Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) studies of corn at subzero temperatures

The physical states of water and its freezing behaviour in shelled corn during subzero drying were determined by using 2H NMR and 1H MRI techniques. In this context, the 2H NMR spin-lattice relaxation times (T 1) and spin-spin relaxation times (T 2) of water in corn were measured. The relaxation times were found to decrease with decreasing temperature. The results revealed that there were two main water components in corn of >30% wb (wet basis) with long and short T 1. Both components exhibited minima around -20 °C. In more dehydrated corn (18.6% wb) only a single water component, with short T 1 and T 2 was observed. 1H MRI images revealed the location of water and its freezing behaviour in different areas.