This study aimed to develop and characterize biodegradable packaging film from blends of two natural polysaccharides,i.e.,agar and glucomannan.The glucomannan used was derived from the specific tuber plant Amorphophal...This study aimed to develop and characterize biodegradable packaging film from blends of two natural polysaccharides,i.e.,agar and glucomannan.The glucomannan used was derived from the specific tuber plant Amorphophallus oncophyllus(locally known as“porang”),which grows abundantly in Indonesian forests and remains underutilized.Various ratios of agar and porang-glucomannan(PG)proportions were formulated to produce a food packaging film,which was subsequently tested for its mechanical,physical,chemical,and thermal properties.The results showed that the inclusion of PG to the film formulations notably enhanced the stretchability of agar films,achieving maximum a twofold increase,while concurrently reducing their water resistance such as increased water solubility and water swelling for up to 125%and 105%,respectively.The mechanical and thermal properties,as well as the water vapor permeability of the resulting film,were significantly affected by the polymer matrix structure formed by the varying proportions of the two biopolymers.The enhancement of these properties was associated with a more solid/compact film structure,as corroborated by cross-sectional images obtained through SEM analysis.The study’s findings suggest that utilizing agar and porang biomass has significant potential for further development as an environmentally friendly food packaging material.展开更多
This study investigated the effect of konjac glucomannan(KGM)on the flotation separation of calcite and scheelite.Micro-flotation tests showed that under the action of 50 mg/L KGM,the floatability of calcite notably d...This study investigated the effect of konjac glucomannan(KGM)on the flotation separation of calcite and scheelite.Micro-flotation tests showed that under the action of 50 mg/L KGM,the floatability of calcite notably decreased,while the impact on scheelite was negligible,resulting in a recovery difference of 82.53%.Fourier transform infrared(FTIR)spectroscopy and atomic force micro-scopy(AFM)analyses indicated the selective adsorption of KGM on the calcite surface.Test results of the zeta potential and UV-visible absorption spectroscopy revealed that KGM prevented the adsorption of sodium oleate on the calcite surface.X-ray photoelectron spec-troscopy(XPS)analysis further confirmed the chemical adsorption of KGM on the calcite surface and the formation of Ca(OH)_(2).The density functional theory(DFT)simulation results were consistent with the flotation tests,demonstrating the strong adsorption perform-ance of KGM on the calcite surface.This study offers a pathway for highly sustainable and cost-effective mineral processing by utilizing the unique properties of biopolymers such as KGM to separate valuable minerals from gangue minerals.展开更多
Konjac glucomannan（KGM） is a water-soluble polysaccharide obtained from the roots and tubers of konjac plants. Recently, a degraded product of KGM, depolymerized KGM（DKGM）, has attracted attention because of its l...Konjac glucomannan（KGM） is a water-soluble polysaccharide obtained from the roots and tubers of konjac plants. Recently, a degraded product of KGM, depolymerized KGM（DKGM）, has attracted attention because of its low viscosity, improved hydrophily, and favorable physiological functions. In this review, we describe the preparation of DKGM and its prebiotic effects. Other health benefits of DKGM, covering antioxidant and immune activity, are also discussed, as well as its safety. DKGM could be a candidate for use as a tool for the treatment of various diseases, including intestinal flora imbalance, and oxidative-and immune-related disorders.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 temperatu...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 rain, respectively. IR shows KGM is successfully aminated. The conformation of AKGM is in a random clew-like shape.展开更多
Konjac glucomannan(KGM) has been generally used in food,film-former and biomedical applications,especially in the edible packing films due to its excellent film-forming ability,good biocompatibility and biodegrade-abi...Konjac glucomannan(KGM) has been generally used in food,film-former and biomedical applications,especially in the edible packing films due to its excellent film-forming ability,good biocompatibility and biodegrade-ability.It has the common flaws of natural polymers,such as low mechanical properties and poor antimicrobial activity,which severely limit their applications.In this paper,novel biodegradable films(NBF) of KGM with palmitoylated KGM(PKGM) were prepared by using the solventcasting technique.The structure,thermal and mechanical properties of the NBF were investigated.The results suggested that a strong hydrogen bonding was formed in NBF,which resulted in good miscibility between KGM and PKGM.The tensile strength and elongation at break of the NBF were enhanced significantly with the increase of PKGM in a certain range.With the addition of 0.75%PKGM by weight,tensile strength and elongation at break of NBF were improved largely to 117.12 MPa and 14.39%.From this work,we hope to provide one of the promising ways to design new edible food films and coatings materials with good mechanical properties.展开更多
