糯玉米灌浆结实期籽粒淀粉理化特性变化

 【目的】探明糯玉米籽粒淀粉理化特性在灌浆结实期的变化趋势。【方法】以糯玉米新品种NQ01和NQ11为材料，研究其灌浆结实期（花后10、20、30和40 d）籽粒淀粉理化特性的变化。【结果】随着灌浆进程推进，籽粒干重和淀粉含量逐渐升高，籽粒含水率、蛋白质和可溶性糖含量逐渐降低，籽粒鲜重和体积先升后降。淀粉粒随灌浆进程逐渐增大，且以花后10—20 d增加最为明显。结晶类型和碘结合力均表现出典型的糯性特征。差示扫描量热法（DSC）和快速黏度分析仪（RVA）研究表明，随着灌浆进程，转变温度和糊化温度降低，热焓值在花后20—40 d无显著差异，但显著高于花后10 d，回生值和黏度特征值两品种表现不一。【结论】碘结合力、晶体类型和回复值均表现出典型的糯性特征。糯玉米灌浆结实期理化特性有显著差异，淀粉粒大小和品质成分的变化引起了淀粉糊化和热力学特性发生变化，但品种间变化趋势存在差异。

Dynamics of Physicochemical Characteristics in Two Waxy Maize Varieties During Grain Filling

【Objective】 The objective of the experiment is to study the dynamics of physicochemical characteristics for waxy maize flour during grain filling. 【Method】 The grain weight, grain volume, water content, starch content, protein content, starch granule size, crystalline type, iodine binding capacity, thermal and pasting characteristics at 10, 20, 30, and 40 days after pollination (DAP) during grain filling were studied using two waxy maize varieties (NQ01 and NQ11) as materials. 【Result】 With the proceeding of grain filling, grain dry weight and starch content gradually increased, water content, protein content and soluble sugar content gradually decreased, while grain fresh weight and volume increased first and fell later. Starch granule size rapidly enlarged from 10 to 20 DAP, while crystalline type and iodine binding capacity presented typical waxy character during grain filling. The results from differential scanning calorimetry (DSC) and rapid viscosity analyzer (RVA) showed that the pasting temperature and transition temperature (onset, peak and conclusion temperature) were gradually decreased, enthalpy of gelatinization was similar from 20 to 40 DAP and lowest at 10 DAP, while the changing tendency of viscosity characteristics and the percentage of retrogradation were different for the 2 varieties. 【Conclusion】Iodine binding capacity, crystalline type and setback presented typical waxy character. The physicochemical characteristics were different during grain filling and the changing of starch granule size and flour quality components content induced the changing of pasting and thermal characteristics, and the dynamics were different between the two varieties.