Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Small ; : e2403781, 2024 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-38850188

RESUMO

The delayed healing of infected wounds can be attributed to the increased production of reactive oxygen species (ROS) and consequent damages to vascellum and tissue, resulting in a hypoxic wound environment that further exacerbates inflammation. Current clinical treatments including hyperbaric oxygen therapy and antibiotic treatment fail to provide sustained oxygenation and drug-free resistance to infection. To propose a dynamic oxygen regulation strategy, this study develops a composite hydrogel with ROS-scavenging system and oxygen-releasing microspheres in the wound dressing. The hydrogel itself reduces cellular damage by removing ROS derived from immune cells. Simultaneously, the sustained release of oxygen from microspheres improves cell survival and migration in hypoxic environments, promoting angiogenesis and collagen regeneration. The combination of ROS scavenging and oxygenation enables the wound dressing to achieve drug-free anti-infection through activating immune modulation, inhibiting the secretion of pro-inflammatory cytokines interleukin-6, and promoting tissue regeneration in both acute and infected wounds of rat skins. Thus, the composite hydrogel dressing proposed in this work shows great potential for dynamic redox regulation of infected wounds and accelerates wound healing without drugs.

2.
J Sci Food Agric ; 104(9): 5565-5576, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38372364

RESUMO

BACKGROUND: Distiller's grains (DGs), which are rich in natural ingredients such as prolamins, are often used as low-value feed or discarded directly, resulting in great environmental pollution and resource waste. Prolamins from DGs (PDGs) were found to be a potential material for the construction of biopolymer films due to their good film-forming properties. In this study, extrusion processing was conducted to modify the physicochemical and structural properties of PDGs to facilitate the construction of biopolymer films with superior characteristics. RESULTS: Results indicated that extrusion led to improved solubility (17.91% to 39.95%) and increased disulfide bonds (1.46 to 6.13 µmol g-1) in PDGs. The total and sulfur amino acid contents of extruded PDGs were increased by 13.26% and 38.83%, respectively. New aggregation patterns were formed after extrusion according to the results of scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. Extrusion resulted in reduced surface hydrophobicity of PDGs (10 972 to 3632), sufficient evidence for which could be also found from structure analyses of PDGs. Finally, PDGs extruded at 110 °C were found to facilitate the forming of biopolymer films with superior mechanical properties, water resistance and thermal stability. CONCLUSIONS: Physicochemical and structural properties of PDGs were effectively modified by extrusion processing, and extrusion modification of PDGs could be a great way to facilitate the construction of biopolymer films with superior characteristics. It could provide more possibilities to extend the applications of DGs to alleviate the problems of environmental pollution and resource waste. © 2024 Society of Chemical Industry.


Assuntos
Prolaminas , Solubilidade , Biopolímeros/química , Prolaminas/química , Grão Comestível/química , Interações Hidrofóbicas e Hidrofílicas , Espectroscopia de Infravermelho com Transformada de Fourier , Difração de Raios X , Resistência à Tração
3.
J Sci Food Agric ; 103(12): 5811-5818, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37092328

RESUMO

BACKGROUND: Potato protein possesses strong potential for application in the food industry due to its outstanding nutritional and functional properties. However, the inevitable industrial processing often brings adverse effects. The use of a polysaccharide and protein complex is a promising way to improve the performance of potato protein. This work aimed to investigate the effects of different physical factors on the potato protein/chitosan (PP/CS) complex system. RESULTS: The addition of NaCl was not conductive to the formation of PP/CS complexes, resulting in significantly decreased peak turbidities from 1.29 to 0.75. The effect of different ions on PP/CS system matched with the Hofmeister series in the following order: Li+ > Control > Na+ > K+ ; SCN- > I- > NO3 - > Br- ≈ Control > Cl- > SO4 2- , among which the salting-in ions (Li+ , Br- , NO3 - , I- and SCN- ) tended to promote the formation of PP/CS complexes. The turbidity increased significantly when the reaction temperature rose to 45 °C and above, and peak turbidity was obtained at lower pH values. The PP/CS system reaction at 45 °C led to the highest whiteness value, and the Maillard reaction could occur when the temperature was above 45 °C. CONCLUSIONS: The results of the present study confirmed that different physical factors led to strong influences on PP/CS complexes, especially when considering the Hofmeister series and the Maillard reaction. These findings could have significant implications for the utilization of potato protein in complex food systems. © 2023 Society of Chemical Industry.


