In this presentation, the Food Engineering unit operation blanching has been covered.

1. Your University Name
Assignment on
Course Title : PROCESSING TECHNOLOGY
OF FRUITS AND VEGETABLES
Course Code : XXXXX
Presented by:
<your name>
Reg : <your Reg>
Section : XXXXXX

2. Blanching
What is Blanching ?
In food Engineering blanching is a Unit Operation. In order to preserve
food blanching is done. That is why it is also called Preservation Tanique.
Hot water and steam are the most commonly used heating media for
blanching.

3. Purpose of Blanching
Inactivating
enzymes
Prevents loses
Food
Color
Texture and
Floured
Helps
Vitamin Loses
Removes
Microorganism
from Food
Products
Remove Surface
dirt. It gives
more freshness
of Food

4. Types of Blanching
Water Blanching
best for home freezing
Steam Blanching
best for broccoli, sweet potatoes, winter
squash

5. Cont…..
Different Blanching Methods:
1. Pipe blancher
2. Fluidised bed blanching
4. Individual quick blanching
5. Vacuum steam blanching
6. In-can blanching
7. Microwave blanching
8. Hot gas blanching

6. Blanching Equipment's
Water
Blanching
Automatic
Blancher
Manually
Steam
Blanching
Automatic
Blancher
Manually

7. Hot water Automatic Blancher

8. Hot Water blanching
(Ingredient's)
Vegetables Water Salt Ice

9. Hot Water blanching
(Equipment’s)
Large bowl
Slotted
spoon
Large pot Cutting board
and knife
Plate lined with a
cloth or paper
towel

10. Procedure
(Hot water Blanching)
 Bring a large pot of water to boil over high heat.
 prepare the vegetables & cut into Uniform Pieces.
 Add two tablespoons of salt to the boiling water.
 Add the vegetables to the pot in small batches.
 After about 30 seconds, test for doneness. Remove one piece, dip it into the bowl of ice water, and
taste.
 Remove them from the boiling water with a slotted spoon and plunge them into the ice bath to stop the
cooking process.
 When the vegetables are completely cool, remove them from the ice bath and drain on the towel-lined
plate.

11. Automatic steam Blancher

12. Steam Blancher

13. Blancher Cooler

14. Steam Blanching
Choose a sauce pan that comfortably fits your steaming basket
with the lid on.
Place an inch or two of water in the bottom of the pan and bring
to a full boil.
Add the steamer basket containing your prepared vegetables or fruit
and cover the pan tightly with the lid.
Carefully time your blanching per recipe so as not to over-cook your produce. As
a rule of thumb, this will be about half of the cooking time as you would
normally use to fully cook the vegetables.
As soon as the food has been steamed for the recommended time,
immediately remove it from the heat, and run cool water over it to stop
it from cooking any further.

15. Steam Blanching in Microwave

16. Steam Blanching in Microwave

17. Blanching timing Chart

18. Effect on Food
 Nutrients
- Some Nutrition Losses Depends on
- Maturity
- Cutting, Slicing
- Surface are
- Time & Temperature
 Color and Flavor
 Texture

19. Loss ascorbic acid in listed
vegetable
29.1
25 24.2
14
38.7
30.6
22.2
9
15.1
19.5
17.5 18.6
0
5
10
15
20
25
30
35
40
45
Water Blanch-water cool Water Blanch-air cool Steam blanch-water cool Steam blanch-air cool
Loss % of ascorbic acid
Peas Broccoli Green beans

20. Advantage & Disadvantage
Advantage Disadvantage
Stop Enzyme reaction of blanched food
Maintains nutritional value Nutrition is likely to be lost
Maintains Color and flavor Chance to Discolor food due to over heating
Control microbes Some microorganisms remain
Increase Shelf life of food
Cheap Cost

21. C O N C L U S I O N

22. THANK YOU