Its about CA and MA storage of food material, beneficial effects of CA & MA etc.

1. Controlled Atmosphere and Modified
Atmosphere Storage
By
Nungleppam Monica
Food Process Engineering
Indian Institute of Technology KharagpurIndian Institute of Technology Kharagpur

2. CONTROL ATMOSPHERE and
MODIFIED ATMOSPHERE
 Control atmosphere (CA):
 generally refers to decreased O2 and increased
CO2 concentrations, by a precise control of the
gas composition.
 Modified atmosphere (MA):
 is used when the control of the storage
atmosphere is not closely controlled, such as in
plastic film packaging.

3. DIFFERENCE
MA:
Gas composition is modified initially and it changes
dynamically depending on the respiration rate of
produce and permeability of film or storage structure
surrounding the produce
CA:
Gas atmosphere is continuously controlled throughout
the storage period

4.  Scrubbers are
used in controlled
atmosphere storage
to absorb the extra
amount gases
present inside the
packaging
material.
Scrubbers

5.  Air contains:
 21% O2
 0.03% CO2.
 Modification of the atmosphere:
 O2 ↓
 CO2 ↑
 Increased the shelf-life of perishable foods

6. Main crop
potatoes
Celery
Lettuces
Carrots
Leeks
Soft fruit
Asparagus
Broccoli
Spinach Banana Mushroom
Respiration rate HighLow
Short
Long
Shelf
Life

7. Minimum O2
concentration
tolerated(%)
Commodities
0.5 Tree nuts,dried fruits,and vegetables
1.0 Some cultivars of apples and pears,brocolli,mushroom,garlic,onion,most
cutor sliced(minimally processed)fruits and vegetables
2.0 Most cultivars of apples and
pears,kiwifruits,apricot,cherry,nectarine,peach,plum,strawbery,papaya,pi
neapple,olive,cantaloupe,sweet corn,green
bean,celery,lettuce,cabbage,cauliflower.brussels sprouts
3.0 Avocado,persimmon,tomato,pepper,cucumber,artichoke
5.0 Citrus fruits,green pea,asparagus,potato,sweet potato
Table 1: Fruits and Vegetables classified according to their
tolerance to low O2 concentrations
Fruits and vegetables differ in their tolerance to low O2 and to
high CO2 concentrations.

8. Table 2: Fruits and Vegetables classified according to their
tolerance to elevated CO2 concentrations
Maximum CO2
concentration
tolerated(%)
Commodities
2 Apple(Golden Delicious),Asian pear,European
pear,apricot,grape,olive,tomato,pepper(sweet),lettuce,endive,Chinese
cabbage,celery,artichoke,sweet potato
5 Apple(most
cultivars),peach,nectarine,plum,orange,avogado,banana,mango,papaya,
kiwifruit,cranberry,pea,pepper(chilli),eggplant,cauliflower,cabbage,Bru
ssels sprouts,radish,carrot
10 Grapefruits,lemon,lime,persimmon,pineapple,cucumber,summer
squash,snap bean,okra,asparagus,broccoli,parsley,leek,green onion,dry
onion,garlic,potato
15 Strawberry,raspberry,blakberry,blueberry,cherry,fig,cantaloupe,sweet
corn,mushroom,spinach,kale,Swiss chard

9. Table 3: Controlled atmosphere conditions for some fruit species
Species Best
Temp.
(°C)
RH(%) O2 (%) CO2 (%) Time
Avocado 7 90 2-3 3-10 2 months
Cherry 0 95 3-10 10-12 30 days
Kiwi 0 98 2 4-5 7 months
Nectarine -0.5 95 2 5 50 days
Peach -0.5 95 2 4-5 40 days
Plum 0 95 2 5 45 days

10. Table 4: Controlled atmosphere conditions for some vegetable
species

11. BENEFICIAL EFFECTS OF PROPER
CA STORAGE:
 delayed softening and mealiness (apples, pears,
tomatoes),
 delayed toughening (asparagus),
 chlorophyll retention (apples, pears, leaf vegetables),
 insect control- O2(< 1%) and/or elevated CO2(40 to
60%)

12. BENEFICIAL EFFECTS OF PROPER
CA STORAGE:
 inhibition of the browning of cut surface(cut fruits
and vegetables),
 better flavour retention (pineapple, cabbage),
 reduction of disorders and decay (berries),
 Higher nutritional value after storage (vitamin C).

13. DETRIMENTAL EFFECTS OF CA
(above or below optimum composition
for the commodity):
 May cause irregular ripening of fruits (banana, mango,
pear, and tomato, at O2 below 2%, CO2 above 5% for >
1 month).
 May cause certain physiological disorders.
 May enhance anaerobic respiration and development
of off-flavors.
 May cause susceptibility to decay.

14. Table 5: Examples of CA injury

15. STORAGE DISORDER
Low O injury₂
Internal CO injury₂
(Brown heart)
Low temp. breakdown
External CO injury₂

16. DISADVANTAGES
 It is quite expensive.
 Temp. control required.
 Different gas composition for each type of product.
 Special operation and operator training required.
 Once pack opens or leaks the benefits are lost.

17. RECENT DEVELOPMENTS IN CA
STORAGE
 Recent improvements include maintaining CA
during transport in refrigerated marine containers.
 CA transport of banana permits the harvest at a more
fully-mature stage.
 In addition to CA, there is also a continuing increase
in the use of plastic films and MAP.

18. MODIFIED ATMOSPHERE
PACKAGING (MAP)
 Modified Atmosphere Packaging (MAP) involves the
modification of the head space gas in a package in
order to prolong the shelf life of the product it
contains.
 The greatest use of MAP is for fresh-cut products (to
maintain 2-5% O2 and 8-12% CO2).
 It is possible to improve gas control in MAP by
adding absorbers of ethylene, carbon dioxide and
oxygen.

19.  O absorber:-₂ Iron powder is used commercially as
the active ingredient. Ex. FeO, Fe O , Fe O₂ ₃ ₃ ₄
 CO absorber:-₂ Lime(freshly hydrated high
calcium lime (Ca(OH) ),activated charcoal,₂
magnesium oxide)
 Ethylene absorber:- Potassium permanganate,
builder clay powder, hydrocarbons, silicones

20. TWO TYPES
Active modification
The atmosphere is modified by pulling a slight
vacuum and replacing the packaging atmophere within
the desired gas mixture.
Passive modification
Modification is achieved by respiration of
commodity within the package and depends on the
characteristics of the commodity and the packaging
film.

21.  Passive modification
 Product packaged with selected film
 Desired atmosphere develops naturally over time
 Takes longer to achieve desired atmosphere in package
 Active modification
 Displace or remove gases in package
 Replace with mix of desired gases and seal
 Better shelf life is achieved with Active Modification

22. CONCLUSIONS
 A strong preservation of quality and nutritional value
is demonstrated by CA storage with a lowering of O2
and an enhancement of the CO2 concentrations. This
results in:
 better quality after storage
 a longer storage period
 a longer shelf-life period after storage
 a higher nutritional value after storage(vitamin C)
 a more environmental friendly storage(no
postharvest chemical treatments against scald are
needed).

23. Thank you