• Title/Summary/Keyword: spin-spin relaxation time constant $(T_{2})$

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Effect of Modified Starches on Caking Inhibition in Ramen Soup

  • Wee, Hye-Won;Choi, Young-Jin;Chung, Myong-Soo
    • Food Science and Biotechnology
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    • v.16 no.4
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    • pp.646-649
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    • 2007
  • The effect of the addition of 2 kinds of chemically modified starches (the anti-caking agents; tapioca starch and com starch) on caking of ramen soup was observed using a low-resolution proton-pulsed nuclear magnetic resonance (NMR) technique. After storing ramen soup samples with diverse compositions of modified starch at 20-40% relative humidity for 4 weeks, changes in the spin-spin relaxation time constant ($T_2$) were measured as a function of temperature. $T_2-Temperature$ curves for ramen soup containing modified starches showed that the caking initiation temperature (glass transition temperature) was increased by $5^{\circ}C$ following the addition of only 0.5% modified cornstarch. The results indicate that the modified com starch used in this study would be an effective anti-caking agent for ramen soup, thus prolonging the shelf life of the product.

Structural Characteristics of 3- and 4-Coordinate Borons from 11B MAS NMR and Single-Crystal NMR in the Nonlinear Optical Material BiB3O6

  • Kim, Woo Young;Lim, Ae Ran
    • Journal of the Korean Magnetic Resonance Society
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    • v.17 no.1
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    • pp.24-29
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    • 2013
  • The structural characteristics of 4-coordinate $BO_4$ [B(1)] and 3-coordinate $BO_3$ [B(2)] groups in $BiB_3O_6$ were studied by $^{11}B$ magic angle spinning (MAS) and single-crystal nuclear magnetic resonance (NMR) spectroscopy. The spin-lattice relaxation time in the laboratory frame, $T_1$, for $^{11}B$ decreased slowly with increasing temperature, whereas the spin-lattice relaxation times in the rotating frame, $T_{1{\rho}}$, for B(1) and B(2), which differed from $T_1$, were nearly constant. Further, $T_{1{\rho}}$ for B(1) and B(2) showed very similar trends, although the $T_{1{\rho}}$ value of B(2) was shorter than that of B(1). The 3-coordinate $BO_3$ and 4-coordinate $BO_4$ were distinguished by $^{11}B$ MAS NMR spectrum and $T_{1{\rho}}$.

Observation of Molecular Relaxation Behavior of Glucose Powders with Different Structures and Particle Sizes Using Low Field Nuclear Magnetic Resonance (NMR) (NMR을 이용한 구조 및 입도 차이에 따른 분말 포도당의 molecular relaxation behavior의 관찰)

  • Chung, Myung-Soo
    • Korean Journal of Food Science and Technology
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    • v.34 no.6
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    • pp.1140-1144
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    • 2002
  • Molecular relaxation behaviors of crystalline glucose anhydrous, crystalline glucose monohydrate, and amorphous glucose with different particle sizes were observed by measuring spin-spin relaxation time constant $(T_2)$ at the temperature range of $-20\;to\;110^{\circ}C$ using temperature-controlled low field nuclear magnetic resonance spectroscopy. No change in $T_2$ values of crystalline glucose anhydrous was observed throughout the temperature range, whereas $T_2$ values of crystalline glucose monohydrate and amorphous glucose increased from around $45\;and\;65^{\circ}C$, respectively. These results indicate that molecular mobility of crystalline glucose anhydrous does not change even at temperature higher than $100^{\circ}C$ and that the stability of powdered glucose could be improved by increasing the particle size of materials.

Structural nature of chemically inequivalent borons in the nonlinear optical material β-BaB2O4 studied using 11B MAS NMR and 11B single-crystal NMR

  • Kim, Woo Young;Lim, Ae Ran
    • Journal of the Korean Magnetic Resonance Society
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    • v.17 no.2
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    • pp.86-91
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    • 2013
  • Detailed information about the structural nature of three-coordinate borons in ${\beta}-BaB_2O_4$ is obtained through $^{11}B$ MAS NMR and $^{11}B$ single-crystal NMR. The three-coordinate $BO_3$ of the two borons B(1) and B(2) in ${\beta}-BaB_2O_4$ were distinguished. The spin-lattice relaxation time in the laboratory frame $T_1$ for B(1) and B(2) slowly decreases with increasing temperature, whereas the spin-lattice relaxation time in the rotating frame $T_{1{\rho}}$ for B(1) and B(2), which differs from $T_1$, is nearly constant. The B(1) and B(2) of the two types were distinguished by $^{11}B$ MAS NMR and $^{11}B$ single-crystal NMR.