Food Dehydration

Question 1

What was the first kind of food drying technology?

Answer 1

Sun drying foods.

Question 2

What is the primary goal of Dehydrating foods?

Answer 2

decrease available moisture to prevent microbial growth and chemical reactions

Question 3

What are the three common drying methods of dehydration?

Answer 3

Heat alone
Spray drying
Freeze drying

Question 4

What are the requirements and conditions for dehydration?

Answer 4

heat

Question 5

What is Cause hardening? when dose it happen?

Answer 5

The products exterior drys and creates a barrier that prevents the moisture from leaving the inner portion of the product.

Shortens the shelf life of the product.

Question 6

Will the use of smaller pieces for drying reduce the effects of case hardening?

Answer 6

It will, as it allows the enhancement of moisture loss of the product.

The greater the surface area, the greater the amount of water loss available.

Question 7

What is the principle of Spray drying?

Answer 7

Fluid foods are sprayed into a stream of hot air.

Question 8

What is the principle of Fluidised bed drying?

Answer 8

Beds of particulate food are lifted by hot air.

Question 9

What is the principle of Fluidised bed drying?

Answer 9

Beds of particulate food are lifted by hot air.

Question 10

What is the scientific principle of dehydration?

Answer 10

Water changes phase at 0C and 100C at normal atmospheric pressure.

Question 11

True or false:

Water has a low vapour pressure.

Answer 11

False

It has a high Vapor pressure.

Question 12

Under high pressures, will water boil at a higher or lower temperatures?

Answer 12

Water will begin to boil at higher temperatures.

Question 13

Under low pressures, will water boil at higher or lower temperatures?

Answer 13

Lower temperatures.

Question 14

Under low pressures, will water boil at higher or lower temperatures?

Answer 14

Lower temperatures.

Question 15

What is the main principle driving Vacuum drying?

Answer 15

Water changes phase from liquid to gaseous at a lower temperature due to being in a extremely low pressure environment.

Question 16

What is freeze drying?

Answer 16

A frozen food is placed into a vacuum chamber, where the water then Sublimes from the frozen food.

Goes from Solid to Vapour

Question 17

What dose it mean when a substance “Sublimes”

Answer 17

Goes from solid to vapourous without going into a liquid phase.

Question 18

What dose it mean when a substance “Sublimes”

Answer 18

Goes from solid to vapourous without going into a liquid phase.

Question 19

What are three examples of freeze dried foods?

Answer 19

• Toddler food products
• Dog food (reconstitutes)
• Thrive freeze dried emergency food (shelf-life of 25+ years)

Question 20

What is the principle of Vacuum Drying?

Answer 20

Water removed by creation of a vacuum

Question 21

What is the principle of Roller Drum Drying?

Answer 21

Pasty food applied to a heated drum is scraped off after drying

Question 22

What is the principle of Freeze drying?

Answer 22

Water removed by sublimation from frozen foods under vacuum

Question 23

What is so interesting about the B.C company Enwave?

Answer 23

The business of microwave preservation of foods.

grossing 2 billion $ a year

Question 24

What is the principle of Vacuum microwave dehydration?

Answer 24

Dehydrating foods through the use of a microwave.

it is faster and less expensive than freeze drying, also minimizes heat damage to the food.

Question 25

What is the focus of Enwave?

Answer 25

The sales of equipment to food and drug manufactures

Question 26

Is solar processing viable?

Answer 26

It is, although due to the lack of general understanding and research it has been under used within warmer locations.

Question 27

What are some examples of Solar Drying mechanisms?

Answer 27

Solar dryers
Concentrators
Ovens

Question 28

What are some of the products that can be made through solar-powered food processing?

Answer 28

Roasted peanuts
jams
Pasteurized fruit jams

Question 29

Whats the diffrence between processing and preservation

Answer 29

Preservation = extention of shelf life

Processing = transformation of product (often with the goal of processing)

Question 30

What are the three trade offs of preservation and processing?

Answer 30

1. shelf life extension
2. Food quality/nutrition
3. Safety

Question 31

How can we increase the rate of food drying?

Answer 31

By making the products small, with a large surface area.

Need air movement.

Increasing the temperature or pressure.

Question 32

Vacuum drying prevents what?

Answer 32

Case hardening
and limits the loss of flavor.

(at the off set of increasing in cost)

Question 33

What is the ultimate advantage of Freeze drying?

Answer 33

Value added
Light weight
Longer shelf life.