Freezing is one of the oldest and most commonly used means of food preservation. SS Engineers Freezing food technology preserves it from the time it is prepared to the time it is eaten

1. Technology of
Frozen Food
TECHNOLOGY OF
FROZEN FOOD

2. The effect of refrigeration on foods is two folds :
A decrease in temperature results in a slowing down of chemical,
microbiological and biochemical processes. At temperature below 0C
water freezes out of solution as ice, which is equivalent in terms of water
availability to dehydration or a reduction
2

3. 3
Effect of freezing on tissues:
Foods do not have sharp freezing points, but
freeze over a range of temperature depending
on the water content and cell composition.
Rapid freezing, and storage without wide
fluctuations in temperature, lead to small
intracellular ice crystals and maintenance
tissues with minimum damage to cell
membranes.

4. Effect on freezing on microorganisms
The growth of microorganisms in foods at temperatures below about –12oC
has been confirmed. Thus storage of frozen foods at about –18oC and below
prevents microbiological spoilage. Although microbial numbers are usually
reduced during freezing and frozen storage (except for spores), frozen foods
are not sterile and can spoil as rapidly as the unfrozen product if temperature
are sufficiently high and storage times at these temperatures are excessive.
4

5. 5
Vegetable Preparation Blanch/Freeze
Asparagus Wash and sort by size.
Snap off tough ends.
Cut stalks into 5-cm lengths.
Water blanch:
Steam blanch:
Beans Wash and trim the ends.
Cut if desired.
Water blanch:
Whole: 3 min.
Cut: 2min.
Beets Wash and remove the tops leaving
2.5 cm of stem and root.
Cook until tender: 25-30 min
Cool promptly, peel, trim.
Cut into slices or cubes and pack.
Broccoli Wash and cut into pieces. Water blanch:
Vegetables
Freezing
Guide:

6. 6
Cabbage Wash and cut into wedges. Water blanch: 3min
Steam blanch: 4min
Carrots Wash, peel and trim.
Cut if desired.
Water blanch: 5 min.
Cauliflower Discard leaves; steam and wash.
Break into flowerets.
Water blanch Whole: 5min
Steam blanch Whole: 7 min.
Corn Remove husks and silks.
Trim ends and wash.
Water blanch:
Whole: 5 min.
Greens Select young tender greens.
Wash and trim the leaves.
Water blanch: 2min
Steam blanch: 3min
Vegetables
Freezing
Guide:

7. 7
Herbs Wash. No heat treatment is needed.
Mushrooms Wipe and damp with paper towel.
Trim hard tip of stems.
Sort and cut large mushrooms.
May be frozen without heat
treatment.
Peas Shell garden peas. Water blanch: 1-1/2 min.
Steam blanch: 1-1/2 min.
Peppers Wash, remove stems and seeds. Freeze whole or cut as desired. No
heat treatment is needed.
Potatoes Peel, cut or grate as desired. Water blanch:
Whole: 5 min.
Pieces: 2-3 min.
Vegetables
Freezing
Guide:

8. Big concept
Know more about frozen
food processing technology
and how it works and learn
more about the ROI
8

9. Methods of freezing Freezing techniques include :
9
The use of cold air blasts or other low temperature gases coming in
contact with the food, e.g. blasts, tunnel, fluidized bed, spiral, belt
freezers. Indirect contact freezing, e.g. plate freezers, where packaged
foods or liquids are brought into contact with metal surfaces (plate,
cylinders) cooled by circulating refrigerant (multi-plate freezers).Direct
immersion of the food into a liquid refrigerant, or spraying liquid
refrigerant over the food (e.g. liquid nitrogen, and freon, sugar or salt
solutions).

10. The freezing method chosen for each product will depend on :
product quality and freezing rate
desired Type and shape of product,
package, etc.
Flexibility required in freezing
operations.
Costs of freezing for alternative
techniques.
10

11. 11
Freezing of fruits and vegetables
Providing storage temperatures do not exceed the minimum for
microbial growth for extended periods of time, frozen food quality
deteriorates principally as a result of physical, chemical, and biochemical
changes.

12. 12
packing of fruits in dry sugar or sugar syrups to increase freezing rate
and reduce browning, by reducing access of oxygen to the fruit. Changing
the pH of some fruits to decrease browning reactions.
Enzymic change are particularly important causes of quality changes in
fruits, and these enzymes must be inactivated or inhibited if satisfactory
quality is to be retained. During freezing and frozen storage the
concentration of cellular constituents including enzymes and their substrate
increase, hence rates of enzymic activity in frozen tissues can be
appreciable, despite the low temperatures

13. 13
Quality retention in frozen foods
The principal factors that effect the retention of quality in frozen foods
are :the quality of the raw material used (variety, maturity, suitability
for freezing and frozen storage).The treatment given prior to freezing
(blanching, SO2, ascorbic acid).The freezing method and freezing rate.
The storage temperature, and temperature fluctuations. The storage
time The humidity of the storage environment, especially food is
unpackaged The nature of packaging materials.

14. 14
Quality deterioration occurs principally as a result of :
Changes in colour (loss of natural colour constituents, e.g. chlorophil
pigments, development of off colour)Changes in tecture (loss of cloud
destruction of gels, protein denaturation, toughening)Changes in flavour
(loss of natural flavour, development of off-flavour, rancidity)Changes in
nutrients, such as ascorbic acid in fruits and vegetables, unsaturated lipids,
essential amino acids.

15. “
Unsweetened packs are generally prepared by using tray
packs in which a single layer of prepared fruit is spread
on shallow trays, frozen, and packaged in freezer bags
promptly.
15
Tray Packs

16. 16,124Clients
Whoa! That’s a big number, aren’t you proud?
16

17. Methods of freezing Freezing techniques include :
17
The use of cold air blasts or other low temperature gases coming in contact
with the food, e.g. blasts, tunnel, fluidized bed, spiral, belt freezers. Indirect
contact freezing, e.g. plate freezers, where packaged foods or liquids are
brought into contact with metal surfaces (plate, cylinders) cooled by circulating
refrigerant (multi-plate freezers).Direct immersion of the food into a liquid
refrigerant, or spraying liquid refrigerant over the food (e.g. liquid nitrogen, and
freon, sugar or salt solutions).

18. Thanks!
Any questions?
You can find me at:
itssengrindia@gmail.com
www.ssengrindia.com
18
👍