Optimization of the extraction of galactoglucomannans from Pinus halepensis

The effectiveness of pressurized hot-water extraction conditions for obtaining galactoglucomannans (GGMs) from Pinus halepensis suitable for applications like coatings and films packaging was investigated. For this purpose, high molar masses with high yields are required, presenting a serious challenge for hot-water extraction processes. The extraction of GGMs was carried out in an accelerated solvent extractor (ASE) and the isolation was performed by precipitation in ethanol. Three temperatures in the range 160-180 degrees C and five extraction times 5-90 min were tested in order to optimize extraction parameters of GGMs, avoiding thermal and chemical degradation in hotwater. Total dissolved solids (TDS) were determined gravimetrically after freeze-drying and weight average molar masses (Mw) were determined by high-performance size exclusion chromatography (HPSEC). Total non-cellulosic carbohydrates were determined by gas chromatography (GC) after acid methanolysis. Free monomers were additionally analyzed by GC. Lignin in water extracts was measured by an ultraviolet (UV) method. Acetic acid was determined after alkaline hydrolysis of acetyl groups and analyzed by HPSEC. The main parameters influencing the extraction processes of the GGMs, namely, extraction time and temperature were studied. Optimal extraction parameters of GGMs were identified at 170 degrees C and 20 min extraction time, with average Mw of extracted fraction of 7 kDa leading to a GGM yield of approximately 56 mg g(o.d.m)(-1) corresponding to 6% on dry wood basis.This work was part of the doctoral research activities of ((insert author name/s)) at the Johan Gadolin Process Chemistry Centre (PCC) at Abo Akademi University, Finland. We thank The Algerian Ministry of Higher Education and Scientific Research for funding support within "Le Projet National Exceptionnel (P.N.E)'

Phenolic residues in spruce galactoglucomannans improve stabilization of oil-in-water emulsions

Hypothesis: Amphiphilic character of surfactants drives them at the interface of dispersed systems, such as emulsions. Hemicellulose-rich wood extracts contain assemblies (lignin-carbohydrate complexes, LCC) with natural amphiphilicity, which is expected to depend on their chemical composition resulting from the isolation method. Lignin-derived phenolic residues associated with hemicelluloses are hypothesized to contribute to emulsions' interfacial properties and stability. Experiments: We investigated the role of phenolic residues in spruce hemicellulose extracts in the stabilization of oil-in-water emulsions by physical and chemical approach. Distribution and changes occurring in the phenolic residues at the droplet interface and in the continuous phase were studied during an accelerated storage test. Meanwhile, the physical stability and lipid oxidation in emulsions were monitored. Findings: Naturally associated lignin residues in GGM act as vehicles for anchoring these hemicelluloses into the oil droplet interface and further enable superior stabilization of emulsions. By adjusting the isolation method of GGM regarding their phenolic profile, their functionalities, especially interfacial behavior, can be altered. Retaining the native interactions of GGM and phenolic residues is suggested for efficient physical stabilization and extended protection against lipid oxidation. The results can be widely applied as guidelines in tailoring natural or synthetic amphiphilic compounds for interfacial stabilization. (C) 2017 Elsevier Inc. All rights reserved.Peer reviewe

Recovery of Bioactive Compounds from Hazelnuts and Walnuts Shells: Quantitative–Qualitative Analysis and Chromatographic Purification

