两种大米淀粉及其磷酸酯淀粉理化特性的比较研究

Comparison of the physicochemical properties of two rice varieties starch and its modified starches

对比分析2种大米(籼米和粳米)的全粉、淀粉和取代度均为0.068的磷酸酯淀粉的理化特性。粳米的全粉、淀粉和磷酸酯淀粉的膨胀力分别为7.5,10.7,21.6 g/g,分别高于籼米的全粉、淀粉和磷酸酯淀粉的膨胀力(5.8,8.9,17.4 g/g)。2种大米淀粉经磷酸酯化后透光率增高,相应淀粉的透光率次之,全粉的透光率最低,籼米的全粉、淀粉和磷酸酯淀粉的透光率分别低于粳米的全粉、淀粉和磷酸酯淀粉的透光率。经快速黏度分析仪测定的糊化特性结果表明,淀粉或变性淀粉膨胀力高,其峰值黏度和崩解值也高,此外,蛋白质含量和直链淀粉含量也极大的影响了淀粉的糊化特性。使用动态流变仪测定的流变特性表明,在相同的温度下,籼米的全粉、淀粉和变性淀粉的储能模量(G′)分别比粳米的全粉、淀粉和变性淀粉的储能模量(G′)高,对于相同的大米品种,全粉的储能模量(G′)最高,变性淀粉的储能模量(G′)最低。

This test mainly dealt with the physicochemical properties of the flours, starches and modified starches （substitution degree DS =0. 068） of two rice varieties, indica rice and japonica rice. The swelling powers of flour, starch and phosphate starch of japonica rice were 7.5, 10.7, 21.6 g/g respectively, significantly higher than that of indica rice （5.8, 8.9, 17.4 g/g）. Modified starches showed high- er transmittance compared to starches, and the transmittance of star- ches were slightly higher than the flours. The pasting property in vestigated with rapid visco analyzer （RVA） indicated that the higher the swelling power, the higher the peak viscosity and breakdown value of paste, and the pasting property was also affected by protein and amylose ingredients. The results of rheological properties determined using rheological rheometer showed that at same temperature, the storage modulus G′ of flour, starch and modified starch of indica rice were higher than that of japonica rice respectively. For each variety, flour showed the highest G′ , and lowest G′ of modified starch.