Preservation by concentration and dehydration

1. OBT554
Unit 3
Dr K.Geetha
Associate Professor, Dept of
Biotechnology, Kamaraj College of Engg
& Tech, Madurai

2. Preservation by Concentration

3. Importance of Concentration

4. Methods of concentration
 Solar concentration - Uses solar energy, Used to derive salt from seawater in
earlier times
 Open Kettles - Heated by steam, Being used for some jellies and jams for
certain types of soups
 Flash Evaporators - Subdivides food material and brings it into direct contact
with the heating medium to speed up concentration process. Superheated
steam at 150°C is used
 Thin film evaporator
 Vacuum evaporator
 Freeze concentration
 Ultra filtration & reverse osmosis

5. Solar concentration

6. Open Kettles

7. Flash Evaporators

8. Thin film evaporator

9. Vacuum evaporator

10. Freeze concentration

11. Ultra filtrationReverse osmosis

12. Examples of Concentrating Foods

14. More common concentrated foods include
evaporated and sweetened condensed
 Milks
 Fruits and vegetable juices
 Nectars
 Sugar syrups and flavored syrups
 Jams and jellies
 Tomato paste and
 many type of fruit purees made by bakers, candy
makers etc.

15. Preservation by Dehydration

17. Importance of Dehydration

18. Methods of Dehydrating Food

27. Fruit Juice Powder

34. Difference between Concentration & Dehydration

35. THANK YOU