不同类型玉米灌浆期淀粉的热力学和晶体特性

Starch Thermal Property and Crystallization of Different Corn Types During Grain Grouting

以普通玉米、糯玉米、爆裂玉米和甜玉米为材料,采用差示扫描量热仪(DSC)和X-射线衍射仪分析玉米籽粒灌浆过程中淀粉热力学特性和晶体特性的变化趋势和差异。结果表明,随着籽粒灌浆,DSC糊化峰向低温方向移动,峰宽增大,峰值、糊化温度、热焓及结晶度呈逐渐降低趋势。说明与籽粒灌浆后期相比,灌浆前期的玉米淀粉较难糊化。类型间比较,糯玉米和甜玉米分别具有最大和最小的热焓。说明糯玉米淀粉难以糊化,甜玉米淀粉容易糊化。

Normal corn, waxy corn, pop corn and sweet corn have been utilized as materials to determine the alteration and differences of starch thermal properties and crystallization during grain grouting processing by differential scanning calorimetry （DSC） and X -ray diffraction. The results indicated that DSC peak value tended to occur at a low temperature and peak width broadened with grain grouting conduction. The peak value, gelatinization temperature （ To, Tp and Tc）, enthalpy of transition （△ Hgel ） and crystallinity degree expressed a decreased tendency during grain grouting processing. Corn starch at the early filling stage occurred gelatinization more difficultly than those in the late filling stage. Waxy corn and sweet corn had the biggest and smallest enthalpy of transition respectively. Waxy corn starch occurred gelatinization difficultly and sweet corn starch occurred gelatinization easily.