Assuntos
Quitosana , Solanum tuberosum , Quitosana/química , Reação de Maillard , Solanum tuberosum/química , Temperatura , Íons , Cloreto de Sódio
4.
Plant Foods Hum Nutr ; 76(1): 26-30, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33247389

RESUMO

Pea flour was extruded at 50, 70, and 90 °C. The in vitro digestibility and characteristics of native and extruded pea flour were investigated. The in vitro starch digestibility (IVSD) and in vitro protein digestibility (IVPD) of the extruded pea flour were higher than those of the native pea flour and increased with increasing extrusion temperature from 50 to 90 °C. The rapidly digestible starch increased to 28.34% at 90 °C, the highest slowly digestible starch (SDS) content was 22.70% at 50 °C, and resistant starch content decreased to 4.71% at 90 °C. The IVPD increased from 80.94% relative to the native pea flour to 90.21% at 90 °C. Improved swelling power enabled the extruded pea flour to exhibit better performance and higher breakdown viscosity and lower setback viscosity than the native pea flour demonstrated that extrusion reduced the thermal stability and retrogradation tendency. Increasing extrusion temperatures greatly reduced the relative crystallinity (based on X-ray diffraction analysis) from 32.69% relative to the native pea flour to 9.76% at 90 °C. Extrusion treatment also reduced ß-sheet content (based on Fourier transform infrared spectroscopy analysis) from 36.40% relative to the native pea flour to 31.79% at 90 °C. IVPD and IVSD improved, and the SDS content increased at 50 °C and 70 °C, thereby indicating that extruded pea flour can be applied to healthy food products.


Assuntos
Farinha , Pisum sativum , Farinha/análise , Manipulação de Alimentos , Amido , Temperatura , Viscosidade
5.
J Sci Food Agric ; 100(7): 2866-2872, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31960976

RESUMO

BACKGROUND: Potato protein (PP) has promising potential for utilization in food applications due to its high nutritive value and functional properties. Grapeseed oil (GO) is rich in unsaturated fatty acids and antioxidant active ingredients. However, its application is limited because of low stability and high volatility. In order to overcome such problems, PP-based microcapsules encapsulating GO were produced by complex coacervation, and characterized using optical, thermodynamic and spectroscopic analyses. RESULTS: Results indicated that a ratio of GO/PP of 1:2 led to the best encapsulation effect with the maximum microencapsulation efficiency and yield. Intact and nearly spherical microcapsules were observed from scanning electron microscopy images. Results of thermogravimetry demonstrated that thermal resistance was increased in the microencapsulated GO, indicating that PP-based microcapsules could be a good way to protect the thermal stability of GO. Fourier transform infrared spectra indicated that hydrogen bonding and covalent crosslinking might occur among wall materials, but a physical interaction between GO and wall materials. CONCLUSIONS: PP can be successfully used to encapsulate GO when combined with chitosan, indicating that PP-based microcapsules have potential for application in encapsulating liquid oils with functional properties. A schematic diagram of possible interactions was constructed to better understand the mechanism of formation of the microcapsules. © 2020 Society of Chemical Industry.


