Konjac Mannan

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 246 Experts worldwide ranked by ideXlab platform

Katsuyoshi Nishinari - One of the best experts on this subject based on the ideXlab platform.

  • Natural eating behavior of two types of hydrocolloid gels as measured by electromyography: Quantitative analysis of mouthful size effects
    Food Hydrocolloids, 2016
    Co-Authors: Kaoru Kohyama, Fumiyo Hayakawa, Zhihong Gao, Sayaka Ishihara, Takahiro Funami, Katsuyoshi Nishinari
    Abstract:

    Abstract The objectives of this study are to identify mechanical properties that dictate natural oral processing of soft solid foods and to quantify the effects of mouthful sizes. Two types of hydrocolloid gels with similar fracture loads but different elastic moduli and fracture strains were prepared using agar (A) or a mixture of Konjac Mannan, κ-carrageenan, and locust bean gum (K). Subsequently, 3, 6, 12, and 24 g mouthfuls of A and K gels were randomly served to subjects and the effects of mechanical properties and mouthful sizes were quantitatively analyzed within an individual. Electromyographic (EMG) activities of both masseter muscles and the suprahyoid muscle were recorded as jaw-closing and jaw-opening muscles, respectively. Total 33 EMG variables relating mastication and swallowing difficulties were classified into six groups by influences of gel types and mouthful sizes. Despite similar fracture loads, K gels with greater fracture strain and work required more mastication effort and less swallowing effort than A gels, which had higher elastic modulus. Doubling of mouthful sizes between 3 g and 24 g increased oral processing times and the numbers of chewing actions and swallows by 1.4 fold. These variables were approximately proportional to 0.7 of the power of the mouthful mass, and they can be predicted using this relation. Mastication effort exhibited lower dependence on sample mass than the three variables and durations and muscle activities per masseter muscle action did not vary significantly with mouthful sizes and gel types.

  • A molecular description of the gelation mechanism of Konjac Mannan
    Biomacromolecules, 2000
    Co-Authors: Martin A. K. Williams, Timothy J. Foster, Dave R. Martin, Ian T. Norton, Miki Yoshimura, Katsuyoshi Nishinari
    Abstract:

    A molecular level description of the time course of the gelation of the polysaccharide Konjac Mannan (KM) is presented and the role of alkali addition is considered in detail. NMR relaxometry is utilized as a complementary methodology to mechanical spectroscopy in order to probe events occurring as a prelude to network formation, and high-resolution NMR is used to follow the deactetylation process. It is shown that the addition of alkali plays an important solubilizing role in addition to facilitating the deacetylation of the chain. Deacetylation is important both in reducing the inherent aqueous solubility of the polymer and in progressively negating the alkali-induced polyelectrolytic nature of the polysaccharide chain via reaction induced pH changes. It is proposed that observed induction periods following alkali addition (during which the elastic modulus does not rise) are not simply deacetylation delays but are related to the aggregation kinetics of the deacetylated material.

  • Interaction in Xanthan-GlucoMannan Mixtures and the Influence of Electrolyte
    Macromolecules, 1994
    Co-Authors: P. Annable, P. A. Williams, Katsuyoshi Nishinari
    Abstract:

    The interaction of xanthan and glucoMannan (Konjac Mannan, KM) has been monitored using DSC, ESR, and mechanical spectroscopy. The DSC and ESR results indicate that interaction occurs in water immediately following xanthan side chain-backbone association. The process is thermodynamically driven and occurs to reduce xanthan-water contacts. In the presence of electrolyte, both techniques show that the xanthan conformational change shifts to higher temperatures and depends on the nature of the cation. Divalent cations give rise to a greater shift than monovalent cations. The results indicate that xanthan/KM interaction occurs at temperatures much lower than the conformational transition

  • investigation of the gelation mechanism in kappa carrageenan Konjac Mannan mixtures using differential scanning calorimetry and electron spin resonance spectroscopy
    Macromolecules, 1993
    Co-Authors: Peter A Williams, M. J. Langdon, Katsuyoshi Nishinari, S. M. Clegg, L. Piculell
    Abstract:

