College of Engineering, National Energy R & D Center for Non-food Biomass, China Agricultural University, PO Box 50, 17 Qinghua Donglu, Beijing 100083, China.
College of Food Science and Nutritional Engineering, Beijing Key Laboratory of Functional Food from Plant Resources, China Agricultural University, Beijing, China.
Carbohydr Polym. 2014 Nov 4;112:350-8. doi: 10.1016/j.carbpol.2014.05.080. Epub 2014 Jun 6.
The creep recovery, stress relaxation, temperature-dependence and their frequency-dependence of maize kernel were determined within a moisture content range of 11.9% to 25.9% (w/w) by using a dynamic mechanical analyzer. The 4-element Burgers model was found to adequately represent the creep behavior of the maize seeds (R(2)>0.97). The 5-element Maxwell model was able to better predict the stress relaxation behavior of maize kernel than the 3-element Maxwell model. The Tg values for the maize kernels decreased with increased moisture content. For example, the Tg values were 114 °C and 65 °C at moisture content values of 11.9% (w/w) and 25.9% (w/w), respectively. The magnitude of the loss moduli and loss tangent and their rate of change with frequency were highest at 20.7% and lowest at 11.9% moisture contents. The maize kernel structure exhibited A-type crystalline pattern and the microstructure was found to expand with increase in moisture content.
采用动态力学分析仪，在 11.9%至 25.9%（w/w）的水分范围内，测定了玉米籽粒的蠕变恢复、应力松弛、温度依赖性及其频率依赖性。发现四元件伯格模型能很好地描述玉米种子的蠕变行为（R(2)>0.97）。五元件麦克斯韦尔模型比三元件麦克斯韦尔模型更能准确预测玉米籽粒的应力松弛行为。玉米籽粒的 Tg 值随水分含量的增加而降低。例如，在水分含量为 11.9%（w/w）和 25.9%（w/w）时，Tg 值分别为 114°C 和 65°C。损耗模量和损耗正切的幅度及其随频率的变化率在 20.7%水分含量时最高，在 11.9%水分含量时最低。玉米籽粒结构呈现 A 型结晶形态，且微观结构随水分含量的增加而膨胀。
