The gelating and swelling mechanisms of the hydrogel formed from oxidized konjac glucomannan (OKGM) and chitosan (CS) were studied by Fourier transform infrared (FT IR) spectrometry. FT IR spectra illustrate that the ...The gelating and swelling mechanisms of the hydrogel formed from oxidized konjac glucomannan (OKGM) and chitosan (CS) were studied by Fourier transform infrared (FT IR) spectrometry. FT IR spectra illustrate that the interaction of polysaccharides forms the hydrogen bonds and interchain salt bonds and the dissociation of which dominates the swelling behavior in buffer solutions of different pH. The concentration of salt ion has effect on swelling behavior through the difference of salt ion concentration between in solution and in network of hydrogel, which causes penetrating pressure. Moreover, the Swelling degree and hydrogel strength could be modulated by varying conditions. It is indicated that the hydrogel has pH sensitive and salt ion sensitive properties. The prepared optimum condition selected by varying conditions is that r = 0.2; t =30 min; T p =343 K and I =1.6.展开更多
Three materials(agar,konjac glucomannan(KGM)andκ-carrageenan)were used to prepare ternary systems,i.e.,sol-gels and their dried composites conditioned at varied relative humidity(RH)(33%,54%and 75%).Combined methods,...Three materials(agar,konjac glucomannan(KGM)andκ-carrageenan)were used to prepare ternary systems,i.e.,sol-gels and their dried composites conditioned at varied relative humidity(RH)(33%,54%and 75%).Combined methods,e.g.,scanning electron microscopy,small-angle X-ray scattering,infrared spectroscopy(IR)and X-ray diffraction(XRD),were used to disclose howκ-carrageenan addition tailors the features of agar/KGM/κ-carrageenan ternary system.As affirmed by IR and XRD,the ternary systems withκ-carrageenan below 25%(agar/KGM/carrageenan,50:25:25,m/m)displayed proper component interactions,which increased the sol-gel transition temperature and the hardness of obtained gels.For instance,the ternary composites could show hardness about 3 to 4 times higher than that for binary counterpart.These gels were dehydrated to acquire ternary composites.Compared to agar/KGM composite,the ternary composites showed fewer crystallites and nanoscale orders,and newly-formed nanoscale structures from chain assembly.Such multi-scale structures,for composites withκ-carrageenan below 25%,showed weaker changes with RH,as revealed by especially morphologic and crystalline features.Consequently,the ternary composites with lessκ-carrageenan(below 25%)exhibited stabilized elongation at break and hydrophilicity at different RHs.This hints to us that agar/KGM/κ-carrageenan composite systems can display series applications with improved features,e.g.,increased sol-gel transition point.展开更多
The stability against various environmental stresses of the curcumin-loaded secondary and tertiary emulsions that was emulsified by whey protein isolate(WPI)and coated by chitosan(CHI),carboxymethyl konjac glucomannan...The stability against various environmental stresses of the curcumin-loaded secondary and tertiary emulsions that was emulsified by whey protein isolate(WPI)and coated by chitosan(CHI),carboxymethyl konjac glucomannan(CMKGM),or their combination through layer-by-layer assembly was investigated.Generally,the multilayered emulsions were destabilized in high Na Cl concentrations or medium p H that could interrupt the electrostatic interaction between the three polyelectrolytes or deprotonate CHI,indicating that electrostatic interaction played an important role in the stability of emulsions.Compared with the primary emulsion that was solely stabilized by WPI,extra coating with CHI and CMKGM generally increased the stability of the emulsion against repeated freezing-thawing,improved the retention of curcumin against heating,UV irradiation,and long-term storage,and the effects were more remarkable in the tertiary emulsion with CMKGM locating in the outmost layer.Since CMKGM has shown the colon-targeted delivery potency,the multilayered emulsions assembled by layer-by-layer deposition,especially the tertiary emulsion,could be used as an effective carrier for the targeted delivery of curcumin.展开更多
The simulation is carried out by employing the method of molecular dynamics with the single chain of konjac glucomannan (KGM) in vacuum as the structural model to discuss the factors that affect the single chain struc...The simulation is carried out by employing the method of molecular dynamics with the single chain of konjac glucomannan (KGM) in vacuum as the structural model to discuss the factors that affect the single chain structure, the dynamic structure of the chain and the acting forces that maintain the chain structure. The results show that the shape and stability of the chain are affected by the degree of polymerization. As for the KGM with high degree of polymerization, its chain presents random coiling state and its stability declines. Both before and after deacetylation in the process of dynamic motion, the chain of KGM presents random coiling state with periodic variation of extension and coil and demonstrates favorable flexibility, indicating acetyl is not the main factor that affects the shape of chain, whereas dihedral angle and static actions are respectively the key bonding and nonbonding acting forces that influence the single chain conformations in vacuum.展开更多