Assuntos
Cápsulas/química , Composição de Medicamentos/métodos , Óleos de Plantas/química , Proteínas de Plantas/química , Quitosana/química , Extrato de Sementes de Uva/química , Solanum tuberosum
6.
J Food Sci Technol ; 57(2): 734-744, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-32116382

RESUMO

ABSTRACT: Edible chitosan film incorporated with rutin-ß-cyclodextrin was developed and characterized. The delivery of rutin was improved via the hydrolyzation function of glucoamylase, and the antioxidant activity of the chitosan film was enhanced by the addition of rutin. Sodium bicarbonate solution at different pHs (pH-adjusting reagent) was employed to afford the mild condition for the incorporated glucoamylase. The enzyme exhibited its hydrolyzation function to improve the release rate of rutin by destabilizing the rutin-ß-cyclodextrin complex (RCC) in chitosan film. The optimum pH of glucoamylase was achieved with 5 mL addition amount of 0.5 mol/L sodium bicarbonate solution, and the glucoamylase improved the radical scavenging ratio of chitosan film. The yellowness of chitosan film was enhanced with the addition of RCC solution. The films prepared without water demonstrated coarse and rough surface, while the water-based films had smoother and even surface as examined by scanning electron microscopy. In contrast, these observations disappeared in the water immersion groups. X-ray diffraction suggested that the hydrolyzation of ß-cyclodextrin and the interlinkage between ß-cyclodextrin and the chitosan chain exerted a negative function on maintaining the crystal structure of pure chitosan film. Further, the destabilization of RCC complex with the glucoamylase activity was evidenced by the absence of peak associated with ß-cyclodextrin as observed from Fourier transform infrared spectra. The enzyme improved the release of rutin and the addition of RCC successfully endowed antioxidant activity to the chitosan film.

7.
Int J Biol Macromol ; 264(Pt 2): 130702, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38471607

RESUMO

Pretreatment is a key process restricting the development of biorefinery. This work developed a pretreatment process based on an ethanolamine/acetamide alkaline deep eutectic solvent (ADES). Under microwave assistance, pure ADES pretreatment at 100 °C for 10 min achieved 95.9 % delignification and 95.2 % hemicellulose removal of bamboo shoot shells (BSS). Further, when 75 % water was added to pure DES to prepare hydrated DES (75 %-HADES), impressive delignification (93.2 %), hemicellulose removal (92.2 %) and cellulose recovery (94.8 %) were still achieved. The cellulose digestibility of the 75 %-HADES pretreated solid residue was significantly increased from 12.2 % (the control) to 91.2 %. Meanwhile, the structural features of hemicellulose and lignin macromolecules fractionated by 75 %-HADES pretreatment were well preserved, offering opportunities for downstream utilization. Overall, this work proposes an effective pretreatment strategy with the potential to enable the utilization of all major components of bamboo shoot shells.


Assuntos
Celulose , Solventes Eutéticos Profundos , Solventes/química , Biomassa , Hidrólise , Lignina/química
8.
Int J Biol Macromol ; 235: 123688, 2023 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-36801284

RESUMO

To comprehend the biosynthesis processes of conifers, it is essential to investigate the disparity between the cell wall shape and the interior chemical structures of polymers throughout the development of Chinese pine. In this study, branches of mature Chinese pine were separated according to their growth time (2, 4, 6, 8 and 10 years). The variation of cell wall morphology and lignin distribution was comprehensively monitored by scanning electron microscopy (SEM) and confocal Raman microscopy (CRM), respectively. Moreover, the chemical structures of lignin and alkali-extracted hemicelluloses were extensively characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The thickness of latewood cell walls increased steadily from 1.29 µm to 3.38 µm, and the structure of the cell wall components became more complicated as the growth time increased. Based on the structural analysis, it was found that the content of ß-O-4 (39.88-45.44/100 Ar), ß-ß (3.20-10.02/100 Ar) and ß-5 (8.09-15.35/100 Ar) linkages as well as the degree of polymerization of lignin increased with the growth time. The complication propensity increased significantly over 6 years before slowing to a trickle over 8 and 10 years. Furthermore, alkali-extracted hemicelluloses of Chinese pine mainly consist of galactoglucomannans and arabinoglucuronxylan, in which the relative content of galactoglucomannans increased with the growth of the pine, especially from 6 to 10 years.


