New aspects in cationization of lignocellulose materials. IV. Modification of aspen wood meal with quarternary ammonium groups

Trimethylammonium-2-hydroxypropyl (TMAHP) derivatives of aspen wood were prepared by the reaction of wood meal with 3-chloro-2-hydroxypropyltrimethylammoniumchloride (CHMAC) in alkaline medium. The TMAHP sample was fractionated and yields and exchange capacities (Q) of individual fractions were compared with beech sawdust fractions obtained under the same conditions. The most evident difference between the two studied wood types was the higher yield (14.5% of starting material) of water-soluble TMAHP–hemicelluloses obtained from aspen wood.     

New aspects in cationization of lignocellulose materials. V. Modification of rotten aspen wood meal with quarternary ammonium groups

Holocelluloses prepared from clear and rotten aspen wood were gradually fractionated with 2.5% NH₄OH, 4.5% NaOH, and 17.5% NaOH, respectively. A higher yield of polysaccharides (24.4%) was obtained from the rotten sample in comparison with clear wood (20.9%). Trimethyl ammonium-2-hydroxypropyl (TMAHP) derivatives of rotten aspen were prepared by the reaction of wood with 3-chlor-2-hydroxypropyltrimethylammoniumchloride (CHMAC) in alkaline medium. The quantity of TMAHP—hemicelluloses (yield 14.1%) is only slightly lower in comparison with TMAHP—hemicelluloses (yield 15.8%) obtained by modification and subsequent extraction from clear aspen wood meal. The hemicelluloses isolated from the rotten aspen wood meal are contaminated with low molecular cellulose fraction, the degradation products of cellulose attacked by fungi. The lignin component of rotten wood is less intensively attacked by fungi than the polysaccharidic one.     

New aspects in cationization of lignocellulose materials. VI. Modification of steam-exploded aspen wood chips with quarternary ammonium groups

Holocellulose prepared from steam-exploded aspen wood was gradually fractionated with 2.5% NH₄OH, 4.5% NaOH, and 17.5% NaOH, respectively. Some residual polysaccharides were extracted from the material in this way, but their yield was only about 5%. Trimethylammonium-2-hydroxypropyl (TMAHP)-derivatives, exploded aspen wood (EXAW), were prepared by the reaction with 3-chlor-2-hydroxypropyl trimethylammoniumchloride (CHMAC) in alkaline medium. The quantity of water and alkali extracted TMAHP–polysaccharides (yield 2.6%) was lower than the yields from modified healthy beech and aspen, as well as rotten aspen. On the other hand, we can obtain more modified cellulose-rich and lignin-rich material than from previously mentioned species. The steam-explosion process is suitable for increasing the accessibility of cellulose component in lignocellulose material for chemical modification.     

Chemical conversion of wood by treatment in a semi-batch reactor with subcritical water

Sugi (Cryptomeria japonica D. Don) wood meal was extracted with subcritical water in a semi-batch reactor. About 70–90% by weight of the sugi wood meal was converted into water-soluble compounds. The main components of the water-soluble compounds were monosaccharides and oligosaccharides, as a result of hydrolysis of cellulose and hemicellulose. White precipitates appeared in the solution after settling for 48 h. X-ray diffractometry clearly showed that precipitates had crystallized into cellulose II. High yield of total saccharides (including the precipitates) was obtained at 310–320 °C, 25 MPa and 65 g min⁻¹ water flow rate from a wood meal charge of 2.0 g, while the decomposition reaction was completed within about 20 min. Moreover, the yield increased to more than 60% when the wood meal was pretreated for improved wettability. It is shown that saccharides can be produced from sugi wood powder quickly and effectively by treatment in subcritical water.     

New aspects in cationization of lignocellulose materials. VIII. Modification of immitted spruce wood with quarternary ammonium groups

Immitted spruce wood meal (ISWM) was modified with 3-chlor-2-hydroxypropyltrimethyl-ammoniuchloride (CHMAC) or 1,3-bis(3-chlor-2-hydroxypropyl)imidazoliumhydrogensulphate (BCHIHS) in alkaline medium. The obtained material was gradually extracted with water and 5% NaOH. The yields of water-soluble hemicelluloses modified with quarternary ammonium groups were lower in comparison to healthy spruce material obtained under the same conditions but even more material could be obtained from ISWM-holocellulose. The quantity of alkali-soluble polysaccharides from ISWM was the same as obtained from undamaged spruce. The residues after alkali extractions are suitable ion exchangers with low solubility in dilute alkali solutions. The yields of extracts from material modified with BCHIHS were lower than yields of extracts from material modified with CHMAC because ISWM was crosslinked when alkylated with bifunctional chemicals.     

