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Etherification routes using epoxy reagents in alkaline conditions. (i) xylan is hydroxypropylated using propylene oxide; (ii) xylan is only etherified using butyl and allyl glycidyl ethers; (iii) hydroxypropylated xylan is further etherified using butyl and allyl glycidyl ethers (1). Hydroxypropylated (HPX); (2) butyl-allylated (X-BA) and (3) hydroxypropylated and butyl-allylated (HPX-BA) xylans.
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This paper demonstrates opportunities for wood-based xylan derivatives to be used in coating applications. A route for extraction and purification of white and pure xylan from bleached birch kraft pulp is described as a part of the production of high adsorption and high crystalline pulp. Derivatization of the xylan during the extraction step was al...
Citations
... Besides structural changes like cleavage of acetyl groups, hemicelluloses did apparently not undergo significant hydrolysis and largely remained in the material as the concentration of xylose and 4-O-methylglucuronic acid (4-OMeGlcUA) did not change markedly upon alkalipretreatment thus indicating the presence of xylan in A-MH-OPT (Table 1). This is in line with the findings of Laine et al. [47] who reported that under mild alkaline pre-treatment conditions, hemicelluloses remain mostly intact but experience different chemical changes like removal of acetyl and uronic acid groups as well as saponification of ester bonds that link hemicellulose to other lignocellulosic components. The bands at around 1594 and 1505 cm −1 are assigned to aromatic skeletal vibration in lignin [17] and may thus serve as an indicator for assessing the extent of lignin removal. ...
Oil palm trunk (OPT) is an inexpensive, abundantly available by-product of palm oil production which is typically not put to material use. Due to its comparably high cellulose content, OPT represents a suitable raw material for the preparation of cellulose nanofibrils (CNFs). Aiming for full utilization of the raw material and minimized energy demand, non-delignified and partially delignified (alkali-pretreated) OPT was subjected to mechanical fibrillation in the present study. As compared to CNFs from fully delignified OPT, the lignin-rich microfibrils obtained by this approach generally showed higher average fibril diameters, lower thermal stability as well as lower viscosity, and higher sedimentation rate in suspension. However, the combination of alkali-pretreatment and fibrillation by disc-grinding and subsequent high-pressure homogenization resulted in fibrils with properties similar to those of CNFs from fully delignified OPT. As proven by IR-spectroscopy, thermogravimetry and chemical composition analysis, alkali-treated OPT fibrils still contained substantial amounts of residual lignin which could, for instance, act as a natural coupling agent or binder in composite applications. Moreover, the facile delignification process applied herein requires far less chemicals and energy than conventional pulping and is thus beneficial from both the economic and ecological perspective.
... Xylans are hydrophilic polymers; and the poor hydrophobic properties limit their applications as emulsifiers (Falkeborg and Guo 2015;Laine et al. 2013). To improve the amphipathic properties, many efforts have been devoted to the chemical modification of xylans; such as oxidation, esterification, etherification, and cross-linking (Alekhina et al. 2014;Amer et al. 2016;Bigand et al. 2011;Daus et al. 2010;Farhat et al. 2017;Junli et al. 2012;Konduri and Fatehi 2016). ...
Hemicellulose, which is an abundant polysaccharide, has the potential to be an alternative for petroleum-based emulsifiers. In this study, dodecenyl succinic anhydride (DDSA) modified glucuronoxylans (DDSA-GLX) with high degree of substitution (DS) were synthesized through homogeneous esterification. The emulsifying properties of DDSA-GLX were investigated. The influences of pH, DS, calcium and sodium ions, and solvent system on the emulsifying properties (droplet size, zeta potential, emulsifying activity, and emulsion stability) were evaluated. The results indicated that the DS hold positive impact on the emulsifying properties of DDSA-GLX. With the increasing of DS, DDSA-GLX emulsions showed smaller droplet size (~ 0.56 μm), lower zeta potential (− 27.6 mV), higher emulsifying activity (0.989), and better emulsion stability. In addition, DDSA-GLX showed better emulsifying properties at pH 6.5 and pH 8.5. Calcium and sodium ions had negative impacts on the emulsifying properties of DDSA-GLX. Furthermore, DDSA-GLX prepared in water showed better emulsifying properties than those of DDSA-GLX prepared in DMSO (DS = 0.044). To sum up, the DDSA-GLX with high DS (up to 0.328) presented satisfactory emulsifying properties and the potential to be an alternative for petroleum-based emulsifiers.
... Barrier films made from materials derived from lignocellulosic feedstock such as wood hemicelluloses would constitute an environmentally sustainable alternative to commercial plastic barrier films manufactured from petrochemicals. Xylan and GGM extracted from bleached kraft pulps have previously been etherified with epoxy-functional ethers (propylene oxide, allyl glycidyl ether and/or butyl glycidyl ether) to plasticise them and render them suitable for coatings, films or hydrogels [5][6][7][8][9]. The partial etherification of hemicellulose hydroxyl groups yielded xylan and GGM ethers differing in their hydrophobicity, side-chain length and structure, and degree of substitution. ...
