21种宁夏大米淀粉分子结构及特性的比较分析

Comparative Analysis of Starch Molecular Structure and Properties of 21 Rice Varieties in Ningxia

为探索宁夏稻区不同品种大米淀粉分子在结构及特性上的差异,采用碱法提取大米淀粉后,通过X射线衍射仪(X-ray diffractometer,XRD)、快速黏度测定仪(rapid viscosity analyzer,RVA)和傅里叶红外光谱仪(fourier transform infrared spectrometer,FTIR)测定分析21种宁夏稻区不同品种大米淀粉分子的晶型结构、结晶度、分子有序性及糊化特性。结果表明:所有大米淀粉分子均为A型结构;不同品种大米淀粉分子结晶度和有序性存在差异,“宁梗28号”结晶度最高,为32.96%;“水稻3”在1748 cm-1和2852 cm-1处产生特征吸收峰;所有大米淀粉RVA曲线均呈现先上升后下降再上升的变化趋势,其中“宁梗41号”黏滞性较强,热稳定性和耐剪切性较差,“843”黏滞性较差,“天降优169”有较好的热稳定性和耐剪切性;“宁梗41号”“稻花香4号”“宁香”的回生值较高。研究结果可为宁夏稻区不同大米品种分类及精细加工提供理论依据。

In order to explore the differences in molecular structure and characteristics of rice starch from different varieties of rice in Ningxia,the starch was extracted using the alkaline method.The crystal structure,crystallinity,molecular order,and gelatinization properties of rice starch from 21 different varieties in Ningxia were detected and analyzed through X-ray diffractometer(XRD),rapid viscosity analyzer(RVA),and Fourier transform infrared spectrometer(FTIR).The results showed that all rice starch molecules had an A-type structure.Different varieties of rice exhibited variations in crystallinity and molecular order,with‘Ninggeng 28’having the highest crystallinity at 32.96%.‘Rice 3’displayed characteristic absorption peaks at 1748 cm-1 and 2852 cm-1 in the infrared spectrum.All RVA curves of rice starch exhibited the trend of increase initialy,followed by a decrease,and increase later.Among them,‘Ninggeng 41’had the higher viscosity but poor thermal stability and shear resistance,while‘843’had low viscosity and‘Tianjiangyou 169’showed good thermal stability and shear resistance.The varieties'Ninggeng 41','Daohuaxiang 4',and'Ningxiang'demonstrated elevated levels of retrogradation.The results could provide a theoretical basis for the classification and fine processing of different rice varieties in Ningxia.