1. Food Preservation Techniques
Packaging
Canning
Preservatives Added
Fermentation
Food Preservation Techniques
Irradiation
Freezing
Dehydration
Freeze-Drying

2. Dehydration Helps to ensure microbes don’t live
Decreases enzyme activity
Decrease weight of food

3. Principles Add heat to remove water This could be through sun-drying
Or by using special dehydrators

4. Dehydration Regardless, you need to control it!
Still need some water content (15-20% of original moisture content)
Otherwise flavour and nutritional content is decreased

5. Controlling Dehydration
Air must be able to circulate
Temperature must be monitored
Must avoid bacteria and spoilage

6. Controlling & Pre-treatment…
Define the following terms:
Case-Harden
Sulfiting
Sulfuring
Blanching (both steam & syrup blanching)
Sun Drying
Room Drying
Oven Drying
Dehydrators
Dehydro-Freezing

7. Case-Harden
the hardening and darkening of the surface of certain foods caused by too rapid evaporation during dehydration

8. Sulfiting
Adding certain substances such as sodium sulfite to foods as a preservative to prevent spoilage by microorganisms.

9. Sulphuring
Exposing food to burning sulphur or gaseous sulphur dioxide is a pre-treatment for dried fruit which improves its appearance.

10. Blanching (both steam & syrup blanching)
Blanching is dipping fruit or vegetables in boiling water before drying which results in softened texture.
Syrup blanching is dipping fruit or vegetables in boiling sugar syrup before drying which results in softened texture. Results in a sweet taste and more calories.

11. Sun Drying
The practice of drying fruits outside in the sun. The fruit must be taken in at night or the cooler air will reverse all the daytime drying.

12. Room Drying
Process of drying fruits, vegetables, herbs indoors at room temperature.

13. Oven Drying
Using an oven at about 190 degrees F. to dry fruits or vegetables.

14. Dehydrators
Appliances designed to dry fruits and vegetables with low heat and air circulation.

15. Drying of Meat and Fish
Fish and meat can be dried by air drying.