In order to improve the mechanical and water swelling properties of the chitosan(CS) film, a series of transparent films were prepared by blending 2%(weight) chitosan acetic acid solution with 1.5%(weight) carboxymeth...In order to improve the mechanical and water swelling properties of the chitosan(CS) film, a series of transparent films were prepared by blending 2%(weight) chitosan acetic acid solution with 1.5%(weight) carboxymethylated konjac glucomannan(CMKGM) aqueous solution according to predetermined ratio and drying at 30℃. The morphological structure, miscibility, thermal stability, mechanical properties, and swelling capacity of the blend films were studied by infrared (IR), X-ray diffraction(XRD), differential thermal analysis(DTA), scanning electron micrograph(SEM), and measurements of the mechanical properties and swelling properties. The results demonstrated that there was strong interaction and good miscibility between CS and CMKGM resulted from intermolecular hydrogen bonding and electrostatic force. The mechanical properties in dry state and wet state, thermostability, and water swelling properties of the blend films were obviously improved. The best values of the tensile strength in the dry and wet state achieved 89 MPa and 49 MPa,respectively, when the CMKGM content was 30%(weight). The CS/CMKGM blend films provided promising biomedical applications.展开更多
Konjac glucomannan (KGM) was crosslinked with sodium tripolyphosphate (STPP) to synthesize hydrogels. The crosslinking reaction was confirmed by FT-IR. The results of degradation test show that the hydrogels retain th...Konjac glucomannan (KGM) was crosslinked with sodium tripolyphosphate (STPP) to synthesize hydrogels. The crosslinking reaction was confirmed by FT-IR. The results of degradation test show that the hydrogels retain the enzymatic degradation character of KGM and can be degraded for 74.45% in 5 days by cellulase E0240.展开更多
The transformation of molecular conformation after gelatinization of konjac glucomannan ischaracterized by means of GC, GPC, FT-IR, DSC, XRD and TEM. The results showed that the molecule ofKGM had no branch, the monos...The transformation of molecular conformation after gelatinization of konjac glucomannan ischaracterized by means of GC, GPC, FT-IR, DSC, XRD and TEM. The results showed that the molecule ofKGM had no branch, the monose composition and connecting type of the molecular chain had no change,the transformation of molecule weight was little, and its drying powder sample formed an evidently newcrystalline region. The hollow double helix structure of KGM in hydrosol changed from stretch chain into in-tercross and entwisted after gelatinization. The gelatin formation mechanism of konjac glucomannan is there-by expounded.展开更多
Molecular dynamics (MD) method is adopted to simulate the conformation variations of konjac glucomannan (KGM) saline solution at different temperatures, and structurally analyze the trends and reasons of viscosity cha...Molecular dynamics (MD) method is adopted to simulate the conformation variations of konjac glucomannan (KGM) saline solution at different temperatures, and structurally analyze the trends and reasons of viscosity change in KGM saline solution with temperature. The experimental results have been analyzed to find out that the sum of formative hydrogen bonds decreases with the rise of temperature and the amount of intramolecular hydrogen bonds suddenly increases at 323 K. Besides, in terms of molecular orbital data obtained from simulation, we can know that hydrogen bonding energy also decreases with the rise of temperature. Therefore, we can predict the viscosity of KGM saline solution decreases gradually when rising the temperature.展开更多
In this paper, the hydrogen bonding network models of konjac gluco- mannan (KGM) are predicted in the approach of molecular dynamics (MD). These models have been proved by experiments whose results are consistent with...In this paper, the hydrogen bonding network models of konjac gluco- mannan (KGM) are predicted in the approach of molecular dynamics (MD). These models have been proved by experiments whose results are consistent with those from simulation. The results show that the hydrogen bonding network structures of KGM are stable and the key linking points of hydrogen bonding network are at the O(6) and O(2) positions on KGM ring. Moreover, acetyl has significant influence on hydrogen bonding network and hydrogen bonding network structures are more stable after deacetylation.展开更多
Biological activity of konjac glucomannan is closely related to its structure,in particular to its high-level structure.Researches on the activity mechanism of konjac glucomannan are significant for revealing the myst...Biological activity of konjac glucomannan is closely related to its structure,in particular to its high-level structure.Researches on the activity mechanism of konjac glucomannan are significant for revealing the mysteries of participation in life activity.In this paper,analysis of the effects of konjac glucomannan configuration and various factors on its structure and activity was conducted,mechanism of biological activity of konjac glucomannan was explored,and the hot research topic of konjac glucomannan was given.展开更多
Konjac glucomannan (KGM) with good water solubility was extracted and purified by a cheap and simple method including fat extraction, protein extraction, decolouring, centrifuge, precipitate and other procession from ...Konjac glucomannan (KGM) with good water solubility was extracted and purified by a cheap and simple method including fat extraction, protein extraction, decolouring, centrifuge, precipitate and other procession from tubers of amorphophallus riveiri. Acrylamide grafted konjac glucomannan (AKGM) was prepared in the presence of Ce(IV) serving as initiator in order to elucidate its molecular weight. Results from the measurements of capillary viscosity by figuring out the specific viscosity and applying to Mark Howink equation showed that the viscosity average molecular weight of acrylamide grafted konjac glucomannan was about 9.58×10 5.展开更多
