小麦淀粉的退火改性及其性质表征

【目的】对小麦淀粉进行退火（annealing）处理能够使其发生物理改性，以处理后淀粉的糊化温度（起始温度To、峰温Tp、终止温度Tc）为依据优化退火条件，并研究其颗粒形态与退火的相关性。【方法】利用差示扫描量热法（differential scanning calorimetry，DSC）并结合DPS数据分析软件对小麦淀粉退火过程中的水分含量、退火时间、退火温度3个因子进行优化；采用扫描电子显微镜（SEM）和激光粒度分析仪（LPA）研究退火处理对小麦淀粉颗粒形貌和大小的影响。【结果】根据DSC测得的热力学参数分析得出小麦淀粉退火的最优条件为：80%水分含量的条件下，45℃退火3 d。退火处理会改变小麦淀粉颗粒的外貌而不破坏其形状，且对A-淀粉的影响较B-淀粉明显，淀粉颗粒粒径也因退火而增大。【结论】经退火处理的小麦淀粉的糊化温度显著高于原淀粉，且淀粉糊化温度范围变窄，同时小麦淀粉颗粒外貌和粒径的变化与退火温度呈正相关。

The Annealing Modification and Characterization of Wheat Starch

【Objective】Annealing can change the physical properties of wheat starch, and the annealing conditions were optimized according to gelatinisation temperatures (To, Tp, Tc) of annealed wheat starches. The correlation of morphological characteristics and annealing was also studied. 【Method】Differential scanning calorimetry (DSC) and DPS data analysis software were used to study the gelatinisation temperatures, and the effects of moisture content, annealing time and annealing temperature on the gelatinisation temperature of native and annealed wheat starch were also investigated. Besides, the influence on the morphology and size of the annealed wheat starch granules was discussed by using Scanning Electron Microscope (SEM) and Laser Particle Size Analyzer (LPA). 【Result】The results showed that the optimum condition of the wheat starch was annealed at 80% moisture content for 3 d at 45℃. Annealing changed the surface of wheat starch granules without destroying its shape, and more obvious influence on A-type granules than B-type granules. At the same time, annealing increased starch granule diameter.【Conclusion】Annealing leads to elevation of starch gelatinisation temperatures and sharpening of the gelatinisation range, and there is a significant positive correlation between the changes of wheat starch granules and annealing temperature.