    DSC and ESR spectroscopy have indicated that an association occurs between Konjac Mannan chains and (aggregated) κ-carrageenan helices. On cooling mixed systems at low ionic strength, a coil-helix transition of κ-carrageenan, as evidenced by a DSC exothermic peak (peak I), occurs at a temperature significantly higher than the «normal» transition temperature observed for κ-carrageenan alone. This transition is accompanied by a partial immobilization of the Konjac Mannan chains, as evidenced by ESR spectroscopy

  • Investigation of the gelation mechanism in .kappa.-carrageenan/Konjac Mannan mixtures using differential scanning calorimetry and electron spin resonance spectroscopy
    Macromolecules, 1993
    Co-Authors: Peter A Williams, M. J. Langdon, Katsuyoshi Nishinari, S. M. Clegg, L. Piculell
    Abstract:

    DSC and ESR spectroscopy have indicated that an association occurs between Konjac Mannan chains and (aggregated) κ-carrageenan helices. On cooling mixed systems at low ionic strength, a coil-helix transition of κ-carrageenan, as evidenced by a DSC exothermic peak (peak I), occurs at a temperature significantly higher than the «normal» transition temperature observed for κ-carrageenan alone. This transition is accompanied by a partial immobilization of the Konjac Mannan chains, as evidenced by ESR spectroscopy

Glyn O Phillips - One of the best experts on this subject based on the ideXlab platform.

  • Effects of γ-irradiation on molar mass and properties of Konjac Mannan
    Food Hydrocolloids, 2007
    Co-Authors: Panida Prawitwong, Shoji Takigami, Glyn O Phillips
    Abstract:

    Abstract Konjac Mannan (KM) is a water-soluble glucoMannan with high molar mass. Here, the effects of γ -irradiation on the structure of KM, its viscosity, molar mass distribution and the state of sorbed water were studied after irradiation at reduced pressure. These changes were investigated using ESR, FT-IR, UV, viscometer, SEC–MALS and DSC. Free radical yields increased with absorbed dose. Irradiation led to chain scission, but introduced no significant new chemical groups into the structure, apart from a small increase in content of carbonyl groups. The intrinsic viscosity, molar mass and radius of gyration decreased rapidly with increasing dose up to 10 kGy and then at a slower rate. The Mark–Houwink–Sakurada equation for the KM gave [ η ]=5.30×10 −4  M 0.78 . The α value showed that KM molecules are solvated in the form of random coils in water. There are three types of sorbed water in irradiated KM as in the original KM. There is no significant change in water binding ability for KM with M W greater than 2×10 5 .

  • Phase transition behaviour of sorbed water in Konjac Mannan
    Food Hydrocolloids, 2007
    Co-Authors: Panida Prawitwong, Shoji Takigami, Glyn O Phillips
    Abstract:

    Abstract Phase transition behaviour of sorbed water in Konjac Mannan (KM)-water system with various water contents ( W c ) was investigated using differential scanning calorimetry (DSC). The measurements were performed repeatedly for 3 cycles. At least six types of sorbed water together with glassy water can be identified in the KM-water system: (1) non-freezing water ( W nf ), (2) four types of freezing bound water ( W fb ), designated W fb1 , W fb2 , W fb2* and W fb3 and (3) free water ( W f ). Glassy water was closely related to W nf and the amount of glassy water was influenced by the cooling rate. The cold crystallization ( T cc ) of glassy water caused an under estimation of the weight of sorbed water when calculated for the first cycle. Thereafter, the effect of T cc was eliminated by cyclic measurements and the transition of W fb2* could be readily observed. The proportion of each type of sorbed water changed with increasing W c . The equivalent value of W nf per pyranose ring was ca. 5.2 (mol/mol). W fb1 , W fb2 and W fb2* were the W fb that were influenced by interaction with the KM matrix at lower W c regions and were transferred to W f in the high W c regions. W fb3 was strongly bound water, maintaining interaction with KM chains even in the high W c region; the equivalent value of W fb3 per pyranose ring was ca. 1.4 (mol/mol). Most of the sorbed water in the system with high W c was held as W f .

