The proton spin-spin relaxation behavior during 1H-NMR before and after heat treatment at 70°C for 30min was compared among typical groups of commercial foodstuffs which were classified according to the official standard tables of food composition in Japan.
Signal amplitudes all with delay times for most foodstuffs, except for vegetables, were significantly higher after heat treatment than those of the unheated group, due to the decrease in the proton population for the fast component and increase in the slow component. On the other hand, each proton population for vegetables after heat treatment was unchanged. The relaxation time of the slow component for vegetables mostly decreased due to the heat treatment while this component increased for the fish and shellfish.
Therefore, the proton behaviors during 1H-NMR may basically be characterized based on the cooking properties such as thermal stability in each foodstuff group classified according to the official tables.
