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Fukui-shi, Japan

Einhorn-Stoll U.,TU Berlin | Hatakeyama H.,Fukui University of Technology | Hatakeyama T.,Lignocel Research
Food Hydrocolloids | Year: 2012

Water can be bound to food components and products as non-freezing, freezing-bound and free water. The interactions are crucial for any application as well as for food consumption and digestion. DSC was applied to examine the amounts of the different types of water bound to pectin, a biomacromolecule that is used as gelling and stabilising agent in many food products. One commercial high-methoxylated citrus pectin and three modified samples, prepared by acidic and alkaline demethoxylation as well as amidation, were tested. The water content of dry samples depended mainly on the molecular parameters, especially the content of hydrophilic groups at the galacturonic acid that was increased by demethoxylation and amidation, as well as on monovalent cations of the pectins. The water-pectin interactions of wetted materials were additionally influenced strongly by the availability of hydrophilic groups that depended on material properties such as amorphous or crystalline state, powder bulk and solid density and porosity as well as particle size, surface and porosity. Small amorphous porous particles, whose polar groups were rapidly available without prior softening and swelling, accelerated water uptake. Non-freezing and freezing-bound water, bound closely to the pectin molecules, depended on the number and type of polar groups. Free water, bound in micro- and macro-capillaries as well as voids within and between the pectin particles, was influenced by hydrophilic as well as hydrophobic groups of the samples. There was a strong impact of the pre-treatment during processing and modification. © 2011 Elsevier Ltd. Source

Hatakeyama T.,Lignocel Research | Tanaka M.,Tohoku University | Hatakeyama H.,Fukui University of Technology
Acta Biomaterialia | Year: 2010

The structural change of water restrained by poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) was investigated by differential scanning calorimetry (DSC), since the biocompatibility of PMPC and related biopolymers is affected by the structure of water on the polymer surface. The phase transition behaviour of PMPC-water systems with a water content (Wc = mass of water/mass of dry sample, gg1) in the range 0-2.0 was measured in the temperature range-150 to 50 °C. Glass transition, cold crystallization and melting were observed. Cold crystallization, which has been suggested as an index of biocompatibility, was detected for PMPC with a Wc in the range 0.5-0.9. The amounts of two types of bound water, non-freezing water and freezing bound water, were calculated from the melting enthalpy. The amount of non-freezing water of PMPC was ∼0.48. It was found that the phase transition behaviour and amount of bound water of PMPC were quite similar to those of water-soluble polysaccharide electrolytes. The results indicate that the bound water, not the free water, is restrained by PMPC. © 2010 Published by Elsevier Ltd. on behalf of Acta Materialia Inc. All rights reserved. Source

Iijima M.,Nagasaki University | Takahashi M.,Shinshu University | Hatakeyama T.,Lignocel Research | Hatakeyama H.,Lignocel Research | Hatakeyama H.,Fukui University of Technology
Journal of Thermal Analysis and Calorimetry | Year: 2013

A broad temperature range of the gel-sol transition of κ-carrageenan was precisely examined by differential scanning calorimetry (DSC), thermomechanical analysis (TMA) and the falling ball method (FBM). κ-Carrageenan the transition temperature of which ranged from 290 to 350 K was used as a representative sample of a thermo-reversible hydrogel. The starting of transition attributed to dissociation of the weak cross-linking zone of aggregated double helices was detected as a change of expansion coefficient by TMA and as an endothermic deviation by DSC. Peak temperature of endotherm by DSC agreed well with the temperature where expansion changed from positive to negative value and this temperature was attributed to gel-sol transition caused by dissociation of double helices' assembly. Transition temperature measured by FBM was observed at a temperature higher than those obtained by DSC and TMA, which was attributed to decomposition of double helices. © Akadémiai Kiadó, Budapest, Hungary 2013. Source

Hatakeyama T.,Lignocel Research | Tanaka M.,Yamagata University | Hatakeyama H.,Fukui University of Technology
Journal of Biomaterials Science, Polymer Edition | Year: 2010

This review focuses on the thermal properties of bound water restrained by various kinds of polysaccharides and several synthetic polymers. The characteristic features of freezing bound water which is closely related with biocompatibility of polymers are summarized based on results obtained by differential scanning calorimetry. Glass transition, cold crystallization and melting of water-polysaccharide systems were observed. Three kinds of water, non-freezing, freezing bound and free water, were quantified from the enthalpy of melting of water in the system. Freezing bound water restrained by polysaccharides is in a metastable state. The equilibrium melting temperature of freezing bound water is lower than 0°C and the temperature decreases with decreasing water content. Nucleation and growth rate of freezing bound water were calculated from isothermal crystallization and the values were compared with those of free water. © 2010 Koninklijke Brill NV, Leiden. Source

Hatakeyama H.,Fukui University of Technology | Hatakeyama T.,Lignocel Research
Advances in Polymer Science | Year: 2010

Polymeric features of lignin and its potential as a bio-resource are reviewed, focusing on its characteristic structure and properties. Lignin is a random copolymer consisting of phenylpropane units having characteristic side chains. Lignin slightly crosslinks and takes an amorphous structure in the solid state. The molecular motion is observed as glass transition by thermal, viscoelastic and spectroscopic measurements. The hydroxyl group of lignin plays a crucial role in interaction with water. By chemical and thermal decomposition, a wide range of chemicals can be obtained from lignin that can be used as starting materials for synthetic polymers, such as polyesters, polyethers, and polystyrene derivatives. At the same time, a variety of polymers can be derived from lignin by simple chemical modification. The hydroxyl group acts as a reaction site for the above chemical reaction. © Springer-Verlag Berlin Heidelberg 2009. Source

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