不同物理方法处理对碎米中淀粉特性的影响

采用挤压、微波、超声波三种物理方法对水分含量18%的碎米淀粉进行处理，研究分析碎米淀粉经物理方法处理前后的理化性质和结构变化。结果表明，碎米淀粉经微波和超声处理后酶解力增加，糊化黏度下降，而溶解度、膨胀力、糊化温度和直链淀粉含量变化不显著；两种淀粉颗粒表面棱角减少，淀粉颗粒晶型基本没有发生变化，淀粉结晶区降低。挤压后的碎米淀粉变化较大，颗粒形状为片状，凝沉性强，1.0 h后体积仅为3 mL，糊化温度明显降低至55.0 ℃，直链淀粉含量增长为30.75%，溶解度强，为0.59%，酶解力达到45%，X-射线主要衍射峰的强度降低。

Effect of different physical treatment on properties of rice starch

Broken rice starches with water content of 18% were treated by microwave radiation, ultrasonic sound and extrusion. The physicochemical properties and structures changes of rice starches after physical treatments were investigated. The results showed that the hydrolysis ability of the starches increased and the viscosity of rice starch decreased after microwave and ultrasonic treatments. However, the solubility, swelling properties, gelatinization temperature and amylose content were essentially constant. The surface edges of the two starch granules reduced, and crystal structure of the starch granule changed little, and the starch crystal zone decreased. The rice starch showed significantly change after extrusion, the shape of rice starch granule was in slice, the coagulation characteristic was strong, and the volume was only 3 ml after 1.0 h. The gelatinization temperature lowered to 55.0 ℃, the amylase content increased to 30.75%, the solubility was 0.59% and the hydrolysis ability was as strong as 45%. The intensity of X-ray diffraction peak decreased.