In this paper, the hydrogen bonding network models of konjac glucomannan （KGM） are predicted in the approach of molecular dynamics （MD）. These models have been proved by experiments whose results are consistent wi...In this paper, the hydrogen bonding network models of konjac glucomannan （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, acety has significant influence on hydrogen bonding network and hydrogen bonding network structures are more stable after deacetylation.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 retai...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 method of molecular dynamics simulation is carried out to simulate the KGM segment in solution, investigate the stable conformation and compute its energy, and discuss the effect of the change of hydrogen bond on ...The method of molecular dynamics simulation is carried out to simulate the KGM segment in solution, investigate the stable conformation and compute its energy, and discuss the effect of the change of hydrogen bond on its structure and energy. The results show that the structure of KGM segment can be optimized by molecular simulation method and the most stable conformation can be found, indicating the hydrogen bond is the main factor influencing the conformation and property of KGM.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 viscosidity. The weight-average molecular weight(Mw), root-mean-square r...The long-range structure of konjac glucomannan(KGM)is studied by using laser light scatter(LLS), gel permeation chromatography(GPC)and method of viscosidity. The weight-average molecular weight(Mw), root-mean-square ratio of gyration[(S2)1/2], second viral coefficient(A2)and multi-dispersion coefficient(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 parameters are as follows: ML=982. 82 nm-1, Lp = 27. 93 nm, d = 0. 74 nm, h = 0. 26 nm, L = l 054.11 nm. Further more molecular chain morphology of KGM is studied by using atom force microscope(AFM)and transmission electronic microscope(TEM), and the result shows that the KGM molecular is an extending semi-flexible linear chain without branch. Therefore, the image of molecular chain morphology confirms the deduction drawn by Mark-Houwink equation and molecular chain parameters.展开更多
The transformation of molecular conformation after gelatinization of konjac glucomannan is characterized by means of GC, GPC, FT-IR, DSC, XRD and TEM. The results showed that the molecule of KGM had no branch, the mon...The transformation of molecular conformation after gelatinization of konjac glucomannan is characterized by means of GC, GPC, FT-IR, DSC, XRD and TEM. The results showed that the molecule of KGM 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 new crystalline region. The hollow double helix structure of KGM in hydrosol changed from stretch chain into intercross and entwisted after gelatinization. The gelatin formation mechanism of konjac glucomannan is thereby expounded.展开更多
The formation mechanism and stability of konjac glucomannan （KGM） helical structure were investigated by molecular dynamic simulation and experimental method. The results indicate that the molecular conformation of ...The formation mechanism and stability of konjac glucomannan （KGM） helical structure were investigated by molecular dynamic simulation and experimental method. The results indicate that the molecular conformation of KGM is a non-typical helical structure. In detail, helical structure of KGM is mainly sustained by acetyl group, whose size and stability are affected by the molecular polymerization degree of KGM. In vacuum among the non-bonding interactions, electrostatic force is the greatest factor affecting its helical structure, but in water solution, hydrogen bond affects the helical arrangement greatly. To our interest, temperature exhibits a reversible destroying effect to some extent; the helical structure will disappear completely and present a ruleless clew-like arrangement till 341 K. This work suggests that the method of combining molecular dynamic simulation and experiment tools can be effective in the study of KGM helical structure.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...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
Konjac glucomannan nano gel microfibrils were prepared by using electrospinning method. Topology structures were analyzed by Fourier transform infrared spectroscopy （FT-IR） and Field emission scanning electron micro...Konjac glucomannan nano gel microfibrils were prepared by using electrospinning method. Topology structures were analyzed by Fourier transform infrared spectroscopy （FT-IR） and Field emission scanning electron microscopy （FESEM）, while the differential scanning calorimetry （DSC） was carried out to check the thermal stability of the structure. Results reveal that the interaction of KGM intermolecular hydrogen bonds and topological tangle rate are increased by electrospirming, while stable structures of nano gel microfibrils are formed without altering the molecular groups of origin, These structures compose of topological networks of clustered nano fibers with lower porosity and higher density.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 str...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
