Color and density of apple cubes dried in air and modified atmosphere

The color, density and porosity of apple cubes dried in air and modified atmospheres were measured to identify the potential of modified atmosphere drying for foods. The modified atmospheres were achieved by flushing nitrogen gas through a specially designed laboratory dryer. The drying temperature was varied from 17 to 75°C. The results indicated that dried apple cubes with no browning could be produced under low oxygen atmospheres. Thus, chemical additives, such as sulfur dioxide can be completely eliminated from the process. The temperature and oxygen levels in the drying atmosphere were important factors in achieving the best quality in terms of color. Apple cubes dried in low oxygen atmospheres gave more porous products than those dried in air. Moreover, apple cubes dried in a nitrogen atmosphere had the greater number of open pore structures connected to the the exterior surface of the cubes.