An ultra-light and high porosity nano microfibril aerogel was prepared from konjac glucomannan(KGM) by the electrospinning and freeze-drying. The structure of aerogel was analyzed by scanning electron microscopy(SEM) ...An ultra-light and high porosity nano microfibril aerogel was prepared from konjac glucomannan(KGM) by the electrospinning and freeze-drying. The structure of aerogel was analyzed by scanning electron microscopy(SEM) and X-ray diffraction(XRD) while the density and compressive strength of the samples were studied separately. Results reveal that porous network structure of the KGM nano microfibril aerogel is constructed by intermolecular hydrogen bonds in random and interpenetrate way. The nano microfibril structure presents in the KGM aerogel,which is an important reason of its high density and compressive strength. There is a potential application for this unique nano microfibril aerogel in the absorption of biodegradation bacteria to solve problems in marine oil spill pollution.展开更多
Two kinds of new room temperature ionic liquids (RTILs), 1-allyl-3-methylimidazolium chloride (AMIMCl) and 1-butyl-3-methylimidazolium chloride (BMIMCl), were synthesized and used for the dissolution of konjac glucoma...Two kinds of new room temperature ionic liquids (RTILs), 1-allyl-3-methylimidazolium chloride (AMIMCl) and 1-butyl-3-methylimidazolium chloride (BMIMCl), were synthesized and used for the dissolution of konjac glucomannan (KGM). The experimental results showed that the solubility of KGM in AMIMCl was better than that in BMIMCl. Regenerated KGM were obtained by adding anhydrous alcohol to the KGM / ionic liquids solutions. Solubility, molecular weight, structure, and thermal property of the regenerated KGM were investigated by polarized optical microscopy (POM), viscosimetry, infrared spectroscopy (IR), X-ray diffraction technique (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). It was demonstrated that the viscosity-averaged molecular weight of the KGM samples decreased after regeneration because of the molecular degradation of KGM. Results from IR and XRD indicated that the chemical structure and the crystalline form of regenerated KGM were not changed. Results from TG and DSC showed that the thermal stability of the regenerated KGM samples only slightly decreased. These results suggest that AMIMCl and BMIMCl are direct and effective solvents for KGM.展开更多
In this work,the formation sites,helical parameters and hydrogen bond positions of Konjac glucomannan molecular helices were investigated using molecular dynamic simulation method.To our interest,the KGM chain is main...In this work,the formation sites,helical parameters and hydrogen bond positions of Konjac glucomannan molecular helices were investigated using molecular dynamic simulation method.To our interest,the KGM chain is mainly composed by local left and right helix structures. The formation sites of KGM chain might locate at the chain-segments containing acetyl groups,and the left helix is the favorable conformation of KGM.Temperature-dependent molecule conformation study indicates that the right helix is dominant when the temperature is lower than 343 K,above which,however,the left helix is dominating(right helix disappears).In addition,intramolecular hydrogen bonds in the left helix can be found at the-OH groups on C(2),C(4)and C(6)of mannose residues;comparably,the intramolecular hydrogen bonds in the right helix can be mainly observed at the-OH groups on C(4)and C(6)of the mannose residues and C(3)of the glucose residues.In conclusion,molecular dynamic simulation is an efficient method for the microscopic conformation study of glucomannan molecular helices.展开更多
The long-range structure of konjac glucomannan(KGM) is studied by using laser light scatter(LLS), gel permeation chromatography (GPC) and method of viscostdity. The weight-average molecularweight (Mw), root-mean-squar...The long-range structure of konjac glucomannan(KGM) is studied by using laser light scatter(LLS), gel permeation chromatography (GPC) and method of viscostdity. The weight-average molecularweight (Mw), root-mean-square ratio of gyration[ (S2) 1/2 ], second viral coefficient (A2) and multi-dispersioncoefficient (Mw/Mn) are 1.04× 106, 105.0±-0. 9 nm, (- 1.59±0. 28) × 10-3 mol ml g-2 and 1. 015±0. 003,respectively. Mark-Houwink equation is established as [η] = 5. 96 × 10-2Mw0.73 and the molecular chain pa-rameters are as follows: ML=982.82 nm-1 , Lp=27.93 nm, d=0.74 nm, h=0.26 nm, L=1 054.11 nm.Further more molecular chain morphology of KGM is studied by using atom force microscope (AFM) andtransmission electronic microscope (TEM), and the result shows that the KGM molecular is an extendingsemi-flexible linear chain without branch. Therefore, the image of molecular chain morphology confirms thededuction drawn by Mark-Houwink equation and molecular chain parameters.展开更多