Assuntos
Parede Celular , Lignina , Pinus , Polissacarídeos , Lignina/química , Pinus/química , Pinus/crescimento & desenvolvimento , Polissacarídeos/química , Parede Celular/química , Parede Celular/metabolismo
9.
Bioresour Technol ; 387: 129679, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37579860

RESUMO

In this study, light-colored lignin was extracted from bamboo shoot shells (BSS) using a hydrated deep eutectic solvent (DES) pretreatment. The hydrated DES used in pretreatment consist of formic acid, benzyl triethylammonium chloride (BTEAC) and water. The pretreatment using a hydrated DES containing 30% water (H30) demonstrate efficient delignification (82.9%). Additionally, the hydrated DES protected the ß-O-4 linkage from excessive cleavage and recondensation as well as keep the light-colored of lignin. Moreover, the hydrated DES extracted lignin exhibits superior antioxidant performance and tyrosinase inhibitory capacity compared to the control. Notably, incorporating 5% lignin of H30-extracted lignin into a commercial suncream led to a remarkable enhancement of the SPF value, elevating from 14.8 to 32.6. In summary, the proposed hydrated DES pretreatment method offers significant benefits for extracting light-colored lignin, thereby promoting the multifunctional application of lignin in cosmetics.


Assuntos
Solventes Eutéticos Profundos , Lignina , Solventes , Biomassa , Água , Hidrólise
10.
Int J Biol Macromol ; 253(Pt 2): 126840, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37696374

RESUMO

The interactions between potato starch (PtS) and barley ß-glucan (BBG) were investigated by preparing PtS-BBG mixtures, and the pasting, rheological, gelling and structural properties were evaluated. Rapid viscosity analysis suggested that BBG reduced the peak and breakdown viscosity, while increasing the setback viscosity of PtS. PtS-12%BBG showed the lowest leached amylose content (12.02 ± 0.36 %). The particle size distribution pattern of PtS was not changed with the addition of BBG, and the median diameter of PtS-12%BBG (88.21 ± 0.41 µm) was smaller than that of PtS (108.10 ± 6.26 µm). Rheological results showed that PtS and PtS-BBG gels exhibited weak gel behaviors, and BBG could remarkably affect the elastic and viscous modulus of PtS gels. Textural analysis suggested that the strength and hardness of PtS gels were increased when few BBG (<6 %, w/w) was present in the system. BBG improved the freeze-thaw stability of PtS gels. Structural analysis indicated that hydrogen bonds were the main force in the PtS-BBG systems. These results indicated that BBG interacted with starch via hydrogen bonds, which delayed starch gelatinization and improved gelling properties of PtS gels. Overall, this study gained insights into starch-polysaccharide interactions and revealed the possible applications of BBG in food processing.


Assuntos
Hordeum , Solanum tuberosum , beta-Glucanas , Amido/química , Géis/química , Viscosidade , Reologia
11.
J Food Sci ; 88(7): 2833-2844, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37219380

RESUMO

The influences of barley ß-glucan (BBG) on the physicochemical properties and in vitro digestibility of pea starch were investigated. BBG was found to decrease pasting viscosity in a concentration dependent manner and inhibited the aggregation of pea starch. After the presence of BBG, the gelatinization enthalpy of pea starch was decreased (from 7.83 ± 0.03 to 5.55 ± 0.22 J/g), whereas the gelatinization temperature was enhanced (from 62.64 ± 0.01 to 64.52 ± 0.14°C) according to the differential scanning calorimeter results. In addition, BBG inhibited the swelling of pea starch and amylose leaching. When amylose leached out from pea starch to form a BBG-amylose barrier, starch gelatinization was inhibited. The starch gels exhibited weak gels and shear thinning behaviors by rheological tests results. The interaction between BBG and amylose led to lower viscoelasticity and texture parameters in pea starch gels. The structure analysis results unveiled that the force between BBG and amylose was mainly hydrogen bonds. Pea starch hydrolysis was inhibited when BBG was present in the system, which was connected with the restricted starch gelatinization. These results obtained in the study would supply insights into incorporating BBG into various food systems.