Fractional Separation of Hemicelluloses and Lignin in High Yield and Purity from Mild Ball-Milled Periploca sepium

Abstract

A novel three-step procedure for separation of hemicelluloses and lignin with high yield and purity was proposed in this study, where wood is mildly milled and successively extracted to produce three hemicellulosic and lignin fractions representing the total hemicelluloses and lignin in wood. The sequential treatments of the mild ball-milled Periploca sepium with 80% aqueous dioxane containing 0.05 M HCl at 85°C for 4 h, DMSO at 85°C for 4 h, and 8% NaOH at 50°C for 3 h resulted in a total release of over 85% of the original hemicelluloses and 86% of the original lignin. In particular, approximately 36% of the original hemicelluloses and 50% of the original lignin were separated during the first mild acidolytic hydrolysis process after low intensity milling. The structure of the acidic dioxane-, DMSO-, and alkali-soluble hemicellulosic and lignin fractions were elucidated using wet chemical analysis, FT-IR, and solution-state ¹H, ¹³C, and ³¹P NMR techniques. Results showed that both the mild ball milling and the mild acidolysis under the conditions given did not affect the separated lignin macromolecular structure. On the other hand, the mild acidolytic hydrolysis condition did cause substantial hemicellulosic depolymerization exception for a significant cleavage the ether linkages between lignin and hemicelluloses. The acidic dioxane-soluble lignin fraction was structurally different from the DMSO- and alkali-soluble lignin preparations and may originate mainly from the primary wall, while the alkali-soluble lignin preparation was mainly released from the secondary wall of Periploca sepium. Furthermore, it was found that the acidic dioxane-soluble hemicelluloses mainly contained more branched and less acidic arabinoxylans, and the 8% NaOH-soluble hemicellulosic fraction H₃ was both less branched and less acidic in structure, whereas the DMSO-soluble hemicelluloses were more acidic but less branched and consisted mainly of 4-O-methylglucuronoarabinoxylan.     

Direct liquefaction of different lignocellulosics and their constituents: 1. Fractionation,elemental composition

Oils have been produced thermochemically from the following lignocellulosic materials by applying constant hydrogenolytic conditions in an aqueous phase with palladium as catalyst : spruce and birch wood, spruce and birch holocellulose, cellulose, pine bark, spruce and bagasse organosolv lignins, and birch Willstätter lignin. The liquid products were separated into water-, acetone- and dichloromethane-soluble (oil) fractions. The highest oil yield was obtained from spruce organosolv lignin (64%) and the lowest from carbohydrates and pine bark (20–31%). The oils were separated into neutral, strongly acidic and weakly acidic fractions by a liquid/liquid extraction procedure. Sequential elution by solvent chromatography was used for additional comparative characterization of the oils. Calorific values of the feedstocks and oils were calculated based upon the data of elemental analysis.     

Effects of pretreatment temperature and alkali concentration on the composition of alkali-soluble lignins from wheat straw

A new rapid method of two step precipitation for isolation of alkali-soluble lignins with relatively free of polysaccharides from wheat straw was proposed in this study. The isolated alkali-soluble lignin fractions LA contained rather low amounts of neutral sugars (0.7–1.0%) and had low average molecular weights (960–1440 Da). The isolated lignin fractions LA contained roughly equal amounts of guaiacyl (G) and syringly (S) units with relatively fewer p-hydroxyphenyl (H) units, and appeared to be closely associated to phenolic acids and glucuronic acid or 4-O-methylglucuronic acid. The chemical compositions in each of the fractions are reported. The physico-chemical properties and structure features of these lignin fractions LA were characterized by UV-, IR-, ¹³C-NMR-spectroscopy, and alkaline nitrobenzene oxidation. © 1996 John Wiley & Sons, Inc.     

