Bananas and Food Security - Bioversity International

Afrique - Africa : A.O. Olorunda
Managing of green life and shelf life
by optimisation of environmental conditions
Another way to extend the green life of banana and plantain is to optimise the
environmental conditions. Manipulation of the environmental conditions is usually
performed to lower respiration and growth of decay organisms without inducing
physiological injury. Temperature and relative humidity are factors generally given
primary consideration. Light and atmospheric conditions are other factors that affect
green life and shelf life. Work done by Olorunda et al. (1977, 1978) has shown that
banana and plantain like most tropical fruits and vegetables are sensitive to chilling
injury. This seriously limits the scope of reduced temperature in extending green life. In
the same work it was observed that the peel of the banana fruit soon blackens when
stored at chilling temperature and the fruits fail to ripen normally even after they have
been returned to ambient conditions.
Another area that we have explored to a very large extent in our banana and plantain
research project is the use of controlled or modified atmosphere storage. Here the
oxygen concentration in the bio-environment of the plantain is reduced in order to
retard ripening. This technology is more or less routine in the banana trade where fruit
is generally harvested mature green and subsequently ripened according to need by
introducing ethylene gas at between 20-200 microlitres into ripening chambers (Marriot
and Lancaster 1983, Thompson and Burdon 1995). We have successfully used modified
atmospheres to delay ripening in plantain under tropical ambient conditions (Olorunda
1976, Ndubizu 1976) by using sealed polyethylene bags containing sawdust impregnated
with saturated potassium permanganate solution. This method has now been scaled up
to accommodate up to half a ton of plantain bunches by using a modified atmosphere
structure developed in our department (Orishagbemi 1987).
Management of green life by the application of additives
Green life and shelf life extension can also be achieved by the application of food
additives in the form of chemical sprays, dips, or ionising radiation. Chemicals, sprays or
dips are applied to regulate growth and development, prevent attack from pests and
control microbial or physiological events or disorders during post harvest handling. Work
done in our laboratory by Olorunda and Aworth (1984) on the effect of Tal-prolong, a
surface coating agent, on the green life and quality attributes of plantain showed that
relative to untreated fruits, colour development i.e. ripening was delayed by up to eight
days. The products obtained from the treated plantain after they eventually ripened were
comparable to those from untreated plantain. A similar result was obtained in our work
with semper fresh, another surface coating agent (Chukwu et al. 1995).
Management of green life and shelf life through
selection and breeding
The rate at which banana and plantain ripen is significant in determining how long the
fruits remain usable for specific methods of processing/cooking. The selection of
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