Department of Food Science and Technology, Faculty of Nutrition Sciences and Food Technology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Int J Biol Macromol. 2011 Nov 1;49(4):471-9. doi: 10.1016/j.ijbiomac.2011.05.030. Epub 2011 Jun 2.
In this study, Iranian gum tragacanth (GT) exudates from Astragalus fluccosus (AFG) and Astragalus gossypinus (AGG) were irradiated at 3, 7, 10 and 15 kGy. Fourier transform infrared spectroscopy (FTIR) data showed that irradiation did not induce changes in the chemical structure of either type of gum. Although particle size distribution and both steady shear and dynamic rheological properties were considerably affected by the irradiation process, the magnitude of the effect of irradiation on each of the rheological and size variables was different for the hydrocolloids. For instance, for AGG, increasing the irradiation dose from 3 to 10 kGy, the d(0.5) and D[3,2] values were reduced by one-sixth to one-eighth fold. Colour measurement revealed that the radiation process led to an increase in the yellow index and b* values for both types of GT in powder form, but it was more pronounced for AGG samples. Irradiation led to an approximate 13-fold increase in redness in AFG. Surface and shape changes of the gum crystals were studied by scanning electron microscope (SEM) and a smoother surface for irradiated samples was detected. The notable changes in functional properties of each variety of irradiated gum should be taken into consideration before using the radiation technology as a commercial tool for sterilisation.
在这项研究中，来自 Astragalus fluccosus（AFG）和 Astragalus gossypinus（AGG）的伊朗橡胶树胶（GT）渗出物分别在 3、7、10 和 15 kGy 下进行了辐照。傅里叶变换红外光谱（FTIR）数据表明，辐照并未引起任何一种胶化学结构的变化。尽管粒度分布以及稳态剪切和动态流变性能都受到辐照过程的显著影响，但辐照对每种流变学和尺寸变量的影响程度因水胶体而异。例如，对于 AGG，将辐照剂量从 3 增加到 10 kGy，d(0.5)和 D[3,2]值降低了六分之一到八分之一。颜色测量表明，辐射过程导致两种类型的 GT 粉末的黄度指数和 b*值增加，但 AGG 样品更为明显。辐照导致 AFG 的红色值增加了约 13 倍。通过扫描电子显微镜（SEM）研究了胶晶的表面和形状变化，发现辐照样品的表面更光滑。在将辐射技术用作商业灭菌工具之前，应该考虑每种辐照胶的功能特性的显著变化。
