying yields from 0.66% up to 4.70%. The essential oil compositions were largely dominated by monoterpene hydrocarbons and oxygenated monoterpenoids. The chiral monoterpenoids were generally rich in the (-)-enantiomers for members of the Pinaceae, but the (+)-enantiomers predominated in the Cupressaceae. The essential oil compositions obtained in this work are qualitatively similar, but quantitatively different, to previously reported compositions and confirm and complement the previous reports. However, this is the first comprehensive analysis of the chiral terpenoid components in these conifer species. Additional research on essential oils of the Pinaceae and Cupressaceae is needed to describe the chemical profiles, chemical compositions, and enantiomeric distributions more reliably in the various species and infraspecific taxa of these two families.

Conifer-killing bark beetles locate fungal symbionts by detecting volatile fungal metabolites of host tree resin monoterpenes.

Outbreaks of the Eurasian spruce bark beetle (Ips typographus) have decimated millions of hectares of conifer forests in Europe in recent years. The ability of these 4.0 to 5.5 mm long insects to kill mature trees over a short period has been sometimes ascribed to two main factors: (1) mass attacks on the host tree to overcome tree defenses and (2) the presence of fungal symbionts that support successful beetle development in the tree. While the role of pheromones in coordinating mass attacks has been well studied, the role of chemical communication in maintaining the fungal symbiosis is poorly understood. Previous evidence indicates that I. typographus can distinguish fungal symbionts of the genera Grosmannia, Endoconidiophora, and Ophiostoma by their de novo synthesized volatile compounds. Here, we hypothesize that the fungal symbionts of this bark beetle species metabolize spruce resin monoterpenes of the beetle's host tree, Norway spruce (Picea abies), and that the volatile products are used as cues by beetles for locating breeding sites with beneficial symbionts. We show that Grosmannia penicillata and other fungal symbionts alter the profile of spruce bark volatiles by converting the major monoterpenes into an attractive blend of oxygenated derivatives. Bornyl acetate was metabolized to camphor, and α- and ß-pinene to trans-4-thujanol and other oxygenated products. Electrophysiological measurements showed that I. typographus possesses dedicated olfactory sensory neurons for oxygenated metabolites. Both camphor and trans-4-thujanol attracted beetles at specific doses in walking olfactometer experiments, and the presence of symbiotic fungi enhanced attraction of females to pheromones. Another co-occurring nonbeneficial fungus (Trichoderma sp.) also produced oxygenated monoterpenes, but these were not attractive to I. typographus. Finally, we show that colonization of fungal symbionts on spruce bark diet stimulated beetles to make tunnels into the diet. Collectively, our study suggests that the blends of oxygenated metabolites of conifer monoterpenes produced by fungal symbionts are used by walking bark beetles as attractive or repellent cues to locate breeding or feeding sites containing beneficial microbial symbionts. The oxygenated metabolites may aid beetles in assessing the presence of the fungus, the defense status of the host tree and the density of conspecifics at potential feeding and breeding sites.

Odors Attracting the Long-Legged Predator Medetera signaticornis Loew to Ips typographus L. Infested Norway Spruce Trees.

Predatory long-legged flies of the genus Medetera are important, but currently understudied, natural enemies of Scolytinae bark beetles such as Ips typographus. Medetera flies lay eggs on beetle-infested trees, where the developing larvae find their prey, but the chemical cues used by Medetera to locate infested trees are currently unknown. To identify odors attracting Medetera signaticornis, a species in Europe, headspace samples were collected at several time-points through different stages of I. typographus attacks on logs of Norway spruce (Picea abies). The headspace samples were analyzed using combined gas chromatography and mass spectrometry (GC-MS), and gas chromatography coupled with electroantennographic detection (GC-EAD) to determine compounds that stimulate M. signaticornis antennae. Antennae of M. signaticornis males and females were found to detect (-)-cis-verbenol, ( +)-trans-verbenol and myrtenol, which are known to be produced by bark beetles. Antennal responses were also observed for verbenene, isoterpinolene, α-pinene oxide, camphor, pinocamphone, terpinene-4-ol, myrtenal, borneol, α-terpineol, geranyl acetone, and verbenone, which are primarily produced by microorganisms, and α-pinene, α-fenchene, ß-pinene, camphene, 3-carene, limonene, γ-terpinene, and terpinolene, known spruce tree compounds. In field experiments testing two synthetic blends containing 18 antennal active and two additional compounds 2-methyl-3-buten-2-ol and ipsdienol we observed significant attraction of M. signaticornis within 24 h. These attractive blends can form the basis for development of Medetera monitoring lures for use in future forest and pest management.

