Low Molecular Phenolics Research Articles

Directional and integrated conversion of whole components in biomass for levulinates and phenolics with biphasic system

Integrated conversion and stepwise extraction of whole components in biomass with biphasic system are introduced for producing chemicals: levulinates and phenolics. When methanol/dimethoxymethane as biphasic solvent, 46.51% methyl levulinate and 18.78% phenolics were obtained with a conversion of 80.59 wt% per 4 g rice straw under the mild reaction conditions. Levulinates were collected with a 87.5 wt% high purity of methyl levulinate with stepwise precipitation and extraction from the cellulose and hemicellulose. The results of acid value, freezing point, induction period, kinematic viscosity, and flash point supposed that the extracted methyl levulinate could meet the requirements of fuel additives. Depolymerized lignin was consisted of many low-molecular phenolics. These results illustrated that the biphasic system can promote the conversion of cellulose and hemicellulose to the same product methyl levulinate through different intermediate transition compounds, and the catalyst can contribute to directly cleave the glycosidic bonds, β-O-4, and 4-O-5 with adequate protons.

ELABORATION OF THE NEW METHOD OF CONSERVING VOLATILE AROMATIC SUBSTANCES OF SPICY VEGETABLES AT CREATING HEALTHY CRYO-SUPPLEMENTS

The aim of the work is to develop the new method of deep processing of spicy vegetables (ginger root, garlic, celery root, horseradish root) that gives a possibility to fully conserve volatile aromatic substances (ethereal oils, ketones, aldehydes, esters) and other biologically active substances (BAS) – phytocomponents of vegetable raw materials. At the same time this method gives a possibility to extract their hidden forms (bound in nanocomplexes with biopolymers, BAS) in the free soluble active form at receiving healthy semi-products (in puree form) and food products in the freely assimilated – nanosize form. For attaining this aim, cryogenic “shock” freezing and fine-dyspersated comminution using liquid and gas-like nitrogen with the modern equipment for cryo-processing and fine-dyspersated comminution was used as an innovation. There was developed the new method of getting healthy supplements and products of spicy vegetables (roots of ginger, celery, horseradish, garlic), cryo-processed using cryogenic liquid of liquid and gas-like nitrogen in the cryogenic fast-freezing apparatus and fine-dyspersately comminuted with the high content of aromatic phytosubstances, especially ethereal oils and other BAS, especially low-molecular phenol compounds, polyphenols, ascorbic acid and prebiotics. The new method of deep processing of spicy vegetables is based on the complex effect of processes of cryo-destruction, mechanodestruction and non-fermentative catalysis on raw materials at fine-dyspersated comminution. It was established, that at cryogenic “shock” freezing there takes place not only complete conservation of vitamins, aromatic substances, but their more complete extraction from the bound hidden form with biopolymers and BAS in the free one (1,7…2,5 times more that extracted from free vegetables). The quality of spicy vegetables 1,7…2,5 exceeds the quality of fresh vegetables and analogues. The essentially more effect of extracting hidden forms of aromatic substances and other BAS was revealed at low-temperature fine-dyspersated comminution of cryo-processed spicy vegetables. It was demonstrated, that at fine-dyspersated comminution there takes place 1,7…3,2 times more full extraction of hidden forms of low-molecular BAS than in fresh vegetables. Using new types of fine-dyspersated puree of spicy vegetables, there is developed the line of high-quality products for healthy nutrition with the stable texture and long storage life (juice nanodrinks, sauces-dressings, sauces-deeps, salted fillings for confectionary products, snacks, milk-vegetable products).

Fertilization Changes Chemical Defense in Needles of Mature Norway Spruce (Picea abies).

Nitrogen availability limits growth in most boreal forests. However, parts of the boreal zone receive significant levels of nitrogen deposition. At the same time, forests are fertilized to increase volume growth and carbon sequestration. No matter the source, increasing nitrogen in the boreal forest ecosystem will influence the resource situation for its primary producers, the plants, with possible implications for their defensive chemistry. In general, fertilization reduces phenolic compound concentrations in trees, but existing evidence mainly comes from studies on young plants. Given the role of the phenolic compounds in protection against herbivores and other forest pests, it is important to know if phenolics are reduced with fertilization also in mature trees. The evergreen Norway spruce is long-lived, and it is reasonable that defensive strategies could change from the juvenile to the reproductive and mature phases. In addition, as the needles are kept for several years, defense could also change with needle age. We sampled current and previous year needles from an N fertilization experiment in a Norway spruce forest landscape in south-central Norway to which N had been added annually for 13 years. We analyzed total nitrogen (N) and carbon (C), as well as low-molecular phenolics and condensed tannins. Needles from fertilized trees had higher N than those from controls plots, and fertilization decreased concentrations of many flavonoids, as well as condensed tannins in current year needles. In previous year needles, some stilbenes and condensed tannins were higher in fertilized trees. In control trees, the total phenolic concentration was almost five times as high in previous year needles compared with those from the current year, and there were great compositional differences. Previous year needles contained highest concentrations of acetophenone and stilbenes, while in the current year needles the flavonoids, and especially coumaroyl-astragalins dominated. Condensed tannins did not differ between current and previous year needles from control trees. In conclusion, the phenolic defense of current year needles of mature P.abies trees was strongly changed upon fertilization. This may imply that nitrogen deposition and forest fertilization leave forests less robust in a time when pests may take advantages of a changing climate.

