Post harvest diseases fruits and vegetables - Xavier University ...

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
Means for Maintaining Host Resistance 13 5
the anti-ethylene treated bags. Ethylene-mediated ripening changes were
markedly delayed, suggesting that MAP, in combination with the potent
antagonist of ethylene action, may serve as a technology for long-distance
transport of green bananas without refrigeration (Jiang et al., 1999).
For food products other than fruits and vegetables, developments in
'smart' packaging include films impregnated with anti-microbial
compounds that actively retard the development of harmful
microorganisms during storage. Church (1994) indicates that changes in
the gas composition within the package during storage may provide an
indirect indication of the condition of the product. Therefore, labels which
change color in response to the concentrations of CO2, O2 and other gases
in the atmosphere could serve as indicators to detect damage in the
packaged product.
With the development of polymeric films suitable for the providing the
advantages of MAP, and the increased choice of packaging materials, the
number of products that can benefit has increased. Today, thanks to the
introduction of the 'smart packages', the in-package atmosphere offers
the potential to extend the technology to a wider range of products and
markets.
4. HYPOBARIC PRESSURE
Hypobaric or low-pressure (LP) storage, similarly to modified or
controlled atmosphere storage, is designed to delay ripening and
senescence processes in fruits and vegetables, and to extend their
postharvest life. In this procedure, the commodity is maintained in a
vacuum-tight and refrigerated container, held at subatmospheric
pressure and continually ventilated with humidified air at relative
humidity (RH) of 80-100% (Burg, 1990; Dilley et al., 1982). With the
reduction in the atmospheric pressure beneath 760 mm Hg, the oxygen
level in the atmosphere is reduced. Under continuously ventilated partial
pressure, CO2, ethylene and various volatile by-products of metabolism
rapidly diffuse out of the commodity and are flushed from the storage
chamber. As a consequence of the low partial pressure of O2 and the low
levels of ethylene in the atmosphere, ripening and senescence of fresh
fruits and vegetables are delayed and storage life is extended.
Following the disclosure of hypobaric storage technology by Burg and
Burg in 1966, extensive investigations have been conducted with a wide
range of fruits and vegetables (Laugheed et al., 1978). Although the
high-RH conditions under LP storage appear ideal for fungal growth and
decay development, several studies report on the beneficial effects of the
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