Xiao Qian, Gu Xiaohong, Tan Suo
School of Food Science and Technology, Hunan Agriculture University, Hunan 410128, China.
State Key Laboratory of Food Science and Technology, Jiangnan University, Jiangsu 214122, China.
Food Chem. 2014 Dec 1;164:179-84. doi: 10.1016/j.foodchem.2014.05.044. Epub 2014 May 20.
Drying process of aqueous sodium alginate solutions at 50°C was investigated by ATR-FTIR spectroscopy and two-dimensional correlation infrared spectroscopy. Two-dimensional asynchronous spectrum at 1,800-1,350 cm(-1) wavenumber could be resolved into five separate bands, which were assigned to O-H bending vibrations in water (around 1,645 cm(-1)), antisymmetric and symmetric stretching vibrations of free and hydrogen-bonded COO(-) groups of alginate (around 1,595, 1,412, 1,572 and 1,390 cm(-1), respectively). As the drying process progressed, absorbance bands at around 1,127 and 1,035 cm(-1) significantly shifted to lower wavenumbers (1120 and 1027cm(-1), respectively). Suggesting that oxygen atoms at the 2th and 3th position in the pyranose ring might have hydrogen bonded with water or alginate chains. Further analysis using 2D asynchronous correlation spectroscopy between 1800-1500 and 1200-960 cm(-1) wavenumber regions revealed the sequence of spectral changes during the drying process.
采用衰减全反射傅里叶变换红外光谱（ATR-FTIR）和二维相关红外光谱研究了50℃下海藻酸钠水溶液的干燥过程。在1800 - 1350 cm⁻¹波数处的二维异步光谱可解析为五个独立的谱带，分别归属于水中O-H弯曲振动（约1645 cm⁻¹）、海藻酸钠游离和氢键合的COO⁻基团的反对称和对称伸缩振动（分别约为1595、1412、1572和1390 cm⁻¹）。随着干燥过程的进行，约1127和1035 cm⁻¹处的吸收带显著向低波数移动（分别为1120和1027 cm⁻¹）。这表明吡喃糖环中第2和第3位的氧原子可能与水或海藻酸链形成了氢键。在1800 - 1500和1200 - 960 cm⁻¹波数区域之间使用二维异步相关光谱进行的进一步分析揭示了干燥过程中光谱变化的顺序。
