Studies of Physical State of Water in Maize from Northeast China (cv. Huangmo 417) During Drying at Subzero Temperatures

In northeastern provinces of China, maize is one of the main sources of income in agriculture. After harvest, the grain is kept under subzero conditions for 3-4 months. Studies have been undertaken to assess the feasibility of drying at subzero temperatures during storage. Using a combination of NMR and MRI enabled a better understanding of physical states of water in the cv. Huangmo 417 during drying at subzero temperatures. The studies showed two water components with different relaxation times (long and short T₁) that were found when temperature was lowered from +25 to -30°C. T₁ was a minimum when the temperature was reduced to -20°C. T₂ was found to be much shorter than T₁. This was an indication that water mobility was decreasing at the same time as the temperature. The results from MRI revealed the location of frozen water in different areas of the maize kernel during subzero drying. This approach to characterizing the states of water in maize under subzero conditions will assist in devising drying strategies for northeastern China.