Introduction
Fresh sweet corn (Zea mays L.) is a perishable
food product prone to fast postharvest deterioration
caused by kernel desiccation, loss of sweetness,
husk discoloration and development of
pathogens. Keeping cobs in a modified atmosphere
(MA) enriched with CO2 (5–10 kPa) may
reduce the mold growth and inhibit sugar and
chlorophyll loss. On the other hand, concentrations
of CO2 above 10 kPa and:or O2 below 2 kPa
spoil the product due to off-flavor and odor development
(Saltveit, 1997).
Sweet corn is exported from Israel to Europe
within retail cardboard trays overwrapped with
stretch polyvinylchloride (PVC) film. The PVC
wrap reduces moisture loss from kernels. The MA
is formed inside the packages as a result of inter-action between produce respiration and barrier
properties of packaging material. However, the
relatively high permeability of PVC film for CO2
does not allow a fungistatic CO2 concentration to
accumulate, sufficient for disease control during
shipment. Substituting the PVC wrap with less
permeable polyolefin stretch films improved the
keeping quality of sweet corn due to elevated CO2
accumulation (Aharoni et al., 1996). On the other
hand, the use of relatively high-barrier films for
retail packaging may increase the risk of O2 depletion
and off-flavor development after transferring
packages from cold storage to non-refrigerated
stores (shelf-life), since elevated temperature enhances
produce respiration to a greater extent
than it increases the permeability of regular packaging
films