ПРОСТРАНСТВЕННОЕ ВАРЬИРОВАНИЕ СОДЕРЖАНИЯ ВТОРИЧНЫХ МЕТАБОЛИТОВ, УГЛЕРОДА И АЗОТА В ПОДСТИЛКАХ СЕВЕРОТАЕЖНЫХ ЕЛЬНИКОВ*, "Лесоведение"

ПРОСТРАНСТВЕННОЕ ВАРЬИРОВАНИЕ СОДЕРЖАНИЯ ВТОРИЧНЫХ МЕТАБОЛИТОВ, УГЛЕРОДА И АЗОТА В ПОДСТИЛКАХ СЕВЕРОТАЕЖНЫХ ЕЛЬНИКОВ*, "Лесоведение"

Adsorption and separation of black liquor-derived phenol derivatives using anion exchange resins

Abstract Kraft black liquor is the major waste stream of the paper pulping industry. This stream is usually directly incinerated in such facilities for energy production and recycling of the inorganic chemicals involved. However, lignin and other low molecular organic fragments dissolved in black liquor give rise to a large variety of aromatic fine chemicals. Energetic use of black liquor and its components prevents the removal of these valuable compounds from the waste stream. We present an easy protocol for adsorption and selective desorption of low molecular phenol derivatives from black liquor depending on the composition of the desorption system. Furthermore, adsorption experiments in model systems provide a rationale for the selectivity of the desorption process. The described process represents a powerful technique for combination of adsorption of low molecular phenols derivatives from alkaline waste streams and online separation of the desired products with respect to their molecular structure.

Effects of various reaction parameters on solvolytical depolymerization of lignin in sub- and supercritical ethanol

Organosolv lignin was treated with ethanol at sub/supercritical temperatures (200, 275, and 350°C) for conversion to low molecular phenols under different reaction times (20, 40, and 60min), solvent-to-lignin ratios (50, 100, and 150mLg−1), and initial hydrogen gas pressures (2 and 3MPa). Essential lignin-degraded products, oil (liquid), char (solid), and gas were obtained, and their yields were directly influenced by reaction conditions. In particular, concurrent reactions involving depolymerization and recondensation as well as further (secondary) decomposition were significantly accelerated with increasing temperature, leading to both lignin-derived phenols in the oil fraction and undesirable products (char and gas).As the main components in the oil fraction, oxygenated phenols, guaiacol, and syringol as well as their alkylated forms were detected. The yield of alkylated phenols showed a drastic increase at 350°C in the presence of initial hydrogen gas due to prevailing hydrodeoxygenation and hydrogenation reactions of the vinyl/allyl/oxygenated phenols. These reactions were also demonstrated indirectly from the results of atomic H/C and O/C of the oils. The highest amount of monomeric phenols released from lignin (1.0g) was measured as ca. 96.7mg at 350°C, 40min, 100mLg−1, and 3MPa of H2. In addition, GPC analysis suggested a possibility of condensation between lignin-degraded fragments during the solvolysis reaction.

Structural factors responsible for the activity of macromolecular phenolic antioxidants

Hybrid macromolecular antioxidants based on hydrophilic polymers with chemically grafted sterically hindered phenol fragments in aqueous solution exhibited considerably higher antiradical activity than that typical of compositions consisting of a polymer and low-molecular phenol analogs. The activity of the examined antioxidants is determined mainly by formation of supramolecular structures in solution, as well as by the position of the phenolic fragment inside or outside hydrate shell. An important structural factor is the size of the spacer connecting the redox-active phenol ring with the polymer.

Topochemical Characterisation of Phenolic Extractives in Discoloured Beechwood (Fagus sylvatica L.)

