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Volume 23 (2015)
- Issue 2 Pages 63-
- Issue 1 Pages 1-
Volume 23, Issue 2
Displaying 1-3 of 3 articles from this issue
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Masanori Okazaki, Naoya Katsumi, Koyo Yonebayashi, Tomoe Nishi, Yuji H ...2015 Volume 23 Issue 2 Pages 63-68
Published: 2015
Released on J-STAGE: July 06, 2023
JOURNAL FREE ACCESSTo study the behavior of water molecules in the sago (Metroxylon sagu) starch (CA type starch) structure, a 1H solid state cross polarization (CP) magic angle spinning (MAS) nuclear magnetic resonance (NMR) technique has been applied using corn (type A starch) and potato (type B starch) as references. The exchange of H2O molecules on/in the sago starch structure to D2O based on the H-D isotopic exchange was analyzed with time from 1 to 24 hrs. The amount of water-molecule exchange on/in sago starch increased with the increasing contact time with D2O, which was similar to the exchange amount of water-molecule of corn starch and smaller than that of potato starch. This suggested that the type B starch holds a larger channel space of a hexagonal crystalline structure for water molecules than does the type A starch and that the type CA starch showed the dynamics of water molecules, similarly to type A.View full abstractDownload PDF (2750K) -
Masanori Okazaki, Shun Nishiyama, Naoya Katsumi, Fumi Kawashima, Koyo ...2015 Volume 23 Issue 2 Pages 69-76
Published: 2015
Released on J-STAGE: July 06, 2023
JOURNAL FREE ACCESSX-ray diffraction, one of the useful tools for the structural analysis of starch, was used for analysis of the reflection surface of a crystalline structure, resulting in determining the distance of the interlayered structure. The X-ray diffraction peak at about 5 to 6° for 2Θ Cu Kα of water-added starch with type B and type C crystallinity shifted to the smaller degree side than that of the original starch, suggesting the expansion of the interlayered distance by the invasion of water molecules. The invasion of water molecules into the structure expanded the lattice spacing of the cavity from 1.56 nm to 1.61 nm, which corresponded to about 1/6 of the diameter of a water molecule.View full abstractDownload PDF (311K) -
Shun Nishiyama, Masanori Okazaki, Naoya Katsumi, Yuji Honda, Mayuko Ts ...2015 Volume 23 Issue 2 Pages 77-83
Published: 2015
Released on J-STAGE: July 06, 2023
JOURNAL FREE ACCESSKnowing the characteristics of sago starch is necessary for the development of sago utilization. The mean diameter and nanostructure are characteristics of sago starch important for flocculation and dispersion, useful in printing, manufacturing paper and corrugated cardboard, and other industries. Sago starch granules are oval and bell shaped, with 37.59 μm of mean diameter in water and 37.73 to 38.27 μm in 0.01, 0.1, and 1 mol L-1 NaClO4 solution, which showed a C-type (mainly A-type (monoclinic) with B-type (hexagonal) as an accessory) X-ray diffraction pattern. Sago starch showed variable charge, and the surface charge of sago starch granules ranged from positive to negative with a point of zero charge at pH 6.1 in 0.1 mol L-1 NaClO4 solution. These results indicate that sago starch had the intermediate dynamics of a point of zero charge as compared to corn (pH 4.7) and potato starches (pH 6.0).View full abstractDownload PDF (1184K)
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