Assuntos
Hordeum , beta-Glucanas , Amido/química , Amilose/química , Pisum sativum/química , Géis , Viscosidade
12.
Food Chem ; 424: 136441, 2023 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-37244182

RESUMO

Aflatoxin contamination in peanut kernels seriously harms the health of humans and causes significant economic losses. Rapid and accurate detection of aflatoxin is necessary to minimize its contamination. However, current detection methods are time-consuming, expensive and destructive to samples. Therefore, short-wave infrared (SWIR) hyperspectral imaging coupled with multivariate statistical analysis was used to investigate the spatio-temporal distribution patterns of aflatoxin, and quantitatively detect the aflatoxin B1 (AFB1) and total aflatoxin in peanut kernels. In addition, Aspergillus flavus contamination was identified to prevent the production of aflatoxin. The result of validation set demonstrated that SWIR hyperspectral imaging could predict the contents of the AFB1 and total aflatoxin accurately, with residual prediction deviation values of 2.7959 and 2.7274, and limits of detection of 29.3722 and 45.7429 µg/kg, respectively. This study presents a novel method for the quantitative detection of aflatoxin and offers an early warning system for its potential application.


Assuntos
Aflatoxinas , Humanos , Aflatoxinas/análise , Aflatoxina B1/análise , Arachis , Imageamento Hiperespectral , Contaminação de Alimentos/análise , Aspergillus flavus
13.
Int J Biol Macromol ; 253(Pt 4): 127029, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37742903

RESUMO

Effective separation of lignin macromolecules from the xylose pre-hydrolysates (XPH) during the xylose production, thus optimizing the separation and purification process of xylose, is of great significance for reducing the production costs, achieving the high value-added utilization of lignin and increasing the industrial revenue. In this study, a simple and robust method (pH adjustment) for the separation of lignin from XPH was proposed and systematically compared with the conventional acid-promoted lignin precipitation method. The results showed that the lignin removal ratio (up to 60.34 %) of this simple method was higher than that of the conventional method, and the proposed method eliminated the necessity of heating and specialized equipment, which greatly reduced the separation cost. Meanwhile, this simple method does not destroy the components in XPH (especially xylose), ensuring the yield of the target product. On the other hand, the obtained lignin was nano-scale with less condensed structures, which also possessed small molecular weights with narrow distribution, excellent antioxidant activity (8-14 times higher than commercial antioxidants) and UV protection properties. In conclusion, the proposed simple separation method could effectively separate lignin from XPH at low cost, and the obtained lignin had potential commercial applications, which would further enhance the overall profitability of industrial production.


Assuntos
Lignina , Xilose , Lignina/química , Xilose/química , Hidrólise , Bebidas Alcoólicas
14.
Bioresour Technol ; 385: 129415, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37390929

RESUMO

In this work, a green and robust pretreatment which integrated acetic acid-catalyzed hydrothermal and wet mechanical pretreatment, was developed to efficiently produce high yield (up to 40.12%) of xylooligosaccharides and digestible substrates from Caffeoyl Shikimate Esterase down-regulated and control poplar wood. Subsequently, superhigh yield (more than 95%) of glucose and residual lignin were obtained after a moderate enzymatic hydrolysis. The residual lignin fraction exhibited a well-preserved ß-O-4 linkages (42.06/100Ar) and high S/G ratio (6.42). Subsequently, lignin-derived porous carbon was successfully synthesized, and it exhibited a high specific capacitance of 273.8 F g-1 at 1.0 A g-1 and long cycling stability (remained 98.5% after 10,000 cycles at 5.0 A g-1) compared to control poplar wood, demonstrating that special advantage of this genetically-modified poplar in this integrated process. This work developed an energy-saving and eco-friendly pretreatment technology as a waste-free route for converting different lignocellulosic biomass to multiple products.


