Food Dehydration Flashcards
What was the first kind of food drying technology?
Sun drying foods.
What is the primary goal of Dehydrating foods?
decrease available moisture to prevent microbial growth and chemical reactions
What are the three common drying methods of dehydration?
Heat alone
Spray drying
Freeze drying
What are the requirements and conditions for dehydration?
heat
What is Cause hardening? when dose it happen?
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.
Will the use of smaller pieces for drying reduce the effects of case hardening?
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.
What is the principle of Spray drying?
Fluid foods are sprayed into a stream of hot air.
What is the principle of Fluidised bed drying?
Beds of particulate food are lifted by hot air.
What is the principle of Fluidised bed drying?
Beds of particulate food are lifted by hot air.
What is the scientific principle of dehydration?
Water changes phase at 0C and 100C at normal atmospheric pressure.
True or false:
Water has a low vapour pressure.
False
It has a high Vapor pressure.
Under high pressures, will water boil at a higher or lower temperatures?
Water will begin to boil at higher temperatures.
Under low pressures, will water boil at higher or lower temperatures?
Lower temperatures.
Under low pressures, will water boil at higher or lower temperatures?
Lower temperatures.
What is the main principle driving Vacuum drying?
Water changes phase from liquid to gaseous at a lower temperature due to being in a extremely low pressure environment.
What is freeze drying?
A frozen food is placed into a vacuum chamber, where the water then Sublimes from the frozen food.
Goes from Solid to Vapour
What dose it mean when a substance “Sublimes”
Goes from solid to vapourous without going into a liquid phase.
What dose it mean when a substance “Sublimes”
Goes from solid to vapourous without going into a liquid phase.
What are three examples of freeze dried foods?
- Toddler food products
- Dog food (reconstitutes)
- Thrive freeze dried emergency food (shelf-life of 25+ years)
What is the principle of Vacuum Drying?
Water removed by creation of a vacuum
What is the principle of Roller Drum Drying?
Pasty food applied to a heated drum is scraped off after drying
What is the principle of Freeze drying?
Water removed by sublimation from frozen foods under vacuum
What is so interesting about the B.C company Enwave?
The business of microwave preservation of foods.
grossing 2 billion $ a year
What is the principle of Vacuum microwave dehydration?
Dehydrating foods through the use of a microwave.
it is faster and less expensive than freeze drying, also minimizes heat damage to the food.
What is the focus of Enwave?
The sales of equipment to food and drug manufactures
Is solar processing viable?
It is, although due to the lack of general understanding and research it has been under used within warmer locations.
What are some examples of Solar Drying mechanisms?
Solar dryers
Concentrators
Ovens
What are some of the products that can be made through solar-powered food processing?
Roasted peanuts
jams
Pasteurized fruit jams
Whats the diffrence between processing and preservation
Preservation = extention of shelf life
Processing = transformation of product (often with the goal of processing)
What are the three trade offs of preservation and processing?
- shelf life extension
- Food quality/nutrition
- Safety
How can we increase the rate of food drying?
By making the products small, with a large surface area.
Need air movement.
Increasing the temperature or pressure.
Vacuum drying prevents what?
Case hardening
and limits the loss of flavor.
(at the off set of increasing in cost)
What is the ultimate advantage of Freeze drying?
Value added
Light weight
Longer shelf life.
