MATHEMATICAL-MODELING OF GAS CONCENTRATION PROFILES IN MODIFIED ATMOSPHERE BULK PACKAGES

A three-dimensional mathematical model was developed to predict gas di stribution as a function of time inside a perforation-generate modifie d atmosphere bulk package using the principle of diffusion in a ternar y gas mixture. Product and air space layers in the package were consid ered. The model incorporates simultaneous oxygen consumption, carbon d ioxide generation and porosity in the product layer An implicit-explic it finite difference numerical technique was used to solve the transie nt three-dimensional equations. The mathematical model closely predict ed measured gas concentrations in different types of packages. The res ults show package CO2 concentration increased; whereas, O-2 concentrat ion decreased with increasing distance from the perforation. Higher ga s concentration gradients were obtained in packages with thin air spac e thickness. Thus the effective distance from the perforation is an im portant parameter for gas concentrations in perforation-generated modi fied atmosphere bulk package.