Liu Wenchao, Wei Xinyu, Zhang Nan, Li Jiaxin, Li Lili, Li Linlin, Cao Weiwei, Duan Xu, Ren Guangyue
College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, China.
Agricultural Products Drying Equipment Engineering and Technology Research Centre of Henan Province, Luoyang, China.
J Food Sci. 2025 Jun;90(6):e70324. doi: 10.1111/1750-3841.70324.
This study systematically investigated the impact mechanism of hot-air drying temperature (40°C-80°C) on moisture migration, crack formation, and the microstructural evolution of corn kernels. Using multi-scale characterization techniques such as low-field nuclear magnetic resonance, scanning electron microscopy, and Fourier transform infrared spectroscopy, this study revealed temperature-gradient-driven changes in microscopic mechanical properties. The results showed that increasing the drying temperature accelerated moisture evaporation while exacerbating internal moisture gradients, which led to greater thermal stress and promoted crack formation. Under medium drying conditions (60°C-70°C), the efficiency of moisture migration was optimized, preventing structural hardening and uneven drying caused by high temperatures, thereby significantly reducing crack formation. Further microstructural and correlation analyses indicated that with increasing temperature, cornstarch granules underwent significant morphological changes, while the secondary structure of proteins transitioned from an ordered α-helix to a disordered random coil structure, thereby increasing the risk of crack formation. This study assessed a qualitative relationship between drying temperature, protein conformational changes, and crack formation, thus providing a molecular-level theoretical basis for optimizing the hot-air drying process of corn and offering significant practical value in reducing processing loss rates.
本研究系统地探究了热风干燥温度（40°C - 80°C）对玉米粒水分迁移、裂纹形成及微观结构演变的影响机制。通过低场核磁共振、扫描电子显微镜和傅里叶变换红外光谱等多尺度表征技术，本研究揭示了温度梯度驱动的微观力学性能变化。结果表明，提高干燥温度会加速水分蒸发，同时加剧内部水分梯度，从而导致更大的热应力并促进裂纹形成。在中等干燥条件（60°C - 70°C）下，水分迁移效率得到优化，可防止高温导致的结构硬化和干燥不均，从而显著减少裂纹形成。进一步的微观结构和相关性分析表明，随着温度升高，玉米淀粉颗粒发生显著的形态变化，而蛋白质的二级结构从有序的α - 螺旋转变为无序的无规卷曲结构，从而增加了裂纹形成的风险。本研究评估了干燥温度、蛋白质构象变化与裂纹形成之间的定性关系，从而为优化玉米热风干燥工艺提供了分子水平的理论依据，并在降低加工损失率方面具有重要的实际价值。
