Food Preservation Techniques

Preservatives Added

Canning

Freezing

Dehydration

Irradiation

Freeze-Drying

Packaging

Fermentation

Dehydration

• Helps to ensure microbes don’t live

• Decreases enzyme activity

• Decrease weight of food

Principles

• Add heat to remove water

• This could be through sun-drying

• Or by using special dehydrators

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

Controlling Dehydration

• Air must be able to circulate

• Temperature must be monitored

• Must avoid bacteria and spoilage

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