d'Avignon D A, Hung C C, Pagel M T, Hart B, Bretthorst G L, Ackerman J J
Department of Chemistry, Washington University, St. Louis, Missouri 63130.
Adv Exp Med Biol. 1991;302:485-508. doi: 10.1007/978-1-4899-0664-9_26.
Proton and deuterium NMR relaxation methods were used to characterize water compartmentalization and hydration in work-free wheat flour doughs. Transverse (spin-spin) relaxation measurements define three motionally unique water compartments in the work-free dough preparations. The apparent occupancy fraction and relative mobility of each water domain are found to be functions of moisture content, temperature, and flour type. Additionally, the number of relaxation-resolved water compartments and their characteristic relaxation rate constants are found to depend critically on both moisture content and the interpulse-delay employed for the multi-pulse relaxation experiments. Under controlled experimental conditions, dynamics between the three water compartments can be observed to be consistent with the onset of flour hydration. The most notable observation during the initial period of hydration is a loss of "free" or "loosely bound" water to environments characterized by less mobility. Freezing studies show that hard wheat doughs have slightly less amorphous, non-freezable water than do soft wheat flour doughs prepared under similar conditions.
质子和氘核磁共振弛豫方法被用于表征无加工小麦粉面团中的水的区室化和水合作用。横向（自旋-自旋）弛豫测量确定了无加工面团制剂中三个运动状态独特的水区室。发现每个水域的表观占有率分数和相对迁移率是水分含量、温度和面粉类型的函数。此外，发现弛豫分辨的水区室数量及其特征弛豫速率常数严重依赖于水分含量和多脉冲弛豫实验所采用的脉冲间隔延迟。在受控实验条件下，可以观察到三个水区室之间的动力学与面粉水合作用的开始一致。水合作用初期最显著的观察结果是“自由”或“松散结合”的水流失到迁移率较低的环境中。冷冻研究表明，在类似条件下制备的硬小麦面团比软小麦粉面团具有稍少的无定形、不可冷冻水。
