by zalina richelle n.
Skip this Video
Loading SlideShow in 5 Seconds..
By: Zalina & Richelle PowerPoint Presentation
Download Presentation
By: Zalina & Richelle

Loading in 2 Seconds...

play fullscreen
1 / 10

By: Zalina & Richelle - PowerPoint PPT Presentation

  • Uploaded on

Freeze–Drying Foods. By: Zalina & Richelle. What is Freeze-Dried Foods?. Essentially, extracting all the water molecules from a food item Outcome is a product that can be kept in room temperature for a long period of time without spoilage . How Is Freeze Drying Food Done?.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
Download Presentation

PowerPoint Slideshow about 'By: Zalina & Richelle' - amie

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
by zalina richelle

Freeze–Drying Foods

By: Zalina & Richelle

what is freeze dried foods
What is Freeze-Dried Foods?
  • Essentially, extracting all the water molecules from a food item
  • Outcome is a product that can be kept in room temperature for a long period of time without spoilage
how is freeze drying food done
How Is Freeze Drying Food Done?
  • The food item is first cooled below a temperature of zero degrees Celsius
  • Placed into a bag or container which will keep air and moisture from reaching it
  • Then, the container is connected to a vacuum pump
  • The pump will extract the water molecules as they vaporize to establish the vapour pressure
  • All that is left, is the freeze-dried solid
benefits of freeze drying foods
Benefits of Freeze Drying Foods
  • Can keep the original contents of the product: colour, texture, taste, size, and nutrients
  • Returns back into the same state when placed in water
  • Can keep it on a shelf at room temperature – freezer or cold storage not required
  • Mass is reduced, but there is no change in the volume
  • Lack of water reduces/eliminates the chance of bacteria
  • Any type of food or ingredient can be freeze-dried
who uses it
Who Uses It?
  • Hikers/Campers – lighter weight to carry
  • Dieticians
  • Pharmaceuticals – vaccines and injections – sealing material in bottle
  • Astronauts
  • Soldiers
why when it s used
Why/When It’s Used?
  • Emergencies
  • Convenience
  • Long Trips
relation to gas law
Relation to Gas Law
  • Dalton’s Law
      • The total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases.
  • Relation of Dalton’s Law and Freeze-Dried Foods
    • The water molecules establish the vapor pressure as they are vaporized by the vacuum pump from the food item.
    • This causes the foods to have a lower mass.
    • The mass of the food item is equal to sum of the vapor pressure, that is extracted from the food and the freeze-dried solid that is left behind.
history of food in space
History of Food in Space
  • Eating in space for John Glenn turned out to be an easy though not too tasty experience.
  • Some experts were worried that the weightlessness in the food would be hard to swallow and as a result, collect in the throat, but John Glenn had no difficulty.
  • Other Mercury astronauts following John Glenn found the food unappetizing, had trouble rehydrating the freeze-dried foods, and disliked squeezing the tubes.
  • Today freeze-dried foods has become popular among astronauts
  • Canham, Geoffrey. Chemistry 11 . Toronto, Ont.: Addison-Wesley Publishers, 2002. Print.
  • "Freeze-Dry Foods." Freeze-Dry Foods. N.p., n.d. Web. 5 Mar. 2011. <>.
  • "Lyophilization Freeze - Freeze - Dried Food." Inventors. N.p., n.d. Web. 6 Mar. 2011. <>.
  • "What is Freeze Drying?." wiseGEEK: clear answers for common questions. N.p., n.d. Web. 5 Mar. 2011. <>.