Fundamental Insights on the Physical and Chemical Properties of Organosolv Lignin from Norway Spruce Bark.

The interest in the bark and the attempt to add value to its utilization have increased over the last decade. By applying an integrated bark biorefinery approach, it is possible to investigate the recovery of compounds that can be used to develop green and sustainable alternatives to fossil-based materials. In this work, the focus is on extracting Norway spruce (Picea abies) bark lignin via organosolv extraction. Following the removal of the extractives and the subcritical water extraction to remove the polysaccharides, a novel cyclic organosolv extraction procedure was applied, which enabled the recovery of lignin with high quality and preserved structure. Main indicators for low degradation and preservation of the lignin structure were a high ß-O-4' content and low amounts of condensed structures. Furthermore, high purity and low polydispersity of the lignin were observed. Thus, the obtained lignin exhibits high potential for use in the direct development of polymer precursors and other bio-based materials. During the extraction sequence, around 70% of the bark was extracted. Besides the lignin, the extractives as well as pectic polysaccharides and hemicelluloses were recovered with only minor degradation, which could potentially be used for the production of biofuel or other high-value products such as emulsifiers or adhesives.

O2 as initiator of autocatalytic degradation of hemicelluloses and monosaccharides in hydrothermal treatment of spruce.

The influence of oxygen (0-50 bar) on the molar mass and composition of hemicelluloses after hydrothermal treatment of spruce chips was studied in a batch reactor setup at 130 °C-160 °C. Purified galactoglucomannan was studied as a reference. The dissolved oxygen enhanced significantly the depolymerization of hemicelluloses from over 15,000 g/mol to 180 g/mol (monomers) as well as promoted acids formation from the monosaccharides. About 2-3 times faster depolymerization was observed already with rather low amounts of oxygen (2-8 bar), while the kinetics of depolymerization was significantly slower in inert atmosphere. The decrease in pH from neutral to as low as 2.5 lead to an autocatalytic effect on the polysaccharide hydrolysis and the consecutive reactions of monosaccharides. The results emphasize the importance of performing hydrothermal treatment under inert atmosphere if large polymeric hemicellulsoses are desired or if monosaccharides are targeted in hydrolysis of hemicelluloses. If autocatalysis begins, it is difficult to stop.

Behaviour of Extractives in Norway Spruce (Picea abies) Bark during Pile Storage.

The current practices regarding the procurement chain of forest industry sidestreams, such as conifer bark, do not always lead to optimal conditions for preserving individual chemical compounds. This study investigates the standard way of storing bark in large piles in an open area. We mainly focus on the degradation of the most essential hydrophilic and hydrophobic extractives and carbohydrates. First, two large 450 m3 piles of bark from Norway spruce (Picea abies) were formed, one of which was covered with snow. The degradation of the bark extractives was monitored for 24 weeks. Samples were taken from the middle, side and top of the pile. Each sample was extracted at 120 °C with both n-hexane and water, and the extracts produced were then analysed chromatographically using gas chromatography with flame ionisation or mass selective detection and high-performance liquid chromatography. The carbohydrates were next analysed using acidic hydrolysis and acidic methanolysis, followed by chromatographic separation of the monosaccharides formed and their derivatives. The results showed that the most intensive degradation occurred during the first 4 weeks of storage. The levels of hydrophilic extractives were also found to decrease drastically (69% in normal pile and 73% in snow-covered pile) during storage, whereas the decrease in hydrophobic extractives was relatively stable (15% in normal pile and 8% in snow-covered pile). The top of the piles exhibited the most significant decrease in the total level of extractives (73% in normal and snow-covered pile), whereas the bark in the middle of the pile retained the highest amount of extractives (decreased by 51% in normal pile and 47% in snow-covered pile) after 24-week storage.

Molecular Characteristics and Antioxidant Activity of Spruce (Picea abies) Hemicelluloses Isolated by Catalytic Oxidative Delignification.