... New peaks, assigned to the methyl and methylene carbons not directly bonded to oxygen in the 3-butoxy-2-hydroxypropyl chain, appeared in the quantitative CP/MAS solidstate 13 C NMR spectrum of the product (Figure 2). Its degree of substitution (no. of etherified pyranose hydroxyls per pyranose unit) was calculated as 0.5 based on the butyl methylene and methyl peaks and the pyranose anomeric C1 peak, similar to those obtained for xylan under similar reaction conditions [5]. The acetyl peaks from hemicellulose were eliminated, indicating that acetyl groups were fully hydrolysed in the course of the reaction, which was carried out at highly alkaline conditions. ...
... New peaks, assigned to the methyl and methylene carbons not directly bonded to oxygen in the 3-butoxy-2-hydroxypropyl chain, appeared in the quantitative CP/MAS solid-state 13 C NMR spectrum of the product (Figure 2). Its degree of substitution (no. of etherified pyranose hydroxyls per pyranose unit) was calculated as 0.5 based on the butyl methylene and methyl peaks and the pyranose anomeric C1 peak, similar to those obtained for xylan under similar reaction conditions [5]. The acetyl peaks from hemicellulose were eliminated, indicating that acetyl groups were fully hydrolysed in the course of the reaction, which was carried out at highly alkaline conditions. ...
Citation: Widsten, P.; Murton, K.; Bowers, T.; Bridson, J.; Thumm, A.; Hill, S.; Tutt, K.; West, M.; Weinberg, G.; Durbin, G.; et al. Pilot-Scale Production of Hemicellulose Ethers from Softwood Hemicelluloses Obtained from Compression Screw Pressate of a Thermo-Mechanical Pulping Plant. Polymers 2023, 15, 2376. https://doi. Abstract: Bio-derived materials are becoming increasingly sought-after as a sustainable alternative to petrochemical-derived polymers. In the present pilot-scale study, a hemicellulose-rich compression screw pressate, obtained from the pre-heating stage of thermo-mechanical pulping (TMP) of radiata pine, was purified by treatment with adsorbent resin (XAD7), then ultrafiltered and diafil-tered at 10 kDa to isolate the high-molecular weight (MW) hemicellulose fraction (yield 18.4% on pressate solids), and, finally, reacted with butyl glycidyl ether to plasticise the hemicelluloses. The resulting light brown hemicellulose ethers (yield 102% on the isolated hemicelluloses) contained ca. 0.5 butoxy-hydroxypropyl side chains per pyranose unit and had weight-and number-average MWs of 13,000 Da and 7200 Da, respectively. The hemicellulose ethers may serve as raw material for bio-based products such as barrier films.
... This growth is primarily based on the environmental need to place synthetic polymers and to produce sustainable and biocompatible packaging terials [34][35][36]. To broaden hemicellulose applications, a variety of chemical reactions for its fu tionalization have been reported, such as oxidation, reduction, esterification (i.e., ac lation, propionylation, oleoylation, lauroylation, benzolation or crosslinking) or ethe cation (i.e., cationization, carboxymethylation or alkoxylation) [37][38][39][40][41][42][43]. ...
... The modification methods with low environmental impacts and th effects on the properties of hemicelluloses will be presented while keeping in mind b the quality performances of obtained derivatives and their practical applications. To broaden hemicellulose applications, a variety of chemical reactions for its functionalization have been reported, such as oxidation, reduction, esterification (i.e., acetylation, propionylation, oleoylation, lauroylation, benzolation or crosslinking) or etherification (i.e., cationization, carboxymethylation or alkoxylation) [37][38][39][40][41][42][43]. ...
... Esterification is the most commonly method used for the chemical modification of hemicelluloses, and many studies on acetylated xylan have been published [50][51][52]. The reaction of xylan with propylene oxide and then acetylated, butylated, or allylated hydroxypropyl xylan are other reported approaches [37,53,54]. ...
