Cold Atmospheric-Pressure Plasmas Applied to Active Packaging of Apples

Active packaging of fruits and vegetables uses films that absorb molecules from or contribute molecules to the produce. The pilot application developed in this paper has resulted in the deposition of film to apples. A prospective application relates to replacing hot wax that is expensive and that lowers the textural quality of the apple. This was the early motivation of this paper. Moreover, the focus of this paper will be mostly on the reactor design and film evaluation. The cold-plasma zone was obtained by increasing the voltage on a needle-to-needle electrode structure until the electric field in the feed material (argon + monomer) was sufficiently high to yield electron avalanches and self-propagating streamers. The ¿corona onset criterion¿ was used to design the cold-plasma reactor. The apple was placed in a treatment chamber downstream from the activation zone (cold-plasma zone). Selected physical properties of the film were measured. Environmental scanning electron microscopy and Fourier transform infrared studies of samples were also performed to determine the presence of the film. Electromagnetic modeling was applied to the design of the cold-plasma reactor, and those results are presented in this paper.