Miscanthus sinensis fractionation by different reagents

Miscanthus sinensis L. was fractionated by different reagents (ethanol, soda and soda–ethanol) in order to obtain cellulose, hemicelluloses and lignin. Characterization of original M. sinensis fibres (66.6% holocellulose, 36.1% α-cellulose, and 15.5% lignin) was done and compared with other biomass species chemical composition (alternative raw materials, agriculture residues, coniferous and leafy plants). Obtained solid fractions were chemically characterized and compared with solid fractions from other biomass products (palm oil empty fruit bunches (EFB) and rice straw) generated by similar fractionation processes (soda and organosolv). Soda process produced the solid fraction with the highest content in α-cellulose and lowest content in lignin revealing a strong fractionation effect. On the contrary, soda–ethanol process was found to present low fractionation capability. Obtained cellulose samples were characterized by FTIR to complete the chemical structure analysis. Lignin samples isolated from the liquid fractions were submitted to FTIR, ¹H NMR, GPC, DSC and TGA in order to suggest suitable applications for the products based on their properties.     

New aspects in cationization of lignocellulose materials. III. Influence of delignification on reactivity and extractability of TMAHP–hemicelluloses

Beech sawdust samples with different lignin content were alkylated with 3-chloro-2-hydroxypropyltrimethylammoniumchloride (CHMAC). The yields and the degree of subtitution of trimethylammonium-2-hydroxypropyl (TMAHP) samples were similar. Differences were found in extractability of hemicelluloses from this materials both with water and dilute alkali. To obtain the maximum yield of TMAHP–hemicelluloses (ca. 90% of the amount originally present), it is sufficient to remove about 50% of lignin. The lignin component does not influence the reactivity of hemicelluloses. The isolated hemicelluloses differ only in the distribution of functional groups and extractability.     

Elimination of toxic compounds, biological evaluation and partial characterization of the protein from jojoba meal (Simmondsia chinensis [Link] Schneider

The purpose of this study was to establish a new methodology to remove the toxic compounds present in jojoba meal and flour. Also, to perform the biological evaluation of the detoxified products and to chemically characterize the protein fractions. Jojoba meal and seed without testa were deffated with hexane and detoxified with a 7:3 isopropanol-water mixture which removed 86% of total phenolic compounds and 100% of simmondsins originally present, the resulting products had reduced bitterness and caused no deaths on experimental animals. NPR values obtained for diets containing such products were significantly different from those obtained with the casein control (p less than 0.05). Total protein was made up of three different fractions: the water-soluble fraction was the most abundant (61.8%), followed by the salt-soluble (23.6%), and the alkaline soluble fraction (14.6%). The nitrogen solubility curves showed that the isoelectric point for the water-soluble and salt-soluble fractions was pH 3.0, while that of the alkaline fraction fell in the range of 4.5-5.0. All fractions had a maximum solubility at pH 7.0. The methodology reported here, offers a viable solution to eliminate toxic compounds from jojoba meal or seeds, and upgrades the potential use of products such as animal feed or raw material for the production of protein isolates.     

Effects of Toasting Time on Digestive Hydrolysis of Soluble and Insoluble 00-Rapeseed Meal Proteins

Thermal damage to proteins can reduce their nutritional value. The effects of toasting time on the kinetics of hydrolysis, the resulting molecular weight distribution of 00‐rapeseed meal (RSM) and the soluble and insoluble protein fractions separated from the RSM were studied. Hydrolysis was performed with pancreatic proteases to represent in vitro protein digestibility. Increasing the toasting time of RSM linearly decreased the rate of protein hydrolysis of RSM and the insoluble protein fractions. The extent of hydrolysis was, on average, 44% higher for the insoluble compared with the soluble protein fraction. In contrast, the rate of protein hydrolysis of the soluble protein fraction was 3–9‐fold higher than that of the insoluble protein fraction. The rate of hydrolysis of the insoluble protein fraction linearly decreased by more than 60% when comparing the untoasted to the 120 min toasted RSM. Increasing the toasting time elicited the formation of Maillard reaction products (furosine, N^ε‐carboxymethyl‐lysine and N^ε‐carboxyethyl‐lysine) and disulfide bonds in the insoluble protein fraction, which is proposed to explain the reduction in the hydrolysis rate of this fraction. Overall, longer toasting times increased the size of the peptides resulting after hydrolysis of the RSM and the insoluble protein fraction. The hydrolysis kinetics of the soluble and insoluble protein fractions and the proportion of soluble:insoluble proteins in the RSM explain the reduction in the rate of protein hydrolysis observed in the RSM with increasing toasting time.     

