Lan Xiaohong, Li Yongfu, Xie Shichao, Wang Zhengwu
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
AarhusKarlshamn, Shanghai 200137, China.
Food Chem. 2015 Dec 1;188:632-40. doi: 10.1016/j.foodchem.2015.05.025. Epub 2015 May 7.
Starches from five underutilized tubers (canna, potato, Chinese yam, water chestnut, and taro) were extracted to investigate quantitative structure-property relationships (QSPR) in each starch using a combination of X-ray diffraction (XRD) and small-angle X-ray scattering (SAXS). Structural parameters of the tuber starches were determined using the paracrystalline model. Swelling power (SP), water solubility index (WSI), amylose leaching (AML), and thermal properties were also measured. The XRD results indicated that starches from Chinese yam, water chestnut, and taro are C-type starches with relatively high crystallinity (29.23-35.02%). In contrast, canna and potato starches are B-type starches exhibiting lower crystallinity and higher amylose content. The paracrystalline model provided a better fit for the C-type starches than for the B-type starches because the former was highly compressible (indicated by a higher "β" value). B-type starches, on the other hand, tend to be more rigid along the lamellar repeat direction, requiring the layers to bend to accommodate internal stress. The QSPR analysis showed that three structural parameters, "Ø", "β", and "Δρu", correlate well with the SP and WSI, and thus can be used to predict certain physicochemical properties.
提取了五种未充分利用的块茎（美人蕉、马铃薯、山药、荸荠和芋头）中的淀粉，采用X射线衍射（XRD）和小角X射线散射（SAXS）相结合的方法研究了每种淀粉的定量结构-性质关系（QSPR）。使用准晶模型确定了块茎淀粉的结构参数。还测量了膨胀力（SP）、水溶性指数（WSI）、直链淀粉浸出率（AML）和热性质。XRD结果表明，山药、荸荠和芋头的淀粉是具有相对较高结晶度（29.23 - 35.02%）的C型淀粉。相比之下，美人蕉和马铃薯淀粉是B型淀粉，结晶度较低，直链淀粉含量较高。准晶模型对C型淀粉的拟合效果比对B型淀粉更好，因为前者具有较高的可压缩性（由较高的“β”值表示）。另一方面，B型淀粉在层状重复方向上往往更刚性，需要层弯曲以适应内部应力。QSPR分析表明，“Ø”、“β”和“Δρu”这三个结构参数与SP和WSI具有良好的相关性，因此可用于预测某些物理化学性质。