To understand the effect of plasma treatment on the Konjac glucomannan film, the nitrogen plasma was injected into the film by ion beam injection machine in this study. The structures and properties of Konjac glucoman...To understand the effect of plasma treatment on the Konjac glucomannan film, the nitrogen plasma was injected into the film by ion beam injection machine in this study. The structures and properties of Konjac glucomannan film after plasma treatment were analyzed by Infrared spectroscopy, Raman spectrum, X-ray, ect. The result showed that nitrogen groups appeared in the KGM molecular chain and part of this chain fractured, and the number of hydrogen bonds increased after the treatment of plasma. The form of KGM molecule remained amorphous non-crystalline state, but the crystalline region was increased and became more ordered. The mechanical property of tensile strength and breaking elongation was improved, while the WVP was decreased. The nitrogen groups were grafted on the KGM molecular chain after plasma treatment, which led to the improvement of the properties of KGM film.展开更多
Based on the knot theory and researching of network structures of glucomannan molecules, the polysaccharides were analyzed. The link prediction analysis is to further reveal the interactions between polysaccharides, t...Based on the knot theory and researching of network structures of glucomannan molecules, the polysaccharides were analyzed. The link prediction analysis is to further reveal the interactions between polysaccharides, to elaborate QSAR of polysaccharides, and to analyze the network conformation relationships among polysaccharides. We made a classification for glucomannan molecules based on the related domestic and international theories, and investigated their network structures and application prospects. The knot theory and the link predictions not only simplify the glucomannan microscopic descriptions but also play a guiding role in predicting and regulating the structures.展开更多
In this paper,molecular dynamics simulation was applied to synthesize a layered structural color from Konjac glucomannan(KGM) and the effect of particle diameter and temperature were investigated. A series of methods ...In this paper,molecular dynamics simulation was applied to synthesize a layered structural color from Konjac glucomannan(KGM) and the effect of particle diameter and temperature were investigated. A series of methods such as high voltage electric field treatment,the transfer matrix method and the CIE standard colorimetric system were simulated to obtain the chromaticity coordinates and to analyze the color changes of KGM particles. The results revealed that as the particle diameter increases,the structural color of KGM particles deflects towards the yellow wavelength within the visible spectrum; and as the reaction temperature rises,the structural color deflects towards the blue and violet wavelengths within the visible spectrum.展开更多
Konjac glucomannan(KGM)was aminated by 2-chloroethyl-amine(CEA)as reagent so as to study the influence of concentration of CEA(based on the amount of KGM),concentration of NaOH,reaction time and temperature on the ext...Konjac glucomannan(KGM)was aminated by 2-chloroethyl-amine(CEA)as reagent so as to study the influence of concentration of CEA(based on the amount of KGM),concentration of NaOH,reaction time and temperature on the extent of amination.And the molecular simulation technology was adopted to analyze the conformation stability of aminate(AKGM).The results indicate that when the amount of CEA is higher,the extent of amination is higher.The optimum concentration of NaOH,reaction time and temperature are 10%NaOH,70℃and 45 min,respectively.IR shows KGM is successfully aminated.The conformation of AKGM is in a random clew-like shape.展开更多
With bamboo shoot shell nanofibers(BSN) and konjac glucomannan(KGM) as precursor materials, the BSN/KGM aerogels were prepared in different proportions by sol-gel method. The surface morphology, microstructure, charac...With bamboo shoot shell nanofibers(BSN) and konjac glucomannan(KGM) as precursor materials, the BSN/KGM aerogels were prepared in different proportions by sol-gel method. The surface morphology, microstructure, characteristic functional groups and thermal properties of BSN/KGM aerogels were characterized by scanning electron microscopy(SEM), infrared spectroscopy(IR), X-ray diffraction(XRD) and thermogravimetric analysis(TGA). The effect of BSN on the structure and properties of BSN/KGM aerogels was also studied. The results showed that the BSN/KGM aerogels possessed network porous structure with compact and homogeneous porosity, high specific surface area and low density. With the increase of BSN, the sheet structure of aerogels was converted into the 3D porous network structure, which contributes significantly higher thermal stability. In addition, the BSN/KGM aerogels showed excellent mechanical properties. The maximum relative compression rate was 62%, suggesting the addition of BSN can enhance the compression properties of the BSN/KGM aerogels.展开更多
文摘The gelating and swelling mechanisms of the hydrogel formed from oxidized konjac glucomannan (OKGM) and chitosan (CS) were studied by Fourier transform infrared (FT IR) spectrometry. FT IR spectra illustrate that the interaction of polysaccharides forms the hydrogen bonds and interchain salt bonds and the dissociation of which dominates the swelling behavior in buffer solutions of different pH. The concentration of salt ion has effect on swelling behavior through the difference of salt ion concentration between in solution and in network of hydrogel, which causes penetrating pressure. Moreover, the Swelling degree and hydrogel strength could be modulated by varying conditions. It is indicated that the hydrogel has pH sensitive and salt ion sensitive properties. The prepared optimum condition selected by varying conditions is that r = 0.2; t =30 min; T p =343 K and I =1.6.