Protein fractionation and properties of salicornia meal

Salicornia bigelovii Torr. is an annual salt-marsh oilseed plant. Hexane-defatted salicornia meal was extracted sequentially with 0.5 M sodium chloride (2x), water, 70% ethanol, and 0.1 N sodium hydroxide (2x). Each sodium chloride extract was dialyzed against deionized water and centrifuged to separate a water-soluble fraction (albumin) from a salt-soluble fraction (globulin) before freeze-drying. Ethanol extracts and neutralized sodium hydroxide extracts (glutelin) were dialyzed against water and freeze-dried. Globulin accounted for the highest amount of protein nitrogen, followed by glutelin and albumin. SDS-PAGE of reduced albumin, globulin, and glutelin showed a number of protein bands. Nitrogen solubility of defatted salicornia meal from pH 2 to 11 indicated a minimum solubility of 22%, around pH 4.5. Nonprotein nitrogen of defatted meal was 23% of total nitrogen, higher than defatted soybean, sunflower, and rapeseed meals. Albumin had the highest proportion of lysine and sulfur amino acids per 16 g nitrogen among all the fractions analyzed.     

Chemical and functional characterization of major protein fractions extracted from nontoxic Jatropha curcas byproduct meals

Jatropha curcas seeds are a suitable source of oil for biofuel, among other use. A protein-rich meal is obtained after oilseed extraction. The goals of this study were to determine the physicochemical and functional properties of a nontoxic genotype of J. curcas defatted meal (JCDM) and the seed storage protein fractions to identify future applications. Both glutelin and globulin were the predominant protein fractions obtained from JCDM (42.03 and 20.17 g/100 g of protein, respectively). Leucine, phenylalanine + tyrosine, and histidine content of JCDM and protein fractions met the Food and Agriculture Organization/World Health Organization recommendation for children. The protein solubility (PS) profiles showed minimum values (5.3%–59.7%) at pH 5–6 and maximum at pH 2 (79.7%–81.6%) and above pH 10 (84.6%–89.8%). These findings suggest that JCDM proteins could be used in the formulation of juice or protein-based beverages. All the proteins showed the highest values for foam expansion (231%–285%) at pH 9. JCDM and the albumin fraction formed highly stable foams at pH 9, while the globulin and glutelin foams were stable at pH 3 and 2, respectively. Protein with stable foams, like those from jatropha are suitable for application in ice cream, mousse, among others. The emulsion activity index had similar behavior as foam expansion, but did not follow a specific trend. Thus, the proteins are suitable for use in salad dressing, sausages, comminuted meats, and mayonnaise. Taken together, JCDM protein and its soluble protein fractions have strong promise as alternative proteins for food structuring.     

Non-destructive Determination of Wood Constituents by Fourier Transform Raman Spectroscopy

The feasibility of using FT-Raman spectroscopy for rapid determination of various wood constituents non-destructively was examined using five Eucalyptus species, including samples of various ages and colors of samples, which are of importance as a plantation source. Wood constituents which relate to pulp properties (holocellulose, α -cellulose, hemicellulose, lignin, extractives, alkali-extractives, total-extractives, and extractives-free (EF) wood constituents for holocellulose, α -cellulose, hemicellulose and lignin) were measured. The application of 2nd derivatives transformation of Raman spectroscopic data revealed highly significant correlations between wet chemical and Raman predicted values for all traits except EF-hemicellulose, with standard error of prediction (SEP) < 0.8 points in the calibration (for known samples) and SEP < 3.4 points in the prediction (for unknown samples), respectively. Consequently, this non-destructive method has proved its validity for analyzing various Eucalyptus native wood meal samples, regardless of their age and color, to determine wood constituents and EF-wood constituents except hemicellulose. Use of this method will reduce the costs of tree improvement programs and the minimal sample size needed will allow trees to be non-destructively sampled.     

Isolation and Analysis of the Hemicelluloses of the Fossil Tree (Metasequoia Glyptostroboides)

The hemicelluloses of the fossil tree (Metasequoia glyptostroboides) were isolated from a mildly-prepared acid chlorite holocellulose. Arabinoxylan, glucomannan, and galactoglucomannan were isolated from the holocellulose by extraction and fractionation techniques. The sugar compositions of the polysaccharides were analyzed by quantitative thin layer chromatography and gas chromatography. The hemicelluloses accounted for 21–22% of the wood; the arabinoxylan about 10%, the glucomannan about 6.3%, and the galactoglucomannan about 4.8%. The glucose:mannose ratio for the glucomannan and galactoglucomannan were approximately 1:1.6 and 1:1.7, respectively, in contrast to a ratio of 1:3 commonly found in coniferous woods.     

