湿热处理对糯小麦淀粉理化性质的影响

Effect of heat-moisture treatment on the physicochemical properties of waxy wheat starch

【目的】研究不同湿热处理条件,包括时间、温度和水分含量,对糯小麦淀粉性质的影响.【方法】以糯小麦淀粉糊的透明度、溶解度和膨胀度、冻融稳定性、颗粒形貌及颗粒结晶性质的变化考察湿热处理对糯小麦淀粉的影响.【结果和结论】与原淀粉相比,经湿热处理后,糯小麦淀粉糊的透光率,溶解度,冻融稳定性指标均有一定程度的降低,而膨胀度有一个先降低后增加的过程.湿热处理后糯小麦淀粉的颗粒形状和大小基本没有发生改变,但颗粒表面变得不均匀,中央部位变得模糊,出现了裂纹和压痕,偏光十字强度减弱.X射线衍射分析数据也证实了偏光显微镜得到的结果,淀粉的相对结晶度降低,但湿热处理未改变糯小麦淀粉的结晶结构类型,仍为A型.

【Objective】The effect of heat-moisture treatment（ HMT） including time,temperature and water content,on the physicochemical properties of waxy wheat starch was investigated. 【Method】The pasting properties such as clarity,solubility,swelling power,freeze-thaw stability,morphology,and X-ray crystallinity of the starch were evaluated. 【Result and conclusion】HMT reduced the transparency,solubility and freeze-thaw stability of waxy wheat starch. However,the swelling power of waxy wheat starch decreased and then increased. HMT did not obviously change the particle shape and size of starch granules,but the surface of starch granules became uneven,and the central of the granules became blurred;some crack and indentation appeared. HMT reduced the birefringence intensity of starch granules. The X-ray diffractometry result revealed that HMT promoted a reduction in the starch relative crystallinity,but the native and HMT starch maintained the A diffraction pattern.