Spruce (Piceaabies) wood hemicelluloses have been obtained by the noncatalytic and catalytic oxidative delignification in the acetic acid-water-hydrogen peroxide medium in a processing time of 3-4 h and temperatures of 90-100 °C. In the catalytic process, the H2SO4, MnSO4, TiO2, and (NH4)6Mo7O24 catalysts have been used. A polysaccharide yield of up to 11.7 wt% has been found. The hemicellulose composition and structure have been studied by a complex of physicochemical methods, including gas and gel permeation chromatography, Fourier-transform infrared spectroscopy, and thermogravimetric analysis. The galactose:mannose:glucose:arabinose:xylose monomeric units in a ratio of 5:3:2:1:1 have been identified in the hemicelluloses by gas chromatography. Using gel permeation chromatography, the weight average molar mass Mw of hemicelluloses has been found to attain 47,654 g/mol in noncatalytic delignification and up to 42,793 g/mol in catalytic delignification. Based on the same technique, a method for determining the α and k parameters of the Mark-Kuhn-Houwink equation for hemicelluloses has been developed; it has been established that these parameters change between 0.33-1.01 and 1.57-472.17, respectively, depending on the catalyst concentration and process temperature and time. Moreover, the FTIR spectra of the hemicellulose samples contain all the bands characteristic of heteropolysaccharides, specifically, 1069 cm-1 (C-O-C and C-O-H), 1738 cm-1 (ester C=O), 1375 cm-1 (-C-CH3), 1243 cm-1 (-C-O-), etc. It has been determined by the thermogravimetric analysis that the hemicelluloses isolated from spruce wood are resistant to heating to temperatures of up to ~100 °C and, upon further heating, start destructing at an increasing rate. The antioxidant activity of the hemicelluloses has been examined using the compounds simulating the 2,2-diphenyl-2-picrylhydrazyl free radicals.

Compositional analysis of essential oil and solvent extracts of Norway spruce sprouts by ultrahigh-resolution mass spectrometry.

INTRODUCTION: Coniferous trees, especially their needles and bark, are a rich source of bioactive compounds. The developing needles of Norway spruce (Picea abies), also known as spruce sprouts, are enriched with vitamin C and other antioxidants, and thus they are used as a dietary supplement and have been traditionally used to treat various inflammatory disorders such as rheumatism and gout. Their chemical composition is only limitedly known, however. OBJECTIVES: The main objective of this work was to have a deeper understanding on the chemical composition of spruce sprouts to assess their full potential in different pharmaceutical, nutraceutical, or technochemical applications. MATERIALS AND METHODS: Ultrahigh-resolution Fourier-transform ion cyclotron (FT-ICR) mass spectrometry, coupled to direct-infusion electrospray ionisation (ESI) or atmospheric pressure photoionisation (APPI) techniques, was used for in-depth compositional analysis of solvent extracts and essential oil of spruce sprouts. RESULTS: A combined use of ESI and APPI techniques offered a great complementary insight into the rich chemistry of different spruce sprout extracts, allowing detection of thousands of chemical constituents with over 200 secondary metabolites tentatively identified. These compounds belonged to different classes such as organic acids, terpenes, flavonoids, stilbenes, sterols, and nitrogen alkaloids. CONCLUSION: Spruce sprouts have a complex metabolite profile that differs considerably from that of the old, developed needles.

Correlation between rheological measurements and morphological features of lignocellulosic micro/nanofibers from different softwood sources.

The transition of nanocellulose production from laboratory to industrial scale requires robust monitoring systems that keeps a quality control along the production chain. The present work aims at providing a deeper insight on the main factors affecting the rheological behavior of (ligno)cellulose micro/nanofibers (LCMNFs) and cellulose micro/nanofibers (CMNFs) and how they could correlate with their characteristics. To this end, 20 types of LCMNFs and CMNFs were produced combining mechanical refining and high-pressure homogenization from different raw materials. Aspect ratio and bending capacity of the fibrils played a key role on increasing the viscosity of the suspensions by instigating the formation of entangled structures. Surface charge, reflected by the cationic demand, played opposing effects on the viscosity by reducing the fibrils' contact due to repulsive forces. The suspensions also showed increasing shear-thinning behavior with fibrillation degree, which was attributed to increased surface charge and higher water retention capacity, enabling the fibrils to slide past each other more easily when subjected to flow conditions. The present work elucidates the existing relationships between LCMNF/CMNF properties and their rheological behavior, considering fibrillation intensity and the initial raw material characteristics, in view of the potential of rheological measurements as an industrial scalable characterization technology.

Spruce Bark-Extracted Lignin and Tannin-Based Bioresin-Adhesives: Effect of Curing Temperatures on the Thermal Properties of the Resins.