基金the National Natural Science Foundation of China(32172240)BL19U2 beamline of National Facility for Protein Science in Shanghai(NFPS)at Shanghai Synchrotron Radiation Facility,for their assistance during data collection。
文摘Three materials(agar,konjac glucomannan(KGM)andκ-carrageenan)were used to prepare ternary systems,i.e.,sol-gels and their dried composites conditioned at varied relative humidity(RH)(33%,54%and 75%).Combined methods,e.g.,scanning electron microscopy,small-angle X-ray scattering,infrared spectroscopy(IR)and X-ray diffraction(XRD),were used to disclose howκ-carrageenan addition tailors the features of agar/KGM/κ-carrageenan ternary system.As affirmed by IR and XRD,the ternary systems withκ-carrageenan below 25%(agar/KGM/carrageenan,50:25:25,m/m)displayed proper component interactions,which increased the sol-gel transition temperature and the hardness of obtained gels.For instance,the ternary composites could show hardness about 3 to 4 times higher than that for binary counterpart.These gels were dehydrated to acquire ternary composites.Compared to agar/KGM composite,the ternary composites showed fewer crystallites and nanoscale orders,and newly-formed nanoscale structures from chain assembly.Such multi-scale structures,for composites withκ-carrageenan below 25%,showed weaker changes with RH,as revealed by especially morphologic and crystalline features.Consequently,the ternary composites with lessκ-carrageenan(below 25%)exhibited stabilized elongation at break and hydrophilicity at different RHs.This hints to us that agar/KGM/κ-carrageenan composite systems can display series applications with improved features,e.g.,increased sol-gel transition point.
基金financial support from the Natural Science Foundation of Shandong Province(ZR2015CM037)the National Science Foundation of China(31571890)。
文摘The stability against various environmental stresses of the curcumin-loaded secondary and tertiary emulsions that was emulsified by whey protein isolate(WPI)and coated by chitosan(CHI),carboxymethyl konjac glucomannan(CMKGM),or their combination through layer-by-layer assembly was investigated.Generally,the multilayered emulsions were destabilized in high Na Cl concentrations or medium p H that could interrupt the electrostatic interaction between the three polyelectrolytes or deprotonate CHI,indicating that electrostatic interaction played an important role in the stability of emulsions.Compared with the primary emulsion that was solely stabilized by WPI,extra coating with CHI and CMKGM generally increased the stability of the emulsion against repeated freezing-thawing,improved the retention of curcumin against heating,UV irradiation,and long-term storage,and the effects were more remarkable in the tertiary emulsion with CMKGM locating in the outmost layer.Since CMKGM has shown the colon-targeted delivery potency,the multilayered emulsions assembled by layer-by-layer deposition,especially the tertiary emulsion,could be used as an effective carrier for the targeted delivery of curcumin.
基金This work was supported by the National Natural Science Foundation of China (30371009), Science Foundation of Fujian Department of Education (JA03059) and Key Project of Science and Technology of Fujian Province (2003Y008)
文摘The simulation is carried out by employing the method of molecular dynamics with the single chain of konjac glucomannan (KGM) in vacuum as the structural model to discuss the factors that affect the single chain structure, the dynamic structure of the chain and the acting forces that maintain the chain structure. The results show that the shape and stability of the chain are affected by the degree of polymerization. As for the KGM with high degree of polymerization, its chain presents random coiling state and its stability declines. Both before and after deacetylation in the process of dynamic motion, the chain of KGM presents random coiling state with periodic variation of extension and coil and demonstrates favorable flexibility, indicating acetyl is not the main factor that affects the shape of chain, whereas dihedral angle and static actions are respectively the key bonding and nonbonding acting forces that influence the single chain conformations in vacuum.
