Controlled thawing of foods

The various ways of thawing of model food made for comparison of these processes from point of view of duration. The experiments were conducted under condition that the surface temperature of the thawed food did not overcome 15°C. Shortest mean time of thawing was achieved for vacuum-steam thawing. Regarding to the regime chosen the time of thawing varied between 18.4-29 min. The similar process of vacuum thawing with steam generated from hot water placed below the food was also successful. For this process the mean time of thawing was predicted between 30.5 and 35 min. If the starting temperature of the water was below the boiling point at vacuum level in the chamber the time of thawing was much longer (about 49 min). For hot air thawing we have tested two regimes with temperature of air 50 and 70°C. For both air temperatures the times of thawing were similar being 52.1 and 53.6 min, respectively. Microwave thawing was depending on the power of microwave oven. The time of thawing was achieved 28.9 min at power level 1, at power level "thawing" the process duration was 34.4 min.