  • Microscopical studies of the tissue structure of Konjac tubers
    Food Hydrocolloids, 1997
    Co-Authors: Shoji Takigami, Tsuyoshi Takiguchi, Glyn O Phillips
    Abstract:

    Abstract The tissue structures of 2-year-old Konjac tubers were investigated using a variable pressure scanning electron microscope equipped with an energy-dispersive X-ray spectrometer and an optical microscope. Konjac Mannan (KM) cells are distributed all over the tuber and the spaces between the KM cells are filled with parenchyma. The KM cells are covered with scale-like cell walls and the size of the cells varies from 160 to 650 μ m. Other kinds of particles with different sizes are observed in the honeycombed cells around the KM cells. The small grains relate to protein granules and the spherical particles (~12 μ m in diameter), which are composed of small granules (1–3 μ m in diameter), are starch. The tuber also contains potassium and calcium in the parenchyma. Most calcium is found in the needle-like crystals in the form of calcium oxalate. Such crystals are also found in 1 year and seed tubers.

  • Synergistic interaction of xanthan gum with glucoMannans and galactoMannans
    Food Hydrocolloids, 1991
    Co-Authors: Peter A Williams, Glyn O Phillips, D.h. Day, M. J. Langdon, Katsuyoshi Nishinari
    Abstract:

    Abstract Xanthan gum forms thermoreversible gels when mixed with Konjac Mannan or locust bean gum. The stronger gels are formed with Konjac Mannan and the maximum gel strength for the mixed systems in the absence of electrolyte occurs at a xanthan-Konjac Mannan or xanthan-locust bean gum mixing ratio of about 1:1. In the presence of 0.04 mol/dm 3 NaCl the optimum mixing ratio is unchanged for xanthan-locust bean gum blends but changes to about 2:1 for xanthan-Konjac Mannan blends. These observations support differential scanning calorimetric data which are able to monitor both gelation and the conformational transition of the xanthan molecules and indicates that (i) in the absence of electrolyte Konjac Mannan interacts with disordered xanthan chains whilst in the presence of 0.04 mol/dm 3 NaCl it interacts with ordered xanthan chains, and (ii) locust bean gum interacts with ordered xanthan chains both in the presence and absence of electrolyte.

Peter A Williams - One of the best experts on this subject based on the ideXlab platform.

Victor J Morris - One of the best experts on this subject based on the ideXlab platform.

  • Synergistic interactions between the genetically modified bacterial polysaccharide P2 and carob or Konjac Mannan.
    Carbohydrate Research, 2004
    Co-Authors: Michael J. Ridout, P. Cairns, G.j. Brownsey, Victor J Morris
    Abstract:

    Rheological studies have confirmed that the bacterial polysaccharide P2, a genetically modified variant of the Acetobacter xylinum polysaccharide acetan, undergoes synergistic gelation with either of the plant polysaccharides carob or Konjac Mannan. X-ray fibre diffraction data shows that P2 can form a 5-fold helical structure of pitch 4.7nm and an axial rise per disaccharide repeat of 0.92nm. Optical rotation data demonstrate that P2 undergoes a coil-helix transition in solution and that deacylation enhances the stability of the helical structure in solution. Studies made on mixtures prepared at different temperatures and ionic strengths suggest that denaturation of the P2 helix favours interaction and gelation. Deacetylation of P2 enhances gelation. X-ray diffraction data for oriented fibres prepared from deacetylated P2-Konjac Mannan mixed films reveal a 6-fold helical structure of pitch 5.54nm with an axial rise per disaccharide repeat also of 0.92nm. This mixed helix provides direct evidence for binding between the two polysaccharides. P2 contains two sites of acetylation: one on the backbone and one on the sidechain. The former site of acetylation inhibits helix formation for P2. It is suggested that this site of acetylation also inhibits formation of the mixed helix, explaining the enhanced gelation of mixtures on deacetylation.

  • Acetan:glucoMannan interactions--a molecular modeling study.
    Carbohydrate research, 2003
    Co-Authors: Rengaswami Chandrasekaran, Srinivas Janaswamy, Victor J Morris
    Abstract:

    X-ray fiber diffraction patterns from deacylated acetan and glucoMannan (Konjac Mannan) blends are diagnostic of good orientation and modest polycrystallinity. The meridional reflection on the sixth layer line suggests that the binary complex is a 6-fold helix of pitch 55.4 A. A molecular modeling study incorporating this information reveals that a double helix in which one strand is acetan and the other glucoMannan is stereochemically feasible. While the backbone and side groups are sufficiently flexible to allow the chains to associate with the same or opposite polarity, the parallel model is superior in terms of unit cell packing. The results are compatible with the observed synergy; namely the weak gelation behavior of the complex. The molecular model can be generalized for the binary system when acetan is replaced by xanthan or glucoMannan by galactoMannan.