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
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 ...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 struetttres. 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
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
The effect of boron on the properties of Konjac Glucomanan （KGM） has been investigated by the method of experiment and molecular dynamic simulation. Upon analysis, the property and structure of KGM are apt to be aff...The effect of boron on the properties of Konjac Glucomanan （KGM） has been investigated by the method of experiment and molecular dynamic simulation. Upon analysis, the property and structure of KGM are apt to be affected by boron and structural reasons for property change were discussed. In detail, the addition low concentration borax can increase the systematic inherent viscosity, by contrast, high concentration borax has opposite effect on the viscosity. When adding borax, the micropores on KGM film surface decrease or disappear, leading to more compact and uniform on the film surface. The structure of KGM-Boron complex is described as the coordination reaction between KGM and boron. The main reaction points are hydroxyl group on C（6） position of sugar as well as those on C（2） and C（3） positions of mannose with two kinds of complexes formation： B-K2 and KB-K. And KB-K mainly consists of g-b-m.展开更多
A study was under taken to investigate the effect of dietary supplementations of humic acid and esterified glucomannan) on broiler performance and the morphological measurements of small intestine. Two hundred and ten...A study was under taken to investigate the effect of dietary supplementations of humic acid and esterified glucomannan) on broiler performance and the morphological measurements of small intestine. Two hundred and ten day old broiler chicks were weighed and randomly assigned to seven treatment groups in triplicate. The dietary treatments included T1) control (basal diet without any additives), T2) basal diets supplemented with 0.1% humic acid, T3) basal diets supplemented with 0.2% humic acid, T4) basal diets supplemented with 0.3% humic acid, T5) basal diets supplemented with 0.1% esterified glucomannan, T6) basal diets supplemented with 0.2% esterified glucomannan and T7) basal diets supplemented with 0.3% esterified glucomannan. Different parameters including body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR) and morphology of small intestine were evaluated during six weeks of experimental period. According to the results, at the end of experimental period, the highest average BWG were recorded in T4 group (fed with 0.3% humic acid), compared to control (T1) and other experimental groups (p < 0.05). Where as, the highest body weight gain were observed during starter period in treatment 7 (fed with 0.3% esterified glucomannan) as compare to other experimental groups (p < 0.05). Statistically, feed intake remained unaffected during the experimental period in all the treatment groups. However, the lowest and the highest feed intake were observed numerically within treatments T4 and T1 with 4229.70 g and 4362.30 g, respectively. Addition of dietary supplements used in the study appeared to have significant effect on the morphology of the small intestine (jejunum mucosal development) of the broilers in different treatment groups. Compared to control group, the inclusion of either humic acid or esterified glucomannon decreased (p < 0.01) the crypt depth and increased villus height respectively (p < 0.05). More ever, the diet supplements with humic acid 0.3% (T4) decreased crypt depth compared to esterified glucomannan and control. The dietary supplementations resulted in an increase in the villus height of intestinal mucosa of broilers. The increase in the villus height was associated with improvement of growth performance for both humic acid and esterified glucomannan. Based on our results it appeared that humic acid and esterified glucomannan can be used as a growth promoter in broiler diets and they can improve the gut health too.展开更多
The local maxima of water density in the space near the single-helical of Konjac glucomannan as well as the dominant conformation of the system was studied by molecular dyna-mics under the water environment. The resul...The local maxima of water density in the space near the single-helical of Konjac glucomannan as well as the dominant conformation of the system was studied by molecular dyna-mics under the water environment. The results indicate that the hydration shell,potential energy,and its hydrogen bond network with water bridges of the left-handed single-helix conformation was favored compared to those of right-handed single-helix conformation. This work suggests that the left-handed single-helix conformation was the dominant conformation of KGM in the water environment.展开更多
基金funded by a research grant from the Lembaga Pengelola Dana Pendidikan-Ministry of Finance Republic of Indonesia(https://risprolpdp.kemenkeu.go.id/)(accessed on 13 September 2024)awarded under the Riset dan Inovasi untuk Indonesia Maju program with grant number 82/II.7/HK/2022.
