The document discusses the freeze evaporation dehydration process used for preserving materials and enhancing transportation efficiency, which involves four stages: pretreatment, freezing, primary drying, and secondary drying. It highlights the advantages and applications of this technique across various industries, including food processing, pharmaceuticals, and ceramics, while also addressing its limitations such as high costs and potential structural damage. The process is characterized by the sublimation of water and the controlled use of vacuum to optimize drying.

1. dehydration process which is use to
preserve a material or make the material
more convenient to transport

2. •A slow batch process
•Main 2 techniques
freeze
evaporation
•Use a vacuum system
•Main 4 stages

4. 1. Pretreatment
2. Freezing
3. Primary drying
4. Secondary drying

5. Any method of treating the product before
freezing

6. •Concentrating the product.
•Addition of components to,
- improve stability
- improve processing

7. • Freeze concentration
• Solution phase concentration
• Formulation to preserve product
appearance
• Formulation to stabilize reactive
products
• Formulation to increase surface area
• Decreasing high vapor pressure solvents

8. Can be done in 2 ways;
1. Small scale(in a lab),
-place the material in a freeze drying flask
- rotate the flask in a bath (shell freezer)

9. Cooled by mechanical refrigeration
use,
- dry ice
- methanol
- liquid nitrogen

10. 2.Large scale
-use freeze drying machine

11. * It is important to cool the material below
triple point in both ways

12. •Pressure is lowered
•Enough heat is supplied to the material
(water to sublime)
•95% of water in the material is sublimated
•Process is slow
(much heat could alter the materials structure)
•Pressure is controlled through a application of
partial vacuum.
(speeds up the sublimation)

13. Aim;
-to remove unfrozen water molecules
•Temperature is increased greater than in
primary drying stage

14. •Vacuum is break with an inert gas (Nitrogen)
before material is sealed

15.  Less damages to their physical structures
 No need to refrigerate
 No need to use chemicals for preservation
 Easy to transport
 Can reconstitute quickly and easily
 Can increase the shelf life
 No risk of contamination

16.  Expensive
 Long process time
 Can cause structural deformation
 Storage problems
 Effective for selected items

17. Industry Applications
1.Ceramics To create formable powder
2.Food processing For instant meals and soups.
For breakfast cereals, juices.
For flavorings.
3.Dairy industry High value proteins
4.Nutraceuticals Aloe vera, mussels, shark cartilage.
5.phamaceuticals Protiens,enzymes, hormones,
vaccines and other biological
products.
6.Research Stabilization and storage of
biological materials.
7.Document recovery Water logged artifacts.
Water damaged books and
documents.

18. Industry Applications
8.Starters and cultures For use in cheeses, yoghurts,
meats and probiotics
9.Floral Preserved petals and whole
flowers.
Preserving wedding bouquets and
memorial flowers.
10.Taxidermy Animal preservation.
11.Technological industry Chemical synthesized products.
Late stage purification procedure.

19.  To make ceramic powder
 To produce porous ceramics
 To make ceramic plates
 To create superconductors

20. A water based
ceramic slurry
Freeze while the
growth direction
of ice is
controlled
Sublimation of
ice
Green bodyPorous ceramic

21.  From a sprayed slurry mist.
 Creates softer particles with a more
homogeneous chemical composition.
 More expensive

22.  S/08/924-A.M.P.L. Adikari
 S/08/927- I.N.K. Darandakumbura

23. Thank you!