7 - part

thoroughly. Tolerance to high tempcratures
also needs to be studied. Many tropical and
subtropical fruits develop high temperature
injury before being shipped to market. The
high temperatures fruit may encounter may
be in the field, if the fruit Licks proper protection
from the sun, or iipi
ventilation.
-skaesor stacks with poor
Relative humidity atisO hocl a great effect
on the postharvest life ird q(litli1v of frtit'
'1 fny fruits rX uire hiih !0eliv . I hum idity
(90 9T) ).bit otherS iAly rvJii.le slightly
lower huiiiridit',/ Boios require higher
humidity when in,, fiutt is qjirot. but se
humridity when the fruit is; il, .I UderIta IlidgI
the requirement lid tolcrkor r e! frti
to hnrnidiTy 1.,ioport.ilt I 1e tilwhich
cIIno t tolerate thih imriilty oc,.toti
VIoter cOnollsetl'Ot on :, tC, i :tlt) :,t be
Intpt to clvii ii 'am Vig'
out :Jijyil r, side Ipples an"l talr
a po u iv ,i n :nttiolled atinosphere
(CA\) -Inl oci-. i. , ,l(A) *t .
Some hlt.,s t(.:..rj',! ,; iv to CA ,)IMA
evern at relatively igh o .it res. anana
is one example of ,oshi fiuit: ' Eich
fruit has its beneficial i wqut' o' 0 1nd CO
cornbinations, and its i i-s levels of low
0 and high CO Yh,.otjur ou:; levels; may
chlange with tentpcelature, dilation of exposure,
and the physiological 'gie oif th. fruit. This
kind of inforniation i.;usefli in developing
handling method: particu orly if CA o, MA
storage or packwgirg is to be considered. The
imlormation will also be useful for identifying
disorders caused by low 0- of high CO, , or a
combination of the two, if the fruit is accidentally
exposed to such conditions. In addition to 0
and CO, concentrations, ethylene accumulation
in the storage atmosphere -,n have a significant
effect otn the postharvest life of fruit : '. The
sensitivity of fruit to ethylene depends on
the species and varieties concerned, and the
physiological age of the fruit, as well as
on the temperature ane the O and CO,
concentrations.
.
.3
Many fruits, such as avocado, banana,
mango, and papaya, are often harvested at the
'mature green" or artially ripe stoge and ripened
after harvest. The ripening treatment, such as
ethylene application, and the ripening environment
they recieve, including temperatire, humidity,
and O and CO, concentrations, will affect the
quality of the fruit after it ripens. The currently
recommended best ripening temperatures for
various fruits differ slightly according to the
species, but are rn o tlv within the range 16- 27 C'>
Howe~ar, there isscnwe evidence that the best
ripening temperature of any one kind of fruit
may vary accolding to the { owing conditions,
rd therefore reos;sessrient of the temperature
mal I;lVy he n'ese for different Drod uct ion
l,: .;
riMoti,' putllished resarch papers (iive only
the bet:;tempeltute, humnidity, or controlled
atmosphere for each fruit. Thi., intormation i:
often riot sufficient fol : tIast.i dJppi.c [lull.
Too often the b'st [s)itition,; are difficult to
obtain ()Iecono[ically unfeasibLe There are
occa;sion:, wtien the s;econd lest or third best
condition is mo,;t practical. Therefore, resetrchers
should be encouraged to collect an report data
covering a wid, i tote ,t cod itions, and include
harmful as well as beineficil ones.
R-sistance to Mechanical St.res
Mecha nical rlaniage, such as btuises, cuts,
breaks, defoi nation, and invisible wound; which
lead to funqal :itt,ck and )Iiys:o'ogical disorders,
is a major cause of postharvest losses of fruit.
Damage may occur dtiring harvesting, hauling,
handling, transpo tation or marketing. It is easy
to blame workers for noi being careful enough,
or simply to tell them to be more careful in
harvesting and handling fruit. However, we .aeed
more information on how much care is needed
for each kind of fruit. We sometimes hear the
suggestion that fruit should be handled as carefully
as eggs. Is it really necessary, or is it in fact
sufficient, to handle fruit as if it were eggs?
The answer might be negative. Probably some