Gebhardt R, Hanfland M, Mezouar M, Riekel C
European Synchrotron Radiation Facility, Grenoble Cedex, France.
Biomacromolecules. 2007 Jul;8(7):2092-7. doi: 10.1021/bm070156s. Epub 2007 Jun 6.
Potato starch granules have been examined by synchrotron radiation small- and wide-angle scattering in a diamond anvil cell (DAC) up to 750 MPa. Use of a 1 microm synchrotron radiation beam allowed the mapping of individual granules at several pressure levels. The data collected at 183 MPa show an increase in the a axis and lamellar period from the edge to the center of the granule, probably due to a gradient in water content of the crystalline and amorphous lamellae. The average granules radius increases up to the onset of gelatinization at about 500 MPa, but the a axis and the lamellar periodicity remain constant or even show a decrease, suggesting an initial hydration of amorphous growth rings. The onset of gelatinization is accompanied by (i) an increase in the average a axis and lamellar periodicity, (ii) the appearance of an equatorial SAXS streak, and (iii) additional short-range order peaks.
利用金刚石对顶砧（DAC），在高达750兆帕的压力下，通过同步辐射小角和广角散射对马铃薯淀粉颗粒进行了研究。使用1微米的同步辐射束能够在几个压力水平下对单个颗粒进行成像。在183兆帕收集的数据显示，从颗粒边缘到中心，a轴和片层周期增加，这可能是由于结晶和无定形片层含水量的梯度所致。在约500兆帕的糊化起始点之前，平均颗粒半径增加，但a轴和片层周期性保持不变甚至减小，这表明无定形生长环开始水化。糊化起始伴随着：（i）平均a轴和片层周期性增加；（ii）赤道小角X射线散射条纹的出现；（iii）额外的短程有序峰。
