Final ppt.controlled atmospheric storage by M ANWAR HAQ

CONTROLLED ATMOSPHERE STORAGE

1. PRESENTED BY:
M.ANWAR UL HAQ
AAMIR KHAN LAGHARI
ABDULHANAN

2. WHAT IS CAS?
TECHNICAL ASPECTS
METHODS OF CAS
WHAT ARE ITS ADVANTAGES?
 WHAT ARE ITS DISADVANTAGES?
CONCLUSION
REFERENCES
DISCUSSION

3. IT IS STORAGE OF HORTICULTURAL COMMODITIES
UNDER CONTROLLED O
2
AND CO
2
IN THE
SOURROUNDING AT BEST SUITED LEVEL OF
TEMPERATURE.
O
2
→ 5% , CO
2
→ 1% : FOR FOOD PRESERVATION
IN GENERAL O
2
LEVELS ARE REDUCED AND THE CO
2

LEVELS ARE INCREASED FOR THE FRUIT
PRESERVATION.
TEMP. DEPENDS UPON THE TYPE OF FRUIT OR VEG.

4. GAS COMPOSITION DEPENDS ON
◦AMOUNT OF PRODUCT
◦RESPIRATION RATE
◦RESPIRATION QUOTIENT
◦EXCHANGE RATE BTWEEN STORAGE ROOM AND
SOURROUNDING, STORAGE ROOM AND
SCRUBBER.

5. CA Storage MA Storage
High degree of control over gas conc.Low degree
Longer storage life Less
More expensive technology Less
Atmosphere is modified by adding gasIt is created by either actively(addition
or removal of gas) or
passively(produce generated)
Specific temperature should maintainMay or may not be maintained

6. EXCHANGE OF GASES TAKES PLACE BY MASS FLOW
◦BY VENTILATION OR LEAKAGE
◦DIFFUSION
◦PERMEABLE MEMBRANE
◦AIR FLOW CHANNELS
ATM. COMPOSITION REMAINS CONSTANT FOR
SEVERAL WEEKS WITHOUT ANY CHANGES AND IS
INSENSITIVE TO THE CHANGES IN BAROMETRIC
PRESSURE

7. AND CYCLIC FLUCTUATIONS IN THE TEMPERATURE
IN THE STORAGE ROOM.
IN SUFFICIENT AIR TIGHT ROOMS EXCHANGE CAN BE
ACHIEVED BY FIBRE-FILLED CHANNELS OF VARYING
CROSS-SECTIONAL AREA & ALSO CONNECTING THE
ROOM WITH A VESSEL CONTAINING CO
2
.

8. OPERATION USING THIS PRINCIPLE HAS BEEN
CARRIED OUT IN SEVERAL SEASONS IN A STORAGE
ROOM OF 10 m
3
CAPACITY.
 AIR COMING INTO THE STOREROOM OR BEING RE-
CIRCULATED WITHIN THE ROOM MUST PASS
THROUGH A MONITORING AND CONTROL SYSTEM.

9. OXYGEN GAS CONTROL:
TO DECREASE:
PURGING WITH NITROGEN
◦FROM LIQUID NITROGEN THROUGH AN
EVAPORATOR
◦FROM A MEMBRANE SYSTEM NITROGEN
GENERATOR
◦FROM A MOLECULAR SIEVE SYSTEM
NITROGEN GENERATOR

10. CARBON DIOXIDE CONTROL:
TO INCREASE:
DRY ICE
PRESSURIZED GAS CYLINDER
TO DECREASE:
HYDRATED LIME (USE 0.6 KG OF HYDRATED LIME TO
TREAT THE AIR USED TO VENTILATE 100 KG OF
FRUIT. AIR CAN BE DIRECTED TO PASS THROUGH A
BOX, LOCATED INSIDE OR OUTSIDE THE C.A.
STOREROOM).

11. FOR PREVENTING THE BUILDUP OF ETHYLENE, A
SIMPLE “SCRUBBER” CAN BE CONSTRUCTED AND
ADDED TO THE AIR SUPPLY LINE.
ETHYLENE CONTROL:
TO DECREASE:
POTASSIUM PERMANGANATE
ACTIVATED CHARCOAL
CATALYTIC OXIDATION

12. FRUIT TEMP. C R.H (%) O2 (%) CO2(%) TIME(day
s)
AVOCADO 7 to12 95 2 3-10 60
CHERRY 0 95 2-3 10-12 30
KIWI 0 98 2-10 4-5 210
NECTRIES _0.5 to 095 2 5 50
PEACH -0.5 to 095 2 4-5 40
PLUM 0 95 2 4 45

13.  CONSTRUCTING PLASTIC TENTS USING 20 MIL (PVC)
SHEETING SUSPENDED OVER TRADITIONAL PALLET RACKS
INSIDE A REFRIGERATED COLD STORAGE WAREHOUSE.