文摘This study aimed to develop and characterize biodegradable packaging film from blends of two natural polysaccharides,i.e.,agar and glucomannan.The glucomannan used was derived from the specific tuber plant Amorphophallus oncophyllus(locally known as“porang”),which grows abundantly in Indonesian forests and remains underutilized.Various ratios of agar and porang-glucomannan(PG)proportions were formulated to produce a food packaging film,which was subsequently tested for its mechanical,physical,chemical,and thermal properties.The results showed that the inclusion of PG to the film formulations notably enhanced the stretchability of agar films,achieving maximum a twofold increase,while concurrently reducing their water resistance such as increased water solubility and water swelling for up to 125%and 105%,respectively.The mechanical and thermal properties,as well as the water vapor permeability of the resulting film,were significantly affected by the polymer matrix structure formed by the varying proportions of the two biopolymers.The enhancement of these properties was associated with a more solid/compact film structure,as corroborated by cross-sectional images obtained through SEM analysis.The study’s findings suggest that utilizing agar and porang biomass has significant potential for further development as an environmentally friendly food packaging material.
基金supported by the National Natural Science Foundation of China(No.52164022).
文摘This study investigated the effect of konjac glucomannan(KGM)on the flotation separation of calcite and scheelite.Micro-flotation tests showed that under the action of 50 mg/L KGM,the floatability of calcite notably decreased,while the impact on scheelite was negligible,resulting in a recovery difference of 82.53%.Fourier transform infrared(FTIR)spectroscopy and atomic force micro-scopy(AFM)analyses indicated the selective adsorption of KGM on the calcite surface.Test results of the zeta potential and UV-visible absorption spectroscopy revealed that KGM prevented the adsorption of sodium oleate on the calcite surface.X-ray photoelectron spec-troscopy(XPS)analysis further confirmed the chemical adsorption of KGM on the calcite surface and the formation of Ca(OH)_(2).The density functional theory(DFT)simulation results were consistent with the flotation tests,demonstrating the strong adsorption perform-ance of KGM on the calcite surface.This study offers a pathway for highly sustainable and cost-effective mineral processing by utilizing the unique properties of biopolymers such as KGM to separate valuable minerals from gangue minerals.
基金Project supported by the National First-Class Discipline Program of Light Industry Technology and Engineering(Nos.LITE2018-18 and LITE2018-11) of Chinathe Transformation Project for Major Scientific and Technological Achievements in Jiangsu Province(No.BA2015006)+1 种基金the Industry-Academia Cooperation Innovation Fund Project of Jiangsu Province(No.BY2016022-19)the National Key Technologies R&D Program of China for the 12th Five-year Plan(No.2012BAD33B06)
文摘Konjac glucomannan（KGM） is a water-soluble polysaccharide obtained from the roots and tubers of konjac plants. Recently, a degraded product of KGM, depolymerized KGM（DKGM）, has attracted attention because of its low viscosity, improved hydrophily, and favorable physiological functions. In this review, we describe the preparation of DKGM and its prebiotic effects. Other health benefits of DKGM, covering antioxidant and immune activity, are also discussed, as well as its safety. DKGM could be a candidate for use as a tool for the treatment of various diseases, including intestinal flora imbalance, and oxidative-and immune-related disorders.