  • Synergistic Interactions of Acetan with Carob or Konjac Mannan
    Macromolecules, 1998
    Co-Authors: Michael J. Ridout, G.j. Brownsey, Victor J Morris
    Abstract:

    New experimental evidence has been obtained which demonstrates synergistic interaction of mixtures of acetan with carob or Konjac Mannan. These binary mixtures have been shown to form thermoreversible gels under conditions for which the individual components do not gel. The rheological properties of acetan−carob and acetan−Konjac Mannan mixtures have been studied at various concentrations above and below the threshold concentration for gelation. In dilute solutions, the synergisms manifested themselves as an enhancement of the viscosity, whereas at higher concentrations gelation occurred. The synergistic effects were much weaker for acetan−Konjac Mannan mixtures than for acetan−carob mixtures. Deacetylation of acetan enhanced the synergistic interactions, particularly for acetan−Konjac Mannan mixtures, and also altered the polymer ratio at which the maximum interactions were observed. The influence of the stability of the acetan helix on the gelation of the binary mixtures was investigated by varying the ...

  • Evidence for intermolecular binding between deacetylated acetan and the glucoMannan Konjac Mannan
    Carbohydrate research, 1998
    Co-Authors: Michael J. Ridout, P. Cairns, G.j. Brownsey, Victor J Morris
    Abstract:

    Abstract Binary mixtures of deacetylated acetan and Konjac Mannan form thermoreversible gels under conditions for which the individual components do not gel. Such synergistic behaviour is normally attributed to intermolecular binding between the two polysaccharides. X-ray diffraction data obtained from oriented fibres prepared from deacetylated acetan-Konjac Mannan gels provides direct evidence for intermolecular binding between the two polysaccharides. The novel heterotypic junction zones appear to be six-fold helices with a pitch of 5.6±0.1 nm.

  • Effect of deacetylation on the synergistic interaction of acetan with locust bean gum or Konjac Mannan
    Carbohydrate research, 1997
    Co-Authors: Cordelia Ojinnaka, G.j. Brownsey, Edwin R. Morris, Victor J Morris
    Abstract:

    Abstract It has been discovered that deacetylation of the bacterial polysaccharide acetan promotes synergistic interactions with either locust bean gum (LBG) or Konjac Mannan (KM). Acetan is similar in structure to xanthan, and adopts a similar 5-fold conformation in the solid state. Like xanthan, it shows a thermally reversible order (helix)-disorder (coil) transition in solution. Both polymers have a cellulosic backbone with charged (anionic) sidechains attached at O-3 of alternate glucosyl residues, but the sidechains in acetan are longer (pentasaccharide rather than trisaccharide) and do not contain pyruvic substituents. Acetan has two sites of acetylation, one at O-6 of the inner mannosyl residue of the carbohydrate sidechains (as in xanthan) and the other on the polymer backbone (believed to be at O-6 of the branched glucosyl residues). Solutions of acetan or deacetylated acetan were equilibrated against 10 mM potassium chloride (to stabilise the ordered conformation) and were mixed (at 25 °C) with solutions of LBG or KM, also equilibrated against 10 mM potassium chloride. Unlike xanthan, native acetan showed no evidence of synergistic interaction with either LBG or KM. After deacetylation, however, large enhancements were observed in dilute-solution viscosity, and thermoreversible gels were formed at higher concentrations. With KM as co-synergist, gel melting was accompanied by an intense endotherm in differential scanning calorimetry. The magnitude of this endotherm increased with storage time at 25 °C, reaching a final value of ΔH ≈ 15.9 J/g (in comparison with ΔH ≈ 5.0 J/g for the order-disorder transition of deacetylated acetan alone). It is suggested that interaction occurs by formation of heterotypic junctions between the acetan backbone and unsubstituted regions of the plant polysaccharide, and that the acetate groups on native acetan promote solubility and hence inhibit association.

L. Piculell - One of the best experts on this subject based on the ideXlab platform.

Related terms

Konjac Mannan - 15 days free trial to Access Experts & Abstracts