Active air flushing in a sensor-controlled fresh produce container system to maintain the desired modified atmosphere

摘要

Modified atmosphere (MA) containers equipped with an on/off-controlled perforation that can respond to real-time gas concentrations can contribute to maintaining the quality of fresh produce. In this study, an active flushing system was devised to flush the air promptly responding to the real-time O-2 concentration, and its capability to maintain the target O-2 level was compared to that of an O-2 switched passive diffusion tube system. A model container with dimensions of 32 x 23 x 18 cm was filled with 350 g spinach and submitted to storage testing under different control regimes and temperatures. The gas concentration in the spinach container was programmed to stay either exactly at 11% or in the range of 11-13%. While the O-2 switched passive diffusion tube system could properly control the O-2 concentration in the container at the desired level or range when the container was at the low temperature of 10 degrees C, it could not do so at 20 degrees C, resulting in O-2 concentrations that were too low and CO2 concentrations that were too high. The active flushing system was effective and satisfactorily controlled the gas concentration in the container at the desired level or range at both 10 and 20 degrees C. Compared to the O-2 switched passive diffusion tube system, the active flushing system was more prompt in its response to deviating atmospheric conditions, which was more pronounced in the range control mode. The container with the controlled MA was better at preserving the quality of the produce compared to a perforated control package