Assuntos
Esterases , Lignina , Hidrólise , Madeira
15.
Int J Mol Sci ; 13(6): 7483-7495, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22837706

RESUMO

The process parameters of enzymatic hydrolysis and molecular weight distribution of glutamine (Gln) peptides from soybean meal were investigated. The Protamex(®) hydrolysis pH of 6.10, temperature of 56.78 °C, enzyme to substrate ratio (E/S) of 1.90 and hydrolysis time of 10.72 h were found to be the optimal conditions by response surface methodology (RSM) for a maximal degree of hydrolysis (DH) value of 16.63% and Gln peptides content at 5.95 mmol/L. The soybean meal was hydrolyzed by a combination of Protamex(®) and trypsinase so that DH and Gln peptides would reach 22.02% and 6.05 mmol/mL, respectively. The results of size exclusion chromatography indicated that the relative proportion of the molecular weight <1000 Da fraction increased with DH values from 6.76%, 11.13%, 17.89% to 22.02%, most notably the 132-500 Da fractions of hydrolysates were 42.14%, 46.57%, 58.44% and 69.65%. High DH values did not lead to high Gln peptides content of the hydrolysate but to the low molecular weight Gln peptides.


Assuntos
Glutamina/química , Glycine max/química , Peptídeos/química , Hidrolisados de Proteína/química , Proteínas de Soja/química
16.
J Food Sci ; 87(3): 1184-1196, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35122248

RESUMO

Microencapsulated procyanidins by extruding starch (MPS) were used in meat and meat products as an antioxidant for their simple production process and high stability. This study investigated the controlled released properties of MPS and their effect on antioxidant capacity, physicochemical properties, and sensory qualities of chicken sausages during 4°C storage within 28 days. Antioxidant capacity, particle size analysis, and simulated digestion in vitro demonstrated that microencapsulation by extruding starch delayed the procyanidins release. The reduced crystal structure of MPS was determined by the morphology observation (SEM) and the decrease of the typical diffraction peak at 2θ of 20.9° (XRD). The MPS-added sausage had a higher (p < 0.05) ABTS and DPPH radical scavenging ratio (97.6% and 67.3%) and sulfhydryl contents (114.69 nmol/g protein) than other groups. Moreover, lower (p < 0.05) thiobarbituric acid reactive substances (TBARS) (0.67 mg MDA/kg sausage) and carbonyl values (3.24 nmol/mg protein) were detected in MPS-added sausages than others at the end of storage. The MPS addition increased redness (a* value) and decreased the lightness (L* value). The sensory analysis suggested that the sausage with the increased redness was favorable. These results denominated that MPS was an alternative antioxidant in chicken sausages. Practical Application: In this study, microencapsulated procyanidins were prepared by extrusion technology, and the effect on the quality of chicken sausages was investigated, which provides an alternative natural antioxidant for meat and meat products.


Assuntos
Produtos da Carne , Proantocianidinas , Animais , Galinhas , Lipídeos/química , Produtos da Carne/análise , Oxidantes , Amido
17.
Food Chem ; 390: 133187, 2022 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-35569400

RESUMO

Distiller's grains (DGs) possessed great potential utilization value due to their rich active ingredients. However, its utilization efficiency was limited by the large amount of lignocellulose components and water-insoluble proteins. In this work, single screw extrusion was applied to modify physicochemical properties of DGs. Results indicated that extruded distiller's grains (EDGs) exhibited the lower crude fiber content (26.01%), the higher soluble fiber (9.07%) and the smaller particle size when compared with those of Control, and subsequently achieving the increased bulk density, swelling capacity and water/oil holding capacity. The crude protein in EDGs decreased slightly, while the total amount of acid hydrolyzed amino acids showed a significant increase. Additionally, the looser, coarser and fragmentary microstructure of EDGs were observed. The main macromolecules in EDGs had been modified distinctly based on thermal analysis, crystallinity and functional groups analyses, while the possible schematic diagram was conducted to better understand the modification mechanism.