Summary The topochemical distribution of phenolic extractives in steamed and kiln-dried beechwood with discolourations was investigated on a cellular level by using scanning UV microspectrophotometry (UMSP). For the chemical characterisation of accessory compounds, acetone and methanol extracts of the discoloured beechwood were separated by accelerated solvent extraction (ASE) and analysed with high performance liquid chromatography (HPLC). The UV microscopic investigations reveal that the accessory compounds responsible for the discolouration of beechwood are mainly restricted to the longitudinal and ray parenchyma cells and the lumen of vessels. The detected extractives are characterised by high UV absorbance values and an absorbance maximum in a wavelength range between 280 and 290 nm. The separation of the acetone and methanol extracts of discoloured beechwood shows the presence of different low molecular phenols such as catechin and 2,6-dimethoxybenzochinon, which are transformed into high condensation compounds during steaming and kiln-drying.

Dephenolisation of olive mill waste-waters by olive husk

Olive mill waste-waters (OMWW) are a by-product of olive-oil production and a major environmental problem in the Mediterranean area. The use of a polyphenol-oxidase from olive husk is proposed for the enzymatic removal of low-molecular phenolics in OMWW. For comparison purposes, a purified microbial polyphenol-oxidase ( Trametes versicolor laccase) was also employed. Though both enzymatic systems show relevant activity towards phenol polymerization, olive husk is much more appealing in view of possible applications because of its availability and extremely low cost, associated with excellent enzymatic activity and specificity.

クラフトパルプ製造時における樹脂の挙動と樹脂障害 （第２報） 工場における樹脂収支および種々のパルプ化条件下における樹脂挙動

This investigation was carried out to obtain a better understanding of the hydrolysis of methanol extractives (wood resin) and their removal including unsaponifiable materials from wood chips during pulping. The effect of active alkali charge and cooking time on the hydrolysis of wood resin and their removal were studied. The washing effect on the removal of wood resin was also examined.The results are summarizied as follows : 1. The neutrals of methanol extractives (wood resin) are completely hydrolyzed during kraft pulping by an active alkali charge of more than 15% to wood chips.2. The components readily soluble in an alkali-liquor such as low fatty acids and low molecular phenols are removed out of pulp during pulping without difficulty.3. Most of unsaponifiable materials in wood chips still remain in pulp after pulping.4. None of wood resin components is assumed to be able to pass through the cell wall unless they are dissolved in an alkali-liquor or organic solvents.5. The amount of unbleached pulp extractives dissolved in an alkali-liquor should be used as an indicator of washing efficiency for unbleached pulp instead of total amount of extractives in pulp.

PHENOLIC SUBSTANCES IN A HUMUSPODZOL PROFILE AND THEIR IMPACT ON SOME WOODLAND HERBS AT LOW NUTRIENT SUPPLY

Twelve years after clearance of a Picea abies stand, the spectrum of water-soluble phenolic acids in the soil still resembled that of an adjacent, undamaged stand. Ferulic and p-coumaric acid were the predominant phenolic compounds. Apparently, the spectrum of low molecular phenolics in the soil layers is affected by the original litter material over a long period. The concentrations of water-soluble acids was highest in the A0-horizon. A comparison between the sites revealed that concentrations in the clearing were reduced with more than 50% compared to the undamaged stand. The significance of the phenolic acids for plant growth was investigated for two herbaceous woodland (-clearing) species, Senecio sylvaticus and Chamaenerion angustifolium. Both species were tested for their sensitivity to phenolic acids in dependence of nutrient supply under greenhouse conditions. Severe growth reduction occurred at high phenolic acid concentrations (10–3 M). Plants that were restricted in growth by a low nutrient supply, were less affected by the intermediate phenolic acid concentrations of 10–5 and 10–4 M than plants grown at high nutrient supply. The results are discussed in view of vegetation succession on woodland clearings.

ＳＤＳによるアクトミオシンからのフェノール試薬陽性物質の遊離

On heating actomyosin (AM) solution from various fish species at 60°C, low molecular phenol reagent-positive substances were slowly liberated. However, a remarkable liberation was induced also by the addition of 0.4% (w/v) sodium dodecylsulfate (SDS) to the solution. On heating the solution under the presence of SDS at this temperature, the liberation was completed within 30 minutes. SDS did not influence the blue coloration of tyrosine with phenol reagent.The unheated AM solution was treated with chloroform-methanol (2: 1), and fractionated to the protein fraction, water-soluble fraction and oil fraction. The last two fractions were phenol reagent-positive, and the water soluble fraction agve a ninhydrin positive test. The phenol reagent-positive substance in the oil fraction was identified as α-tochopherol.From the above results, it was suggested that the AM molecule included large quantities of phenol reagent-positive substances, such as amino acids and α-tochopherol, among its subunits, and that it released them during heating.