Low resolution pulse nuclear magnetic resonance study of water equilibration in dried carrots

Samples taken during air drying of carrots were analysed after different equilibration times. Low resolution NMR measurements were made and the longitudinal ( T ₁) and the transverse ( T ₂) relaxation times calculated. Both T ₁ and T ₂ decreased with the equilibration time for water contents above 0.30 and 0.47 kg water kg^-1 dry matter, respectively. The decrease in relaxation time increased with the water content. For the same water contents, grated carrots gave lower T ₁ values and smaller T ₁ decreases with equilibration time than 3-mm cubes. Low resolution NMR is a technique which is well suited to the monitoring of the tempering phases of industrial drying cycles.