Based on the environmental concerns, the utilisation of hemicelluloses in food packaging has become a sustainable alternative to synthetic polymers and an important method for the efficient utilisation of biomass resources. After cellulose, hemicellulose is a second component of agricultural and forestry biomass that is being taken advantage of given its abundant source, biodegradability, nontoxicity and good biocompatibility. However, due to its special molecular structure and physical and chemical characteristics, the mechanical and barrier properties of hemicellulose films and coatings are not sufficient for food packaging applications and modification for performance enhancement is needed. Even though there are many studies on improving the hydrophobic properties of hemicelluloses, most do not meet environmental requirements and the chemical modification of these biopolymers is still a challenge. The present review examines emerging and green alternatives to acetylation for xylan hemicellulose in order to improve its performance, especially when it is used as biopolymer in paper coatings or films for food packaging. Ionic liquids (ILs) and enzymatic modification are environmentally friendly methods used to obtain xylan derivatives with improved thermal and mechanical properties as well as hydrophobic performances that are very important for food packaging materials. Once these novel and green methodologies of hemicellulose modifications become well understood and with validated results, their production on an industrial scale could be implemented. This paper will extend the area of hemicellulose applications and lead to the implementation of a sustainable alternative to petroleum-based products that will decrease the environmental impact of packaging materials.
... A film made of poly(vinyl alcohol) (PVA) has a tensile strength of 180 MPa (Mohamed et al. 2017), while the film made from spruce xylans has a tensile strength of 55 MPa (Escalante et al. 2012). Consequently, the chemical modification such as acetylation (de Carvalho et al. 2020), hydroxyalkylation (Laine et al. 2013), grafting (Peng et al. 2015;Zhang et al. 2015) and crosslinking (Yang et al. 2019) are usually applied to improve the film formability and film mechanical properties of xylans for their better utilizations. However, chemical modifications have the problems of high costs and toxic chemicals and thus the utilization of unmodified xylans is more proposed for the industrial application of xylans. ...
The most promising application of xylans is as coating agents. The basis of a xylan coating is to form a water cast film on a substrate, and the performance of the film would affect the quality of coatings. The film formability and film mechanical properties of xylans greatly depend on the plant sources, isolation methods and the crystallization of xylans, but general rules have not been systematically summarized. In this study, sequential alkali extraction and graded ethanol precipitation methods were used to extract xylans from birchwood or its holocelluloses to obtain xylans with different chemical structures. The effects of chemical structures on the crystallization property and film formability of birchwood xylans were investigated. Different from the arabinose side chains in bagasse xylans, glucuronic acid side chains do not affect the crystallinity of birchwood xylans simply by the degree of substitution. The carboxyls of glucuronic acid shifting between salt/acid forms exert unique effects on the crystallinity of xylans. Excessive aggregation of xylan molecules resulting in high residual compressive stresses is the cause for inferior film formability. Lignin can act as an impurity to prevent xylan aggregation and high lignin content would be beneficial to the xylan film formation.
... The esterification is the most frequently used method for chemical modification, and many studies on acetylated xylan have been published [22][23][24]. The reaction of xylan with propylene oxide and then acetylated, butylated, or allylated hydroxypropyl xylan are other reported approaches [25][26][27]. ...
In order to improve the hydrophobicity of xylan hemicellulose, a simple procedure of its chemical modification with alkyl ketene dimer (AKD), a non-toxic, cost-effective, and eco-friendly chemical, was performed. For this purpose, the reaction products of beech wood xylan and different amounts of hydrophobic AKD were used for paper surface treatment. Thus, the coatings of about 4.5 g/m2 were applied on both sides of base paper in single and three successive layers. To obtain a complete reaction between AKD and xylan hemicellulose, the coated papers were thermal cured (about 110 °C) and the effects of AKD content on the barrier (water, oil, and water vapours) and mechanical properties were analysed. The structural analyses by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR) of coated samples emphasized the presence of β-keto-ester compounds as a result of the reaction between xylan hemicelluloses and AKD. This is confirmed by the improving of barrier properties as the AKD content in coating dispersion is higher. The good barrier performance and improved strength properties were obtained for the coated papers with xylan hemicellulose and 1% AKD applied on paper surface in three successive layers (about 4.5 g/m2). In this case, the water vapours transmission rate (WVTR) was 35% lower than those untreated and the resistance to air passing through coated papers was over 3 times higher compared with base paper. There are no results reported on the chemical reaction of xylan hemicelluloses with AKD as well as its application in coatings for paper packaging. In this context, the obtained results in this study can contribute to expand the applications area of hemicelluloses offering a sustainable strategy for the developing of food packaging papers with appropriate barrier properties using biopolymer coating materials.
... At various temperatures and pressures, food components undergo phase changes during preparation and storage (liquid-gel or liquid-solid). These changes have an effect on food quality and consistency (Laine et al., 2013). This is because phase transitions in food components are linked to changes in the physical properties of meals. ...