基金Supported by the National Science Foundation of China( No.2 99770 14 )
文摘In order to improve the mechanical and water swelling properties of the chitosan(CS) film, a series of transparent films were prepared by blending 2%(weight) chitosan acetic acid solution with 1.5%(weight) carboxymethylated konjac glucomannan(CMKGM) aqueous solution according to predetermined ratio and drying at 30℃. The morphological structure, miscibility, thermal stability, mechanical properties, and swelling capacity of the blend films were studied by infrared (IR), X-ray diffraction(XRD), differential thermal analysis(DTA), scanning electron micrograph(SEM), and measurements of the mechanical properties and swelling properties. The results demonstrated that there was strong interaction and good miscibility between CS and CMKGM resulted from intermolecular hydrogen bonding and electrostatic force. The mechanical properties in dry state and wet state, thermostability, and water swelling properties of the blend films were obviously improved. The best values of the tensile strength in the dry and wet state achieved 89 MPa and 49 MPa,respectively, when the CMKGM content was 30%(weight). The CS/CMKGM blend films provided promising biomedical applications.
基金The authors are grateful for the financial support of the National Science Foundation of China(Grant No.20174029)National Key Basic Research and Development Program(G1999064703).
文摘Konjac glucomannan (KGM) was crosslinked with sodium tripolyphosphate (STPP) to synthesize hydrogels. The crosslinking reaction was confirmed by FT-IR. The results of degradation test show that the hydrogels retain the enzymatic degradation character of KGM and can be degraded for 74.45% in 5 days by cellulase E0240.
文摘The transformation of molecular conformation after gelatinization of konjac glucomannan ischaracterized by means of GC, GPC, FT-IR, DSC, XRD and TEM. The results showed that the molecule ofKGM had no branch, the monose composition and connecting type of the molecular chain had no change,the transformation of molecule weight was little, and its drying powder sample formed an evidently newcrystalline region. The hollow double helix structure of KGM in hydrosol changed from stretch chain into in-tercross and entwisted after gelatinization. The gelatin formation mechanism of konjac glucomannan is there-by expounded.
基金Supported by the National Natural Science Foundation of China (30371009)Science Foundation of Fujian Department of Education (JA03059)Key Project of Science and Technology of Fujian Province (2003Y008)
文摘Molecular dynamics (MD) method is adopted to simulate the conformation variations of konjac glucomannan (KGM) saline solution at different temperatures, and structurally analyze the trends and reasons of viscosity change in KGM saline solution with temperature. The experimental results have been analyzed to find out that the sum of formative hydrogen bonds decreases with the rise of temperature and the amount of intramolecular hydrogen bonds suddenly increases at 323 K. Besides, in terms of molecular orbital data obtained from simulation, we can know that hydrogen bonding energy also decreases with the rise of temperature. Therefore, we can predict the viscosity of KGM saline solution decreases gradually when rising the temperature.
基金supported by the National Natural Science Foundation of China(30371009, 30471218) Science Foundation of Fujian Department of Education (JA03059)
文摘In this paper, the hydrogen bonding network models of konjac gluco- mannan (KGM) are predicted in the approach of molecular dynamics (MD). These models have been proved by experiments whose results are consistent with those from simulation. The results show that the hydrogen bonding network structures of KGM are stable and the key linking points of hydrogen bonding network are at the O(6) and O(2) positions on KGM ring. Moreover, acetyl has significant influence on hydrogen bonding network and hydrogen bonding network structures are more stable after deacetylation.
基金Sponsored by the National Natural Science Foundation of China (No.30871749,30901004 and 31071518)Special Research Fund of Institution of Higher Learning of Ministry of Education for the Doctoral Program of Joint Funding(20113515110010)+3 种基金Natural Science Foundation of Fujian Province (No.2011J01285)a scientific problem-tackling project of Guangdong Province (No.2010B080701079)a Guangzhou Yangcheng Scholar Scientific Project (No.10B005D)Fuzhou Science and Technology Plan Project (2011-N-44)
文摘Biological activity of konjac glucomannan is closely related to its structure,in particular to its high-level structure.Researches on the activity mechanism of konjac glucomannan are significant for revealing the mysteries of participation in life activity.In this paper,analysis of the effects of konjac glucomannan configuration and various factors on its structure and activity was conducted,mechanism of biological activity of konjac glucomannan was explored,and the hot research topic of konjac glucomannan was given.
文摘Konjac glucomannan (KGM) with good water solubility was extracted and purified by a cheap and simple method including fat extraction, protein extraction, decolouring, centrifuge, precipitate and other procession from tubers of amorphophallus riveiri. Acrylamide grafted konjac glucomannan (AKGM) was prepared in the presence of Ce(IV) serving as initiator in order to elucidate its molecular weight. Results from the measurements of capillary viscosity by figuring out the specific viscosity and applying to Mark Howink equation showed that the viscosity average molecular weight of acrylamide grafted konjac glucomannan was about 9.58×10 5.