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 rain, respectively. IR shows KGM is successfully aminated. The conformation of AKGM is in a random clew-like shape.
文摘Konjac glucomannan(KGM) has been generally used in food,film-former and biomedical applications,especially in the edible packing films due to its excellent film-forming ability,good biocompatibility and biodegrade-ability.It has the common flaws of natural polymers,such as low mechanical properties and poor antimicrobial activity,which severely limit their applications.In this paper,novel biodegradable films(NBF) of KGM with palmitoylated KGM(PKGM) were prepared by using the solventcasting technique.The structure,thermal and mechanical properties of the NBF were investigated.The results suggested that a strong hydrogen bonding was formed in NBF,which resulted in good miscibility between KGM and PKGM.The tensile strength and elongation at break of the NBF were enhanced significantly with the increase of PKGM in a certain range.With the addition of 0.75%PKGM by weight,tensile strength and elongation at break of NBF were improved largely to 117.12 MPa and 14.39%.From this work,we hope to provide one of the promising ways to design new edible food films and coatings materials with good mechanical properties.
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 glucomannan （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, acety has significant influence on hydrogen bonding network and hydrogen bonding network structures are more stable after deacetylation.
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.
基金This work was supported by the National Natural Science Foundation of China (30371009), Foundation of Education Committee of Fujian Province (JA03059) and Key Science & Technology Item of Fujian Province (2003Y008)
文摘The method of molecular dynamics simulation is carried out to simulate the KGM segment in solution, investigate the stable conformation and compute its energy, and discuss the effect of the change of hydrogen bond on its structure and energy. The results show that the structure of KGM segment can be optimized by molecular simulation method and the most stable conformation can be found, indicating the hydrogen bond is the main factor influencing the conformation and property of KGM.
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 viscosidity. The weight-average molecular weight(Mw), root-mean-square ratio of gyration[(S2)1/2], second viral coefficient(A2)and multi-dispersion coefficient(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 parameters are as follows: ML=982. 82 nm-1, Lp = 27. 93 nm, d = 0. 74 nm, h = 0. 26 nm, L = l 054.11 nm. Further more molecular chain morphology of KGM is studied by using atom force microscope(AFM)and transmission electronic microscope(TEM), and the result shows that the KGM molecular is an extending semi-flexible linear chain without branch. Therefore, the image of molecular chain morphology confirms the deduction drawn by Mark-Houwink equation and molecular chain parameters.
文摘The transformation of molecular conformation after gelatinization of konjac glucomannan is characterized by means of GC, GPC, FT-IR, DSC, XRD and TEM. The results showed that the molecule of KGM 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 new crystalline region. The hollow double helix structure of KGM in hydrosol changed from stretch chain into intercross and entwisted after gelatinization. The gelatin formation mechanism of konjac glucomannan is thereby expounded.
基金supported by the National Natural Science Foundation of China (30871749, 30901004) the Natural Science Foundation of Fujian Province (2009J01061)
文摘The formation mechanism and stability of konjac glucomannan （KGM） helical structure were investigated by molecular dynamic simulation and experimental method. The results indicate that the molecular conformation of KGM is a non-typical helical structure. In detail, helical structure of KGM is mainly sustained by acetyl group, whose size and stability are affected by the molecular polymerization degree of KGM. In vacuum among the non-bonding interactions, electrostatic force is the greatest factor affecting its helical structure, but in water solution, hydrogen bond affects the helical arrangement greatly. To our interest, temperature exhibits a reversible destroying effect to some extent; the helical structure will disappear completely and present a ruleless clew-like arrangement till 341 K. This work suggests that the method of combining molecular dynamic simulation and experiment tools can be effective in the study of KGM helical structure.