Hazelnut (HS) and walnut (WS) shells, an abundant by-product of the processing industries of these edible nuts, are traditionally considered as a low-value waste. However, they are a source of valuable compounds with an interesting chemical profile for the chemical and pharmaceutical sectors. In this study, the lipophilic and hydrophilic extracts present in HS and WS were quantified and identified, then the polar fractions were chromatographically separated, and their antioxidant capacity was studied. The experimental work includes the isolation of crude lipophilic and hydrophilic extracts by an accelerated extraction process, chromatographic analysis (gas chromatography-flame ionization (GC-FID), GC-mass spectroscopy (GC-MS), high-performance size-exclusion chromatography (HPSEC), thin-layer chromatography (TLC)), and quantification of the components. In addition, a thorough compositional characterization of the subgroups obtained by flash chromatography and their antioxidant capacity was carried out. The gravimetric concentrations showed different lipophilic/hydrophilic ratios (0.70 for HS and 0.23 for WS), indicating a higher proportion of polar compounds in WS than in HS. Moreover, the lipophilic extracts were principally composed of short-chain fatty acids (stearic, palmitic, and oleic acid), triglycerides, and sterols. The polar fractions were screened by thin-layer chromatography and then separated by flash chromatography, obtaining fractions free of fatty acids and sugar derivatives (97:3 in HS and 95:5 in WS), and mixtures richer in phenolic compounds and flavonoids such as guaiacyl derivatives, quercetin, pinobanksin, and catechin. The most polar fractions presented a higher antioxidant capacity than that of the crude extracts.This work was supported by the Basque Government (Grupos Consolidados IT-1264-19). U.G.-G. was supported by Fundación Biofísica Bizkaia. A.B.-V. was supported by Programa de especialización de Personal Investigador Doctor en la UPV/EHU (2019) 2019–2020. S.J.-B. and A.L.-S. were supported by a grant PIF (2017–2018) and (2019–2020), Gobierno Vasco, respectively. A.L.-S. was partially supported by Fundación Biofísica Bizkaia

Ultralight and porous cellulose nanofibers/polyethyleneimine composite aerogels with exceptional performance for selective anionic dye adsorption

It is significant to develop new adsorbents with excellent adsorption performance and convenient operation ability for removing pollutants from wastewater owing to the growing environmental problems. In this paper, a novel ultralight aerogel-based adsorbent with highly porous structure and good mechanical integrity was fabricated based on the interaction of amine groups on polyethyleneimine (PEI) and hydroxyl groups on cellulose nanofibers (CNF), with epichlorohydrin (ECH) serving as a crosslinker. The obtained CNF/PEI aerogel showed excellent water stability in harsh conditions, fast water-activated shape recovery, and ultra-fast water transport. The adsorption capacity for methyl orange (MO) in batch can reach to1226 mg g−1 at pH 6. Furthermore, the membrane also exhibited excellent selective adsorption and filtration, and separation performance. Therefore, this paper presents a new strategy to prepare low-cost and highly efficient adsorbents to remove organic dyes from wastewater for potential practical applications.</p

Films from Glyoxal-Crosslinked Spruce Galactoglucomannans Plasticized with Sorbitol

Films were prepared from a renewable and biodegradable forest biorefinery product, spruce O-acetyl-galactoglucomannans (GGMs), crosslinked with glyoxal. For the first time, cohesive and self-standing films were obtained from GGM without the addition of polyol plasticizer. In addition, glyoxal-crosslinked films were prepared using sorbitol at 10, 20, 30, and 40% (wt.-% of GGM). Glyoxal clearly strengthened the GGM matrix, as detected by tensile testing and dynamic mechanical analysis. The elongation at break of films slightly increased, and Young's modulus decreased with increasing sorbitol content. Interestingly, the tensile strength of films was constant with the increased plasticizer content. The effect of sorbitol on water sorption and water vapor permeability (WVP) depended on relative humidity (RH). At low RH, the addition of sorbitol significantly decreased the WVP of films. The glyoxal-crosslinked GGM films containing 20% sorbitol exhibited the lowest oxygen permeability (OP) and WVP of the studied films and showed satisfactory mechanical performance

The Hydrophobicity of Lignocellulosic Fiber Network Can Be Enhanced with Suberin Fatty Acids

Suberin fatty acids were extracted from outer bark of Silver birch (Betula pendula Roth.) using an isopropanolic sodium hydroxide solution. Laboratory sheets composed of lignocellulosic fiber networks were prepared from unbleached and unrefined softwood kraft pulp and further impregnated with suberin fatty acid monomers and cured with maleic anhydride in ethanol solution. The treatment resulted in hydrophobic surfaces, in which the contact angles remained over 120 degrees during the entire measurement. The fiber network also retained its water vapor permeability and enhanced fiber–fiber bonding resulted in improved tensile strength of the sheets. Scanning electron microscopy (SEM) images revealed that the curing agent, together with suberin fatty acids, was evenly distributed on the fiber surfaces and smoothing occurred over the wrinkled microfibrillar structure. High concentrations of the curing agent resulted in globular structures containing betulinol derivates as revealed with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Also, the larger amount of suberin fatty acid monomers slightly impaired the optical properties of sheets

