| Summary: | 碩士 === 國立中興大學 === 園藝學系 === 86 === The objectives of this experiment were to investigate the
physiological changes of wax apple after low temperature storage
, the temperature and time requirment for in or out of season
fruits ; the suitable treatment for the prevention of cold
injury and the quarantine procedure of wax apple for export.The
visible symptoms of chilling injury of wax apple fruits include
surface pitting , color-fading , water soaking of pulp , mold
infection and decay of fruits . Results indicated that if fruits
were stored at 0℃ , 5℃ or 10℃ , chilling injury would result
. Most suitable storage temperature were 15℃ , 20℃ or 25℃ ,
but decay rates increased following enhanced storage temperature
.Wax apple fruit while stored at a tolerable low temperature for
a certain period of time and then transferred to an environment
of 25℃ , respiration and ethylene production rates were raised
. Low temperature plus long period of storage would cause
irreversible damage to fruits by stimulating and maintaining a
high respiratory rate .Fruits stored at 0℃ and 5℃ for 9 days
exhibited a similar trend of raised temperature after cold
storage . The stimulated respiration rate was found closely
correlated with degree of chilling injury . Ethylene production
was likewise enhanced , but the correspouding production rate
failed to show a linear pattern like respiration . Thus , it is
suggested the respiration rate is a more useful index of
chilling injury than ethylene . Polyethylene bag packing , hot
water and precooling treatment are some of the routine
procedures employed before low temperature storage .Wax apple
fruit wrapped up in a PE bag significautly reduced deterioration
rate , and maintained other commercial qualities such as color ,
sugar content and firmness. Those without PE bag suffered water
loss which could reach 2﹪total weight , consequently , with
shrinking peels . A 5﹪water loss could cost fruit it''s firmness
and other commerial value.Dipping fruits in hot water ( 55℃ )
for 3 min , could temporarily delay fruit detrioration . Hot
water treatment ( 49℃ ) for 20 to 30 min caused scald on the
skin and softening of fruit. Precooling had no effect on
prevention of fruit water loss like PE bag packing .The present
day quarantine required that wax apple be perfused with 50﹪
CO2+50﹪N2 or 100﹪N2 . Decay rate increased simutaneously with
ethylene gas treatment , and colorfading and reduction in
firmness are some of other related side effects . High CO2
concentration brought about brown specks on the fruit. Air
treatment was found without such defects , and should be
considered as replacement.Apart from the fruit , leaves of wax
apple has been tested for it''s response to low temperature .It
was found that the fully unfurled young leaves were most
sensitive to chilling injury , and pattern of response was
similar to the fruit. It is a practical measure to test the
overall tolerance to low temperature during a cold spell in
winter befor the come into bearing .
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