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(31471704 and 31271837)major projects of industries,university and research in Fujian Province(2013N5003)
文摘Konjac glucomannan nano gel microfibrils were prepared by using electrospinning method. Topology structures were analyzed by Fourier transform infrared spectroscopy （FT-IR） and Field emission scanning electron microscopy （FESEM）, while the differential scanning calorimetry （DSC） was carried out to check the thermal stability of the structure. Results reveal that the interaction of KGM intermolecular hydrogen bonds and topological tangle rate are increased by electrospirming, while stable structures of nano gel microfibrils are formed without altering the molecular groups of origin, These structures compose of topological networks of clustered nano fibers with lower porosity and higher density.
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.
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 struetttres. 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.
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This work was supported by the National Natural Foundation (30371009), Foundation of Education Committee of Fujian Province(JA03059) and Key Science & Technology Item of Fujian Province (2003Y008).
文摘The effect of boron on the properties of Konjac Glucomanan （KGM） has been investigated by the method of experiment and molecular dynamic simulation. Upon analysis, the property and structure of KGM are apt to be affected by boron and structural reasons for property change were discussed. In detail, the addition low concentration borax can increase the systematic inherent viscosity, by contrast, high concentration borax has opposite effect on the viscosity. When adding borax, the micropores on KGM film surface decrease or disappear, leading to more compact and uniform on the film surface. The structure of KGM-Boron complex is described as the coordination reaction between KGM and boron. The main reaction points are hydroxyl group on C（6） position of sugar as well as those on C（2） and C（3） positions of mannose with two kinds of complexes formation： B-K2 and KB-K. And KB-K mainly consists of g-b-m.
文摘A study was under taken to investigate the effect of dietary supplementations of humic acid and esterified glucomannan) on broiler performance and the morphological measurements of small intestine. Two hundred and ten day old broiler chicks were weighed and randomly assigned to seven treatment groups in triplicate. The dietary treatments included T1) control (basal diet without any additives), T2) basal diets supplemented with 0.1% humic acid, T3) basal diets supplemented with 0.2% humic acid, T4) basal diets supplemented with 0.3% humic acid, T5) basal diets supplemented with 0.1% esterified glucomannan, T6) basal diets supplemented with 0.2% esterified glucomannan and T7) basal diets supplemented with 0.3% esterified glucomannan. Different parameters including body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR) and morphology of small intestine were evaluated during six weeks of experimental period. According to the results, at the end of experimental period, the highest average BWG were recorded in T4 group (fed with 0.3% humic acid), compared to control (T1) and other experimental groups (p < 0.05). Where as, the highest body weight gain were observed during starter period in treatment 7 (fed with 0.3% esterified glucomannan) as compare to other experimental groups (p < 0.05). Statistically, feed intake remained unaffected during the experimental period in all the treatment groups. However, the lowest and the highest feed intake were observed numerically within treatments T4 and T1 with 4229.70 g and 4362.30 g, respectively. Addition of dietary supplements used in the study appeared to have significant effect on the morphology of the small intestine (jejunum mucosal development) of the broilers in different treatment groups. Compared to control group, the inclusion of either humic acid or esterified glucomannon decreased (p < 0.01) the crypt depth and increased villus height respectively (p < 0.05). More ever, the diet supplements with humic acid 0.3% (T4) decreased crypt depth compared to esterified glucomannan and control. The dietary supplementations resulted in an increase in the villus height of intestinal mucosa of broilers. The increase in the villus height was associated with improvement of growth performance for both humic acid and esterified glucomannan. Based on our results it appeared that humic acid and esterified glucomannan can be used as a growth promoter in broiler diets and they can improve the gut health too.
基金supported by the National Natural Science Foundation of China (30871749,30901004,31071518)Natural Science Foundation of Fujian Province (2009J01061)
文摘The local maxima of water density in the space near the single-helical of Konjac glucomannan as well as the dominant conformation of the system was studied by molecular dyna-mics under the water environment. The results indicate that the hydration shell,potential energy,and its hydrogen bond network with water bridges of the left-handed single-helix conformation was favored compared to those of right-handed single-helix conformation. This work suggests that the left-handed single-helix conformation was the dominant conformation of KGM in the water environment.