Thermal softening and melting of esterified wood prepared in an N2O4–DMF cellulose solvent medium

The thermal softening and melting of a series of esterified wood samples, whose preparation has previously been described,⁴ have been studied by measuring the deformation of the samples under constant load at a constant heating rate. The introduction of acyl groups into wood including part of the original crystal structure in cellulose makes the modified wood meal conspicuously thermoplastic. While untreated dry wood shows a thermal softening point (T_s) of ca. 260°C, esterified wood meal samples with acyl groups larger than caproyl have a T_s of around 100°C or less, and appeared to melt over the temperature range of 220° to 250°C. In this case, the melting occurs even with wood meal samples esterified with appropriate acid chlorides in an N₂O₄–DMF–pyridine medium only for 30 min at room temperature. This might be the first finding that wood meal is converted, as a whole, into a thermoplastic material which can melt without any accompanying detectable degradation.     

Mineralization and nitrification of ureaform fertilizers

In an attempt to produce N materials that exhibit some delayed-release character and yet make all the N available in one growing season, ureaform (UF) fertilizers were prepared using low amounts of paraformaldehyde (PFA) (6% to 15% PFA w/w). Mineralization and nitrification of the various water-soluble components of these UF materials were studied over a period of 35 days by use of¹⁵N and high pressure liquid chromatographic techniques. Only the dimethylenetriurea (DMTU) fraction and a fraction tentatively identified as triuret showed any slow-release character, whereas other water-soluble components mineralized rapidly. Less soluble fractions did not mineralize appreciably during the experiment. Due to their reduced solubility, these ureaforms were shown to be less susceptible to volatilization than was urea, and a 37% reduction in loss was found.     

Lignin Degradation by Flavodon flavus (Klotzsch.) Ryv. and Schizophyllum commune Fr. on Mangifera indica and Syzygium cumini Woods

Abstract

The lignin degradation by Flavodon flavus (Klotzsch) Ryv. and Schizophyllum commune Fr. on Mangifera indica and Syzygium cumini wood, changes in the chemical composition of the degraded wood, and production of extra-cellular lignocellulolytic enzymes were analyzed. White rot fungi F. flavus and S. commune selectively degraded the lignin of S. cumini rather than the holocellulose component, whereas simultaneous degradation of lignin occurred in the case of M. indica. After 90 days of pretreatment with F. flavus, total weight loss was 29% and loss in lignin content was 25.7% in M. indica wood. However, 8% loss of holocellulose was caused by S. commune in S. cumini wood. Extracellular enzymes from F. flavus such as ligninase and cellulase showed higher activity in degradation of M. indica wood than in S. cumini wood. Weight loss and changes in chemical composition of M. indica and S. cumini woods showed good correlation with enzyme activity in lignocellulose degradation. Woods of S. cumini showed resistance to the white rot fungi could be due to the presence of polyphenols.     

Wood preservation by a mixed anhydride treatment: A 13C‐NMR investigation of simple models of polymeric wood constituents

The treatment of wood by a mixed aceto/oleic (or other fatty acid residue) anhydride promoted as a safe and environmentally friendly wood preservation system was examined quantitatively by liquid‐phase ¹³C‐NMR and solid‐phase magic angle spinning–DEC (proton decoupling) ¹³C‐NMR through of all its different stages to determine which reactions occurred with simple model compounds of the polymeric constituents of wood. The preparation of the mixed aceto/oleic anhydride under different conditions was also undertaken. The anhydride formed, but its percentage yield was only 30%. The mix composed of unreacted acetic anhydride, the mixed aceto/oleic anhydride, and a large proportion of free acetic and oleic acid, which are used for wood preservation, yielded the acetylation of the lignin model compound (1) by the reaction of the acetic anhydride with it and (2) by the reaction of the acetic part of the mixed anhydride. In this reaction, all of the mixed anhydride was consumed. The oleic part of the mixed anhydride was unable to form esters with either lignin or wood holocellulose as it was far less reactive than the acetic part. Some acetylation of holocellulose occurred, and some traces of its oleic acid ester also occurred under some conditions. This system of treatment through a mixed anhydride appeared to consist of just an acetylation with acetic anhydride mixed with some oleic acid as a water repellent, both of which are already known processes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009