In this study, formaldehyde-free bioresin adhesives were synthesised from lignin and tannin, which were obtained from softwood bark. The extraction was done via organosolv treatment and hot water extraction, respectively. A non-volatile, non-toxic aldehyde, glyoxal, was used as a substitute for formaldehyde in order to modify the chemical structure of both the lignin and tannin. The glyoxal modification reaction was confirmed by ATR-FTIR spectroscopy. Three different resin formulations were prepared using modified lignin along with the modified tannin. The thermal properties of the modified lignin, tannin, and the bioresins were assessed by DSC and TGA. When the bioresins were cured at a high temperature (200 °C) by compression moulding, they exhibited higher thermal stability as well as an enhanced degree of cross-linking compared to the low temperature-cured bioresins. The thermal properties of the resins were strongly affected by the compositions of the resins as well as the curing temperatures.

Toxicological and bioactivity evaluation of blackcurrant press cake, sea buckthorn leaves and bark from Scots pine and Norway spruce extracts under a green integrated approach.

Aqueous extracts from blackcurrant press cake (BC), Norway spruce bark (NS), Scots pine bark (SP), and sea buckthorn leaves (SB) were obtained using maceration and pressurized hot water and tested for their bioactivities. Maceration provided the extraction of higher dry matter contents, including total phenolics (TPC), anthocyanins, and condensed tannins, which also impacted higher antioxidant activity. NS and SB extracts presented the highest mean values of TPC and antioxidant activity. Individually, NS extract presented high contents of proanthocyanidins, resveratrol, and some phenolic acids. In contrast, SB contained a high concentration of ellagitannins, ellagic acid, and quercetin, explaining the antioxidant activity and antibacterial effects. SP and BC extracts had the lowest TPC and antioxidant activity. However, BC had strong antiviral efficacy, whereas SP can be considered a potential ingredient to inhibit α-amylase. Except for BC, the other extracts decreased reactive oxygen species (ROS) generation in HCT8 and A549 cells. Extracts did not inhibit the production of TNF-alpha in lipopolysaccharide-stimulated THP-1 macrophages but inhibited the ROS generation during the THP-1 cell respiratory burst. The recovery of antioxidant compounds from these by-products is incentivized for high value-added applications.

Declining carbohydrate content of Sitka-spruce treesdying from seawater exposure.

Increasing sea levels associated with climate change threaten the survival of coastal forests, yet the mechanisms by which seawater exposure causes tree death remain poorly understood. Despite the potentially crucial role of nonstructural carbohydrate (NSC) reserves in tree survival, their dynamics in the process of death under seawater exposure are unknown. Here we monitored progressive tree mortality and associated NSC storage in Sitka-spruce (Picea sitchensis) trees dying under ecosystem-scale increases in seawater exposure in western Washington, USA. All trees exposed to seawater, because of monthly tidal intrusion, experienced declining crown foliage during the sampling period, and individuals with a lower percentage of live foliated crown (PLFC) died faster. Tree PLFC was strongly correlated with subsurface salinity and needle ion contents. Total NSC concentrations in trees declined remarkably with crown decline, and reached extremely low levels at tree death (2.4% and 1.6% in leaves and branches, respectively, and 0.4% in stems and roots). Starch in all tissues was almost completely consumed, while sugars remained at a homeostatic level in foliage. The decreasing NSC with closer proximity to death and near zero starch at death are evidences that carbon starvation occurred during Sitka-spruce mortality during seawater exposure. Our results highlight the importance of carbon storage as an indicator of tree mortality risks under seawater exposure.

Dynamics of Isomeric and Enantiomeric Fractions of Pinene in Essential Oil of Picea abies Annual Needles during Growing Season.

Norway spruce (Picea abies (L.) H. Karst.) is one of the most important commercial tree species distributed naturally in the Boreal and subalpine forest zone of Europe. All parts of spruce trees, including needles, accumulate essential oils with a variety of chemical properties and ecological functions, such as modulating plant-insect communication. Annual needle samples from 15 trees (five from each of three habitats) of 15-17 years old were assayed for essential oils and their major compounds, including α-pinene, ß-pinene, (1S)-(-)-α-pinene, and (1R)-(+)-α-pinene across a growing season. Results showed strong positive correlation between percentages of α- and ß-pinene isomers (r = 0.69, p < 0.05) and between pinene isomers and essential oils: α-pinene correlated with essential oil stronger (r = 0.62, p < 0.05) than ß-pinene (r = 0.33, p < 0.05). Correlation analyses performed with some weather conditions, including average monthly temperature, growing sum of effective temperatures over 5 °C, duration of sunshine, accumulated precipitation, relative humidity, and pressure, showed that temperature is the most important weather condition related to pinene dynamics: negative correlations of moderate strength were established between percentages of α- and ß- pinenes and average monthly temperatures (r = -0.36, p < 0.01, n = 75 and r = -0.33, p < 0.01, n = 75, respectively). Out of pinene enantiomers, only (1S)-(-)-α-pinene showed some negative correlation with monthly temperature (r = -0.26, p < 0.05, n = 75). Different patterns of essential oil and pinene dynamics during growing season within separate habitats suggested that some genetic variables of Picea abies might be involved.

