Effect of O-2 and CO2 partial pressure on selected phenomena affecting fruit and vegetable quality

It is likely that from the time of the Roman Empire and perhaps before, peo ple involved in the storage of plant material as food recognized that atmos pheric modification can provide some benefit in improving storability. Howe ver, active, commercial modification of the atmosphere for the preservation of fresh fruit and vegetables dates to the early part of this century. Ear ly successes with apple fruit has lead to the attempt to apply modified atm ospheres to a wide range of commodities. Responses to atmospheric modificat ion are found to vary dramatically among plant species, organ type and deve lopmental stage and include both unwanted and beneficial physiological resp onses, Desirable responses include a reduction in respiration, a reduction in oxidative tissue damage or discoloration, a reduction in the rate of chl orophyll degradation and a reduction in ethylene sensitivity with the conco mitant reduction in the rate of ripening and other ethylene-mediated phenom ena. Undesirable responses have included the induction of fermentation, the development of disagreeable flavors? a reduction in aroma biosynthesis, th e induction of tissue injury and an alteration in the makeup of microbial f auna. The physiological bases for some of these responses to elevated CO2 a nd reduced O-2 are discussed. (C) 1999 Elsevier Science B.V. All rights res erved.