 SEALING HAS BEEN DONE BY CLOSING ZIPPERS ON BOTH
SIDES OF THE DOOR AND IMMERSING THE BOTTOM OF THE
DOOR AND ADJACENT FLOOR PANEL IN A TROUGH OF WATER.

THE TROUGH IS MADE USING A 6 INCH DIAMETER PVC PIPE,
WHICH ALSO ALLOWS SUPPLY AND SAMPLING GAS LINES AND
TEMPERATURE PROBE WIRING TO PASS INTO THE TENT. ALL
SEAMS AND JOINTS OF THE TENTS ARE HEAT-WELDED.

14. CONTROLLED ATMOSPHERE STORAGE OF PALLET
LOADS OF PRODUCE IS ALSO POSSIBLE USING A
SEMI- PERMANENT SET-UP FOR CREATING A GAS-
SEAL.
ANY NUMBER OF PALLETS CAN BE ACCOMMODATED
INSIDE A PLASTIC TENT MADE USING 7 TO 8 MIL
POLYETHYLENE SHEETING. A BETTER GAS BARRIER
AT THE FLOOR CAN BE OBTAINED BY LAYING A
SHEET OF 4 TO 5 MIL POLYETHYLENE ON THE FLOOR
AND COVERING IT WITH WOOD PANELS.
THE SEAL IS THEN MADE BY JOINING THE TENT
PLASTIC WITH THE FLOOR PLASTIC (USING TAPE).

15. TO REGULATE CO
2
LEVELS IN A CA ROOM, ONE
OF THE SIMPLEST METHODS IS THE
HYDRATED LIME (CALCIUM CARBONATE)
CA(OH) 2 “SCRUBBER”. THE SCRUBBER IS
CONSTRUCTED USING AN INSULATED AND
AIRTIGHT PLYWOOD BOX LOCATED OUTSIDE
THE CA ROOM. THE BOX SHOULD CONTAIN
ENOUGH LIME FOR THE ENTIRE STORAGE
PERIOD, BUT NEW LIME CAN BE ADDED IF CO
2

ABSORPTION DROPS.

16. THE CO
2
AND HYDRATED LIME REACTS IN A 1:1
RATIO TO FORM LIMESTONE AND WATER.
LIME WITH A SMALLER PARTICLE SIZE (FINE
MESH) IS MORE EFFICIENT AT REACTING WITH
CO
2
THAN LIME WITH A COARSE MESH. THE
FOLLOWING WILL MAXIMIZE THE
EFFECTIVENESS OF YOUR SMALL-SCALE
SCRUBBER:

19. RETARDS SENSCENE AND FURTHUR
DETERIORATION OF FRUIT.
QUALITY RETAINS OF FOOD MATERIALS.
SHELF LIFE INCREASES.
RIPENING IS DELAYED AS ETHYLENE IS
SCRUBBED FROM THE STORAGE AIR. THE
SHELF LIFE OF BANANAS UNDER THESE
CONDITIONS IS FOUR TO SIX WEEKS AT
AMBIENT TEMPERATURES.

20. CONTROL OF SOME PHYSIOLOGICAL
DISORDERS, PATHOGEN, AND/OR INSECTS.
PRESERVED SO PROLONG STORAGE.
LITTLE OR NO CHEMICAL PRESERVATIVES.
ASTHETIC APPEAL

23. IT IS QUITE EXPENSIVE.
TEMP. CONTROL REQUIRED.
DIFFERENT GAS COMPOSITION FOR EACH
TYPE OF PRODUCT.
SPECIAL EQUIPMENT AND OPERATOR
TRAINING REQUIRED.
ONCE PACK OPENS OR LEAKS THE BENEFITS
ARE LOST.

24. INCREASED PACK VOLUME HAS IMPACT ON
TREANSPORT AND COST.
PRODUCT SAFETY REQUIRED FOR SOME
FRUIT.

25. CONTROLLED OR MODIFIED ATMOSPHERE
STORAGE SHOULD BE USED AS A
SUPPLEMENT TO, AND NOT AS A SUBSTITUTE
FOR, PROPER TEMPERATURE AND RELATIVE
HUMIDITY MANAGEMENT.

26. Thompson, A.K. 1998. Controlled Atmosphere
Storage of Fruit and Vegetables, CAB
International, UK.
Gormley, T.R., 1985, Chilled Foods, the State of
the Art, Elsevier App. Sc i. , London, New York.