基金supported by the National Natural Science Foundation of China((31471704 and 31271837)major projects of industries,university and research in Fujian Province(2013N5003)
文摘An ultra-light and high porosity nano microfibril aerogel was prepared from konjac glucomannan(KGM) by the electrospinning and freeze-drying. The structure of aerogel was analyzed by scanning electron microscopy(SEM) and X-ray diffraction(XRD) while the density and compressive strength of the samples were studied separately. Results reveal that porous network structure of the KGM nano microfibril aerogel is constructed by intermolecular hydrogen bonds in random and interpenetrate way. The nano microfibril structure presents in the KGM aerogel,which is an important reason of its high density and compressive strength. There is a potential application for this unique nano microfibril aerogel in the absorption of biodegradation bacteria to solve problems in marine oil spill pollution.
基金Funded by the National Natural Scieace Foundation of China(50703031)
文摘Two kinds of new room temperature ionic liquids (RTILs), 1-allyl-3-methylimidazolium chloride (AMIMCl) and 1-butyl-3-methylimidazolium chloride (BMIMCl), were synthesized and used for the dissolution of konjac glucomannan (KGM). The experimental results showed that the solubility of KGM in AMIMCl was better than that in BMIMCl. Regenerated KGM were obtained by adding anhydrous alcohol to the KGM / ionic liquids solutions. Solubility, molecular weight, structure, and thermal property of the regenerated KGM were investigated by polarized optical microscopy (POM), viscosimetry, infrared spectroscopy (IR), X-ray diffraction technique (XRD), thermogravimetry (TG) and differential scanning calorimetry (DSC). It was demonstrated that the viscosity-averaged molecular weight of the KGM samples decreased after regeneration because of the molecular degradation of KGM. Results from IR and XRD indicated that the chemical structure and the crystalline form of regenerated KGM were not changed. Results from TG and DSC showed that the thermal stability of the regenerated KGM samples only slightly decreased. These results suggest that AMIMCl and BMIMCl are direct and effective solvents for KGM.
基金supported by the National Natural Science Foundation of China (30871749,30901004)Natural Science Foundation of Fujian Province(2009J01061)
文摘In this work,the formation sites,helical parameters and hydrogen bond positions of Konjac glucomannan molecular helices were investigated using molecular dynamic simulation method.To our interest,the KGM chain is mainly composed by local left and right helix structures. The formation sites of KGM chain might locate at the chain-segments containing acetyl groups,and the left helix is the favorable conformation of KGM.Temperature-dependent molecule conformation study indicates that the right helix is dominant when the temperature is lower than 343 K,above which,however,the left helix is dominating(right helix disappears).In addition,intramolecular hydrogen bonds in the left helix can be found at the-OH groups on C(2),C(4)and C(6)of mannose residues;comparably,the intramolecular hydrogen bonds in the right helix can be mainly observed at the-OH groups on C(4)and C(6)of the mannose residues and C(3)of the glucose residues.In conclusion,molecular dynamic simulation is an efficient method for the microscopic conformation study of glucomannan molecular helices.
文摘The long-range structure of konjac glucomannan(KGM) is studied by using laser light scatter(LLS), gel permeation chromatography (GPC) and method of viscostdity. The weight-average molecularweight (Mw), root-mean-square ratio of gyration[ (S2) 1/2 ], second viral coefficient (A2) and multi-dispersioncoefficient (Mw/Mn) are 1.04× 106, 105.0±-0. 9 nm, (- 1.59±0. 28) × 10-3 mol ml g-2 and 1. 015±0. 003,respectively. Mark-Houwink equation is established as [η] = 5. 96 × 10-2Mw0.73 and the molecular chain pa-rameters are as follows: ML=982.82 nm-1 , Lp=27.93 nm, d=0.74 nm, h=0.26 nm, L=1 054.11 nm.Further more molecular chain morphology of KGM is studied by using atom force microscope (AFM) andtransmission electronic microscope (TEM), and the result shows that the KGM molecular is an extendingsemi-flexible linear chain without branch. Therefore, the image of molecular chain morphology confirms thededuction drawn by Mark-Houwink equation and molecular chain parameters.