Stability and Photoisomerization of Stilbenes Isolated from the Bark of Norway Spruce Roots.

Stilbenes or stilbenoids, major polyphenolic compounds of the bark of Norway spruce (Picea abies L. Karst), have potential future applications as drugs, preservatives and other functional ingredients due to their antioxidative, antibacterial and antifungal properties. Stilbenes are photosensitive and UV and fluorescent light induce trans to cis isomerisation via intramolecular cyclization. So far, the characterizations of possible new compounds derived from trans-stilbenes under UV light exposure have been mainly tentative based only on UV or MS spectra without utilizing more detailed structural spectroscopy techniques such as NMR. The objective of this work was to study the stability of biologically interesting and readily available stilbenes such as astringin and isorhapontin and their aglucones piceatannol and isorhapontigenin, which have not been studied previously. The effects of fluorescent and UV light and storage on the stability of trans stilbenes were assessed and the identification and characterisation of new compounds formed during our experiments were carried out by chromatographic (HPLC, GC) and spectroscopic techniques (UV, MS, NMR). The stilbenes undergo a trans to cis isomerisation under extended UV irradiation by intramolecular cyclisation (by the formation of a new C-C bond and the loss of two hydrogens) to phenanthrene structures. The characterised compounds are novel and not described previously.

Differentiation of Honeydew Honeys from Blossom Honeys and According to Their Botanical Origin by Electrical Conductivity and Phenolic and Sugar Spectra.

Honeydew honey, due to its higher antibacterial and antioxidant activity in comparison to blossom honeys, is in high demand and of interest to consumers. Although a differentiation of blossom honeys from honeydew honeys by way of electrical conductivity is given in many cases, criteria for a differentiation of individual honeydew honeys, such as spruce, fir, and pine, however did not exist. For this reason, 93 authentic honeydew honeys and 63 non-honeydew honeys [35 blossom and 28 nectar-honeydew (mixed)] from 13 different botanical origins were collected within the framework of the current study, and their electrical conductivity and phenolic and sugar profiles were investigated. Results showed that the higher electrical conductivity (≥0.80 mS/cm), the higher protocatechuic acid content (≥3.5 mg/kg), and the higher percentage of the oligosaccharide content (≥120 mg/g) were suitable parameters for the differentiation of authentic coniferous honeydew honeys from non-honeydew honeys; a differentiation. A differentiation of the spruce, fir, and pine honeydew honeys however could not be reached. Through the analysis of 32 carbohydrates (2 mono-, 7 di-, 10 tri-, and 13 higher oligosaccharides) in only one run by high-performance liquid chromatography equipped with an evaporative light scattering detector, marker substances can now be utilized for the classification of individual honeydew honeys. Sugar marker compounds such as α,α-trehalose, melezitose, theanderose, nystose, or maltotetraose in honeydew honeys in combination with chemometrics highlighted the good capability of sugar profiles to discriminate the honeydew honeys both from the non-honeydew honeys and from each other. All in all, a 96.75% correct classification of all studied 156 honey samples was achieved by sugar marker compounds.

Disassociated molecular orientation distributions of a composite cellulose-lignin carbon fiber precursor: A study by rotor synchronized NMR spectroscopy and X-ray scattering.

Cellulose-lignin composite carbon fibers have shown to be a potential environmentally benign alternative to the traditional polyacrylonitrile precursor. With the associated cost reduction, cellulose-lignin carbon fibers are an attractive light-weight material for, e.g. wind power and automobile manufacturing. The carbon fiber tenacity, tensile modulus and creep resistance is in part determined by the carbon content and the molecular orientation distribution of the precursor. This work disassociates the molecular orientation of different components in cellulose-lignin composite fibers using rotor-synchronized solid-state nuclear magnetic resonance spectroscopy and X-ray scattering. Our results show that lignin is completely disordered, in a mechanically stretched cellulose-lignin composite fiber, while the cellulose is ordered. In contrast, the native spruce wood raw material displays both oriented lignin and cellulose. The current processes for fabricating a cellulose-lignin composite fiber cannot regain the oriented lignin as observed from the native wood.