Assuntos
Aminoácidos , Grão Comestível , Aminoácidos/análise , Ração Animal/análise , Grão Comestível/química , Estruturas Vegetais/química , Proteínas/análise , Água/química
18.
Int J Biol Macromol ; 209(Pt B): 1882-1892, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35489620

RESUMO

Elucidating the structural variations of lignin during the pretreatment is very important for lignin valorization. Herein, poplar wood was pretreated with an integrated process, which was composed of AlCl3-catalyzed hydrothermal pretreatment (HTP, 130-150 °C, 1.0 h) and mild deep-eutectic solvents (DES, 100 °C, 10 min) delignification for recycling lignin fractions. Confocal Raman Microscopy (CRM) was developed to visually monitor the delignification process during the HTP-DES pretreatment. NMR characterizations (2D-HSQC and 31P NMR) and elemental analysis demonstrated that the lignin fractions had undergone the following structural changes, such as dehydration, depolymerization, condensation. Molecular weights (GPC), microstructure (SEM and TEM), and antioxidant activity (DPPH analysis) of the lignins revealed that the DES delignification resulted in homogeneous lignin fragments (1.32 < PDI < 1.58) and facilitated the rapid assemblage of lignin nanoparticles (LNPs) with controllable nanoscale sizes (30-210 nm) and excellent antioxidant activity. These findings will enhance the understanding of structural transformations of the lignin during the integrated process and maximize the lignin valorization in a current biorefinery process.


Assuntos
Lignina , Populus , Antioxidantes/farmacologia , Biomassa , Solventes Eutéticos Profundos , Hidrólise , Lignina/química , Solventes/química
19.
Bioresour Technol ; 352: 127065, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35351557

RESUMO

An aspirational pretreatment method for efficient fractionation and tailored valorization of large industrial biomass can ensure the realizability of sustainable biorefinery strategies. In this study, an ultrafast alkaline deep eutectic solvents (DES) pretreatment strategy was developed to efficiently extract the lignin nanoparticles and retain cellulose residues that could be readily enzymatic saccharified to obtain fermentative glucose for the bioenergy production from industrial xylose residue. Results showed that the DES pretreatment had excellent delignification performance and the regenerated DES lignin nanoparticles exhibited well-preserved structures and excellent antioxidant activity, as well as low molecular weights and relatively uniform size distribution, which could facilitate downstream catalytic degradation for production of chemicals and preparation of lignin-based materials. Under the optimal condition (DES pretreatment: 80 °C, 10 min; saccharification: 10 FPU/g, 5 wt%, 100 mg/g Tween 80), the glucose yield of 90.12% could be achieved, which was dramatically increased compared to raw materials.


Assuntos
Lignina , Xilose , Biomassa , Solventes Eutéticos Profundos , Glucose , Hidrólise , Lignina/química , Solventes/química
20.
Front Bioeng Biotechnol ; 9: 790539, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34869298

RESUMO

Elucidating the chemical and structural characteristics of hemicelluloses and lignin in the p-coumarate 3-hydroxylase (C3H) down-regulated poplar wood will be beneficial to the upstream gene validation and downstream biomass conversion of this kind of transgenic poplar. Herein, the representative hemicelluloses and lignin with unaltered structures were prepared from control (CK) and C3H down-regulated 84K poplars. Modern analytical techniques, such as 13C NMR, 2D-HSQC NMR, and gel chromatography (GPC), were performed to better delineate the structural changes of hemicelluloses and lignin caused by transgenesis. Results showed that both the hemicelluloses (H-CK and H-C3H) extracted from control and C3H down-regulated poplar wood have a chain backbone of (1→4)-ß-D-Xylan with 4-O-Me-α-D-GlcpA as side chain, and the branch degree of the H-C3H is higher than that of H-CK. With regarding to the lignin macromolecules, NMR results demonstrated that the syringyl/guaiacyl (S/G) ratio and dominant substructure ß-O-4 linkages in C3H down-regulated poplar were lower than those of control poplar wood. By contrast, native lignin from C3H down-regulated poplar wood exhibited higher contents of p-hydroxybenzoate (PB) and p-hydroxyphenyl (H) units. In short, C3H down-regulation resulted in the chemical and structural changes of the hemicelluloses and lignin in these poplar wood. The identified structures will facilitate the downstream utilization and applications of lignocellulosic materials in the biorefinery strategy. Furthermore, this study could provide some illuminating results for genetic breeding on the improvement of wood properties and efficient utilization of poplar wood.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA