Centro de Investigación en Alimentación y Desarrollo, A.C., CTAOV, A.P. 1735, 83304 Hermosillo, Sonora, Mexico.
Centro de Investigación y Estudios Avanzados del IPN, Unidad Mérida, Departamento de Recursos del Mar, A.P.73 Cordemex, 97310 Mérida, Yucatán, Mexico.
Int J Biol Macromol. 2014 Aug;69:176-84. doi: 10.1016/j.ijbiomac.2014.05.044. Epub 2014 May 27.
The effects of the addition of glycerol (GLY) on the physicochemical and morphological properties of poly(vinyl alcohol) (PVA)-agar films were reported. PVA-agar films were prepared by solution cast method, and the addition of GLY in PVA-agar films altered the optical properties, resulting in a decrease in opacity values and in the color difference (ΔE) of the films. Structural characterization using Fourier transformation infrared (FTIR) spectroscopy and X-ray diffraction (XRD) indicated that the presence of GLY altered the intensity of the bands (from 1200 to 800cm(-1)) and crystallinity. The characterization of the thermal properties indicated that an increase in the agar content produces a decrease in the melting temperature and augments the heat of fusion. Similar tendencies were observed in plasticized films, but at different magnification. The formulation that demonstrated the lowest mechanical properties contained 25wt.% agar, whereas the formulation that contained 75wt.% agar demonstrated a significant improvement. The water vapor transmission rate (WVTR) and surface morphology analysis demonstrated that the structure of PVA-agar films is reorganized upon GLY addition. The physicochemical properties of PVA-agar films using GLY as a plasticizer provide information for the application of this formulation as packaging material for specific food applications.
甘油（GLY）的添加对聚乙烯醇（PVA）-琼脂薄膜的物理化学和形态特性的影响。通过溶液浇铸法制备 PVA-琼脂薄膜，GLY 的添加改变了薄膜的光学性质，导致不透明度值和色差（ΔE）降低。傅里叶变换红外（FTIR）光谱和 X 射线衍射（XRD）结构表征表明，GLY 的存在改变了带的强度（从 1200 到 800cm（-1））和结晶度。热性能的表征表明，琼脂含量的增加会降低熔点并增加熔融热。在增塑薄膜中观察到类似的趋势，但在不同的放大倍数下。表现出最低机械性能的配方含有 25wt.%的琼脂，而含有 75wt.%琼脂的配方则显著提高。水蒸气透过率（WVTR）和表面形貌分析表明，GLY 加入后 PVA-琼脂薄膜的结构发生重组。GLY 作为增塑剂的 PVA-琼脂薄膜的物理化学性质为该配方作为特定食品应用的包装材料的应用提供了信息。
