Precooling removes the field heat. Reduction in rate of respiration and ethylene (C2H4) liberation. Reduction the chance of fungal infection. Reduction of water loss from the harvested produce. Prevent quality loss due to softening. Restriction of the enzyme activities. Prevent quality loss due to softening. It reduces energy required for cold storage. It provide Marketing flexibility.

1. MANGO FRUIT PRECOOLING
TECHNIQUES
Welcome to my presentation
By Samar Biwas Roll No:513

2. Mangoes are juicy stone fruit (drupe) from
numerous species of tropical trees belonging to
the flowering plant genus Mangifera, cultivated
mostly for their edible fruit.
“The king of the fruits,"
mango fruit is one of the
most popular, nutritionally
rich fruits with unique flavor,
fragrance, taste, and heath
promoting qualities, making
it numero-uno among new
functional foods, often
labeled as “super fruits."

3. Additionally, mango peel is also rich in phytonutrients, such as the pigment
antioxidants like carotenoids and polyphenols.
Health benefits of Mango fruit
Mango fruit has been found to protect from colon, breast, leukemia and
prostate cancers.
Mango fruit is rich in pre-biotic dietary fiber, vitamins, minerals, and poly-
phenolic flavonoid antioxidant compounds.
Mango fruit is an excellent source of Vitamin-A and flavonoids like β-
carotene, α-carotene, and β-cryptoxanthin.
Consumption of natural fruits rich in carotenes is known to protect from
lung and oral cavity cancers..
Fresh mango is a good source of potassium. Potassium is an important
component of cell and body fluids that helps controlling heart rate and
blood pressure.

4. Scenario of Postharvest Loss of
Bangladesh
In Bangladesh, The major post-harvest losses of
mango from farmer to local market due to improper
handling, transportation and grading, packaging and
storage.
The losses found at Mohajon, Foria, Arotder, Bepari,
Wholesaler and Local/Supermarket were found 11%,
1%, 5%, 3%, 12% and 2%, respectively.
Total average loss is found as much as 34%.
If 50% loss of mangoes is reduced through
intervention of appropriate technologies during
transportation and storage, the country may save
about Taka 200 cores in a year.
Losses at Mohajon and wholesaler level can be
minimized by precooling techniques.

5.  Bangladesh has potentiality to
increase its export of mangoes
through proper postharvest
technology.
 The physiological and biochemical
changes during respiration and
transpiration are influenced by
environmental factors like
temperature, ethylene, O2 and CO2
concentration.
 In general these biological activities
causes decline in quality of the
produce and limit its shelf life.
 Losses due to respiration and
transpiration may be controlled by
precooling.
Mango export potentiality in Bangladesh

6. Why Precooling needed?
 Precooling removes the field heat.
 Reduction in rate of respiration and ethylene (C2H4)
liberation.
 Reduction the chance of fungal infection.
 Reduction of water loss from the harvested produce.
 Prevent quality loss due to softening.
 Restriction of the enzyme activities.
 Prevent quality loss due to softening.
 It reduces energy required for cold storage.
 It provide Marketing flexibility.

7. Cooling temperature 0 – 14°C
Reduce temperatures via
different means
Principle of precooling
of Mango Pre-cooling
techniques
1. Air cooling
– Room cooling
– Forced air cooling
2. Hydro cooling
3. Ice cooling
– Top icing
– Liquid icing
– Individual package icing
4. Vacuum cooling
5. Evaporative cooling
Direct cooling
Heat sink medium,
eg. Cold water ice
and mixture
Heat out
Indirect cooling
Heat sink medium,
eg. Cold air, cold
metal
Heat out

8. Hydrocooling
The flow of chilled water over produce.
Disadvantages
 Limited to produce that are not sensitive
to wetting
 Not energy efficient (20-40% efficiency)
Critical point
 Good water sanitization practice
 Proper packaging
Figure : Pictorial View of the
Cold Water Bath

9. Liquid Nitrogen Augmented
(Initial Cool Down) Air cooling
Precooling of mangoes with liquid
nitrogen was carried out in the setup
as shown in. Liquid nitrogen was
employed as the cooling medium only
for the initial cool down of the system
i.e. till the temperature for storage was
achieved (12oC). Once this
temperature was attained, flushing of
liquid nitrogen into the chamber was
stopped and the storage temperature
was thereafter maintained using a
mechanical refrigeration system till
the end of the storage period.
Figure : Pictorial View of
the Lab Scale Cooling Air
Chamber

10. Forced-air cooling
 Fan assisted room-cooling.
 The fan pulls cool air
through packaged produce
and forces the hot air to
leave the package.
 Cooling rate depends on
temperature and the air
flow rate.
 75 – 90% more efficient than
room cooling. Fig. Forced-air cooling
Chamber

11. Ice-cooling
• Ice continues to absorb heat as
it melts
• Suitable for
– Produce with high respiration
rate
– Dense product or palletized
packages
• Relatively energy efficient
– 1 lb of ice cool 3 pounds of
produce (85°F to 40°F)
Maintain low temperature during
transportation
Fig. Ice-cooling chamber

12. Vacuum cooling
Vacuum around the produce
causes water to evaporate
rapidly thus reducing the
temperature
Vacuum is created by putting
produce in the metal container.
Then, the air is evacuated
• Disadvantage: wilting (if
overdone)
Hydro vacuum cooling
– Spray water onto the
produce before vacuum process
Fig. Vacuum cooling
chamber

13. Evaporative cooling
Misting/wetting in the
presence of dry air stream
(RH<65%) to cause
evaporation
Effective and inexpensive
means of providing low
temperature & high RH
conditions
Good for warm season
crop such as tomatoes,
pepper, cucumbers or
eggplant
Fig. Evaporative
cooling chamber

14. Conclusion
Mangoe fruits can be precooled with different techniques such as liquid
nitrogen augmentation of a mechanical refrigeration system, hydrocooling,
or air cooling.
These are unique commonly employed precooling techniques.
It was observed that hydrocooling was a faster technique than air cooling,
however liquid nitrogen augmentation helped to reduce the time required
for air cooling by 20%.
The ripening indices like colour development and firmness of the ripened
fruit indicated that the liquid nitrogen augmented precooling system
employed did not adversely affect the ripening of the fruit.
The physicochemical studies such as firmness, retention of aroma indicated
that the precooled fruits were comparable as far as the technique employed
was concerned.
It could be concluded from this study that liquid nitrogen systems can be
successfully used for precooling of mangoes if the design of the system
ensures no direct contact between the fruit and the cryogenic liquid.

15. Thanks all of you
Any query?