An expeditious pace of expanding industrialization and urbanization is a global vulnerability which immediately requires utmost attention towards the replacement of prosaic petroleum-based polymer assimilation. Thus, greening the innovative route of microalgae derived biopolymers has attained significant interest as an improved and sustainable approach towards the worldwide circular bioeconomy. In this context, the use of as synthesized biopolymers from microalgae attributing as a potential feedstock has bestowed for a biodegradable solution to reduce the greenhouse gases emission and rapid biomass productivity with metabolic flexibility. However, the confront of high microalgae cultivation cost and low metabolites’ accumulation have triggered the advancement of microalgae metabolic cultivation strategy. Hence, the current review portrays to propose a novel multi-phasic fed batch light depleted low-cost wastewater cultivation approach and a clear mechanistic phenomenon for accelerating the biopolymer production. This review also provides a comprehensive summary on several microalgae strains which are capable for biopolymer synthesis and various effective extraction techniques to isolate the biopolymers. The future endeavour and challenges on the microalgae circular bioeconomy which involves the current issues regarding the cell harvesting method, scale up and bioprocessing cost of microalgae cultivation have been highlighted. The applications for microalgae derived biopolymer in industrial and nutraceutical sectors have also been emphasized. This review is expected to bring new insights to the industrial stakeholders for further advancement of microalgae-based biopolymer field economically, and eventually contributing towards environmental sustainability.
... Globally, search of different polymers from natural resources is carried out by researchers and different environmental agencies. Apart from the hazardous problem, the raw materials for synthetic polymers are also non-renewable sources like petrochemicals (Farris et al. 2009;Laine et al. 2013). Therefore, the biobased products including biopolymers have been foreseen as substitute for chemical-based macromolecules (Cutter 2006;Satyanarayana et al. 2009). ...
The advent of Second Green Revolution for nutritional security to feed the burgeoning world population amidst the challenges is related to climate change, resource availability, and farmers’ income. In this scenario, the next-generation breeding technology or genome editing (GE) technique is promising and gaining wider acceptance and importance for improving economically important traits in crops. The meganucleases, zinc-finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR) are important tools of GE. Among these, CRISPR is the most recent tool and revolutionizing the field of crop improvement. Advancements in the basic CRISPR/Cas system made it a more accurate, precise, and versatile tool. At present, a variety of genome-edited crops are available at different parts of the world, which are approved for cultivation. In this book chapter, we have mainly discussed about available genome-edited food crops and ongoing GE research work on food crops including cereals, horticultural and futuristic crops for specific traits. We have also presented an overview of the advancement in GE technique, regulation of GE food crops, and scope of GE in futuristic crops.KeywordsNew breeding techniqueGenome editingCRISPR/CasBase editingFood securityFuturistic cropsClimate change
... Globally, search of different polymers from natural resources is carried out by researchers and different environmental agencies. Apart from the hazardous problem, the raw materials for synthetic polymers are also non-renewable sources like petrochemicals (Farris et al. 2009;Laine et al. 2013). Therefore, the biobased products including biopolymers have been foreseen as substitute for chemical-based macromolecules (Cutter 2006;Satyanarayana et al. 2009). ...
Bio/micro and nanoencapsulation technologies have developed as a potential strategy for delivering and preserving bioactive nutrients. Micro- and nanoencapsulation technologies might enhance the flavor, texture, consistency, and taste of the food products. The antimicrobial ability of the encapsulated materials provides stability and usable ability in food packaging materials, thereby enhancing the shelf life of the food products as well as safer for human utilization. The rate release of the compounds might be controlled by using encapsulation, thereby maintaining the flavor and sweetness of the food product. This book chapter focuses on the encapsulation of bioactive compounds and its importance in food science, synthesis of bio, micro, and nano-encapsulation techniques, carrier agents used in micro and nano-encapsulation, technological aspects, and safety aspect.KeywordsEncapsulationFoodNutrientsBio-active compoundNanotechnology
... Globally, search of different polymers from natural resources is carried out by researchers and different environmental agencies. Apart from the hazardous problem, the raw materials for synthetic polymers are also non-renewable sources like petrochemicals (Farris et al. 2009;Laine et al. 2013). Therefore, the biobased products including biopolymers have been foreseen as substitute for chemical-based macromolecules (Cutter 2006;Satyanarayana et al. 2009). ...
Polymers have become an irreplaceable part in countless living applications. With rapid technology shift and focus on the food industries, the demand of synthetic polymers has significantly increased. However, the recalcitrant nature and its associated ecological problems have led the researchers to substitute the synthetic polymer with bio-based polymers. Biocompatible and biodegradable properties make biopolymers commercially important and sustainable. Among the different classes of biopolymers, the microbial polysaccharides are vital for food industry. Microbial polymers like celluloses, gums, pectin, starch, agar, and alginates have gained significant attention in food industries as these polysaccharides are used as composite materials in manufacturing of industrial product like hydrogels, nanoparticles, and micelles. The advantage of easy manipulation, easy availability of raw material, and low cost makes them ideal industrial candidate for high commercial production. The present chapter focuses on the different microbe-based biopolymers and its application in food industry.