基金sponsored by the National Natural Science Foundation of China(No.30901004,31071518 and 31271837)the Fuzhou Science and Technology Plan(No.2011-N-44)+1 种基金the Guangdong Province Science and Technology Plan(No.2010B080701079)Guangzhou Yangcheng Scholar Scientific Project in Universities(No.10B005D)
文摘To understand the effect of plasma treatment on the Konjac glucomannan film, the nitrogen plasma was injected into the film by ion beam injection machine in this study. The structures and properties of Konjac glucomannan film after plasma treatment were analyzed by Infrared spectroscopy, Raman spectrum, X-ray, ect. The result showed that nitrogen groups appeared in the KGM molecular chain and part of this chain fractured, and the number of hydrogen bonds increased after the treatment of plasma. The form of KGM molecule remained amorphous non-crystalline state, but the crystalline region was increased and became more ordered. The mechanical property of tensile strength and breaking elongation was improved, while the WVP was decreased. The nitrogen groups were grafted on the KGM molecular chain after plasma treatment, which led to the improvement of the properties of KGM film.
基金Supported by the National Natural Science Foundation of China(31271837 and 31071518)Specialized Research Fund for the Doctoral Program of Higher Education jointly funded by Ministry of Education(20113515110010)+2 种基金Special Research Funds from Ministry of Science and Technology(2012GA7200022)Major projects of industries,universities and research in Fujian Province(2013N5003)Natural Science Foundation of Fujian Province(2011J0101)
文摘Based on the knot theory and researching of network structures of glucomannan molecules, the polysaccharides were analyzed. The link prediction analysis is to further reveal the interactions between polysaccharides, to elaborate QSAR of polysaccharides, and to analyze the network conformation relationships among polysaccharides. We made a classification for glucomannan molecules based on the related domestic and international theories, and investigated their network structures and application prospects. The knot theory and the link predictions not only simplify the glucomannan microscopic descriptions but also play a guiding role in predicting and regulating the structures.
基金supported by the National Natural Science Foundation of China(31271837 and 31471704)the major project of Fujian Industry-Academy-Research Cooperation(2013N5003)+1 种基金the Natural Science Foundation(2011J0101)of Fujian Province,the Science and Technology Program under Fujian Provincial Department of Education(JA13439 and JA13440)the Science and Technology Program under Fujian Provincial Department of Forestry(20135)
文摘In this paper,molecular dynamics simulation was applied to synthesize a layered structural color from Konjac glucomannan(KGM) and the effect of particle diameter and temperature were investigated. A series of methods such as high voltage electric field treatment,the transfer matrix method and the CIE standard colorimetric system were simulated to obtain the chromaticity coordinates and to analyze the color changes of KGM particles. The results revealed that as the particle diameter increases,the structural color of KGM particles deflects towards the yellow wavelength within the visible spectrum; and as the reaction temperature rises,the structural color deflects towards the blue and violet wavelengths within the visible spectrum.
基金Supported by Foundation of Minnan Normal University,the Funding(type A,No.JA11167)from the Fujian Education DepartmentNational Natural Science Foundation of China(31071518 and 31271837)+2 种基金Joint Specialized Research Fund for the Doctoral Program of Higher Education,MOE(20113515110010)Science and Technology Planning Project of technological department(2012GA7200022)Natural Science Foundation of Fujian Province(2011J01285)
文摘Konjac glucomannan(KGM)was aminated by 2-chloroethyl-amine(CEA)as reagent so as to study the influence of concentration of CEA(based on the amount of KGM),concentration of NaOH,reaction time and temperature on the extent of amination.And the molecular simulation technology was adopted to analyze the conformation stability of aminate(AKGM).The results indicate that when the amount of CEA is higher,the extent of amination is higher.The optimum concentration of NaOH,reaction time and temperature are 10%NaOH,70℃and 45 min,respectively.IR shows KGM is successfully aminated.The conformation of AKGM is in a random clew-like shape.
基金supported by the National Natural Science Foundation of China(No.31471704)the Scientific Research Foundation of Graduate School of Fujian Agriculture and Forestry University(No.324-1122yb034)
文摘With bamboo shoot shell nanofibers(BSN) and konjac glucomannan(KGM) as precursor materials, the BSN/KGM aerogels were prepared in different proportions by sol-gel method. The surface morphology, microstructure, characteristic functional groups and thermal properties of BSN/KGM aerogels were characterized by scanning electron microscopy(SEM), infrared spectroscopy(IR), X-ray diffraction(XRD) and thermogravimetric analysis(TGA). The effect of BSN on the structure and properties of BSN/KGM aerogels was also studied. The results showed that the BSN/KGM aerogels possessed network porous structure with compact and homogeneous porosity, high specific surface area and low density. With the increase of BSN, the sheet structure of aerogels was converted into the 3D porous network structure, which contributes significantly higher thermal stability. In addition, the BSN/KGM aerogels showed excellent mechanical properties. The maximum relative compression rate was 62%, suggesting the addition of BSN can enhance the compression properties of the BSN/KGM aerogels.