The Hydrophobicity of Lignocellulosic Fiber Network Can Be Enhanced with Suberin Fatty Acids

Suberin fatty acids were extracted from outer bark of Silver birch (Betula pendula Roth.) using an isopropanolic sodium hydroxide solution. Laboratory sheets composed of lignocellulosic fiber networks were prepared from unbleached and unrefined softwood kraft pulp and further impregnated with suberin fatty acid monomers and cured with maleic anhydride in ethanol solution. The treatment resulted in hydrophobic surfaces, in which the contact angles remained over 120 degrees during the entire measurement. The fiber network also retained its water vapor permeability and enhanced fiber–fiber bonding resulted in improved tensile strength of the sheets. Scanning electron microscopy (SEM) images revealed that the curing agent, together with suberin fatty acids, was evenly distributed on the fiber surfaces and smoothing occurred over the wrinkled microfibrillar structure. High concentrations of the curing agent resulted in globular structures containing betulinol derivates as revealed with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Also, the larger amount of suberin fatty acid monomers slightly impaired the optical properties of sheets

Environmentally-compatible alkyd paints stabilized by wood hemicelluloses

Wood biorefining currently involves large-scale industrial processes where a notable portion of raw materials, namely hemicelluloses and lignin, are either lost with the process water, degraded, or burnt for energy. Value added utilization of polymeric hemicelluloses is challenging due to their intermediate molar mass and the presence of other wood components, such as phenolic residues or wood extractives. Oil-in-water (O/W) emulsions represent a diverse and abundant class of applications in which the natural properties of wood hemicelluloses are beneficial. In the current work, we present highly promising new technical alkyd paint emulsion systems stabilized with hardwood glucuronoxylans (GX) and softwood galactoglucomannans (GGM). Samples from three isolation methods and their further fractionation by ethanol precipitation were systematically compared with regard to hemicellulose composition, interfacial activity, and functionality in emulsions. Emulsification of alkyd resins was successful with both GX and GGM obtained by various biorefining strategies. The highest emulsion stability over storage was achieved using crude non-purified GX and GGM fractions, and was correlated with the presence of phenolic compounds and extractives, interfacial activity, and small droplet size. Hardwood GX and softwood GGM are envisioned as natural emulsifiers of alkyd O/W emulsions, which are examples of diverse and abundantly-used technical dispersions. This study can be utilized as a guideline for targeted extraction of hemicelluloses with desired functionality, and as a protocol for developing environmentally-compatible industrial dispersions.Peer reviewe

Intake of Radionuclides in the Trees of Fukushima Forests 4. Binding of Radioiodine to Xyloglucan

The 1, 4-linked glucans such as xyloglucan and amylose are known to form a complex with iodine/iodide ions and to also be precipitated with CaCl2 in the presence of iodine. Here, we show that iodine gas could be specifically incorporated into xyloglucan. Furthermore, we show that [125I]I2 gas is, over time, incorporated at high levels into the entire outer surface of poplar seedlings but that spraying seedlings with abscisic acid to close stomata decreases the incorporation of the gas. There was less incorporation of the gas in a transgenic poplar overexpressing xyloglucanase at the early stages when compared with a wild type. This shows that xyloglucan serves as a key absorber of iodine gas into a plant body. After individual leaves of cultured seedlings were exposed to the gas for 30 min, no radioiodine was emitted from those leaves over the following two weeks, indicating that no turnover occurs in radioiodine once it is bound to the polysaccharides in plant tissues. We conclude that forest trees could serve as one of the largest enormous capture systems for the radioiodine fallout following the nuclear power plant accident in Fukushima