Freeze Drying

The none plus ultra in food preservation is freeze drying.

The Andes Mountain Indians were said to have been discovered using the technology.

The function is based on the fact that liquids, including water, will boil at a lower temperature at higher altitudes in comparison to sea level.

The Andes Indians were said to have been seen taking potatoes up the mountain and then leaving them there for 5 weeks. They then brought them back down again and washed them. That might be due to deposits that may have come from the inside or have settled on them, you will have to ask them. They then brought the potatoes back up the mountain for a further week and then the process was finished. From that point on it was clear that drying also depended more on pressure.  As methods became available that could simulate the same mountain conditions at sea level, freeze drying became and industrial process. The industrial use of the process became wide spread in the 1930s. 

The process is now scientifically explained by the name "sublimation". It means that things will move from a solid state to a gas and thereby miss out the liquid phase, if pressure and temperature are correct. 
Example: Most organisms, including people, expel CO2 gas into the air, but it is in liquid form inside the body. That is because internal pressure and temperature are just right.
Once the liquified gasses, including water, have been removed from food, the decaying process will have been brought to that which for all practical purposes can be called a standstill.

At this moment in time no one really knows how long freeze dried goods will remain edible, but it has been stated that with proper storage, Eg. Vacuum pack, freeze dried products can keep up to 25 years or more.

By the way, it is said that the Andes Indians that remain are still using the same method even today.

The possible famine situation in random parts of Africa means that the freeze drying technology is a must for Africa. The documentation says that Africans must assume that they can have up to 7 years of plenty followed by 7 years of famine.

In that context, we want to freeze dry all the good quality leftovers.


   
Build Your OWN Freeze Dryer

1. Knowledge of refrigeration techniques will come in very useful.

2. Get a large size deep freeze and a small size deep freeze. Mount plates with holes that do not overlap in it. That should catch any very tiny particles that get dragged away when the vacuum creation first starts. The other alternative is to design your own version of the second chamber that also includes the connecting pipes and just stretch the same cooling coil from the main deep freeze along it too. Intermediate connections will still need to be accessible from the outside so that washing can be done in both directions.

3. Connect the two together using the correct vacuum components.

4. For fast activity that will reduce 5 weeks wait down to one day, the temperature of the two deep freeze can go down to -40 degree and the vacuum can go down to anywhere between 0.6 and 0.1 bar.

5. Stainless steel is the order of the day when dealing with food, that means that you may have to replace the insides of the deep freezes with stainless steel so that the walls will not cave in due to the low pressure.

6. The next thing that is required is a good vacuum gauge with built in safety valve. It is followed by the vacuum pump. Electric power will be supplied by the SHE.

7. As far as making powdered milk is concerned, you just go strait from the cow, through the milking machine to the freeze dryer with no stops in between.

8. For the time being you can also include heating around the main chamber so that metal trays that will be the containers can be made to expand and reduce sticking. The capability of the insulating materials used will define upper temperatures, but you may also not want oils to evaporate into the vacuum pump and clog it. Remember that generating constant heat inside an insulated area will mean that the temperature inside that area will just keep on rising, if the heat source is not turned off before it gets too hot. Example: Microwave heating.

9. The larger the surface areas that is presented to the vacuum, the better and faster the process. That means that when dealing with something like swollen roots, one can design something that looks like that which is used in beehives as a carrier for the previously cooked and crushed product so that the area presented to the vacuum will be twice as much as a strait forward tray carrier.

10. The industrial process description is as close to an exact replica of the original, whereby:
A. Total deep freeze (eg. Milk freeze capability dependent).

B. Vacuum creation 4/6 of the time.

C. Temperature Increase 1/6 of the time. Keep the vacuum. When dealing with something whereby you want the final product to be a powder, you may want to first take out the content and grind or crush them in order to increase the surface area. 

D. Deep Freeze again. 1/6 of the time. Keep the vacuum.

E. Finished. Now grind to a powder.

F. Note also that when applying the vacuum to tiny particles, the speed of that application should be controlled so that particles do not get dragged out along with the preliminary amount of air. The second chamber in the freeze dryer is required, if such particle movement is to be expected.

11. The SHE can generate heat, therefore if you have a large amount of milk, it can be pasteurized for a day and thereby remove a significant amount of water while the freeze dryer is working on a previous batch of products.
The choice can be to pasteurize one batch of milk in order to deactivate it and remove some aroma. That which is not sold fresh or used for other milk products can then be converted to milk powder.

12. As far as cow's milk and all it's exit products are concerned, no one is interested in flavor or smell, because they are added later, if and when required.

13. If you are freeze drying something like yam, pressure cooking it first in a SHE driven pasteurizer will leave a soup or sauce that contains a certain amount of flavor. If you want, you can use that liquid as a flavor based liquid for a milder vinegar that will later be part of a sauce. Oil is a good aroma store.

Note that cooking is not a prerequisite for freeze drying. 

14. You will need to check how much aroma is left after things like spices have been freeze dried.

15. That said, it can be seen that after you know the sequence, a certain amount of automation could be useful. This is not an advertising platform for a specific automation technology, but in the interest of expediency, a complete computer system that you can get for less than the price of a calf, plus one or two electronic experimental kits with simulator software may save you time rather than have yourself standing around observing a stopwatch too much of the time. You get the professional  components after you know how it works and what you need. Prerequisite is that your internet connection, your information link with the outside world, also has African prices. 
Example: If one wants to get information about refrigerants, most people will start with the common or most well known version name which is "freon".  In that context, Africans that are interested in electronic control and sensors could start by looking for "Mini PC + Win. Pro" as well as "Adriuno" and "sensors & attachments". That should give you a starting point. There are many versions and suppliers, therefore you will have to find the one that suits your needs.
 

               Milk Shake  Types

1. It can be said that there is simply no way to get something down one's throat without water and or fat.
The 3-4% fat content of milk does not seem to weigh heavy against the 50% or more amounts of carbohydrates. It is quite likely that the tongue can detect the presence of a suitable amount of fat and or water.
People that eat a lot of butter, will in many cases, remove the fat from milk, before converting it into something else.

2. Africans will surely like a lot of milk shakes and ice creams, which means that you will not have to worry about having surplus amounts of milk on your hands for 25 years.

3. The picture shows a type of drinking container for milk shakes and ice cream.

4. The outer shell can then contain something like mineral water with may be a touch of something like Baobab fruit juice or something similar that can be used to wash everything down properly, with very little  scrubbing required.

5. Due to the fact that the fat is usually removed from milk during it's conversion to cream, a textural replacement may be called for. With plenty of water, cassava extract may be a good replacement for missing fat and consistency adjustments in very many things. There are other African tubers with similar characteristics, otherwise one may have to revert back to the good old egg. 

6. Converting milk cream to dried milk will require less energy. Try it with your freeze dryer and see why.

7. It is considered good practice to have food that you will sell in distant places tested. In that context, the ion chromatography and the Mass spectrometry seem to produce results that are recognized by certain persons and used for comparisons. For the every day consummation of food, one will probably tend to use taste and feel to make personal decisions, but it will be nice to know, if any atoms or molecules that are too heavy for the human body managed to get past the roots and leaves and on into products, especially if they can not be extracted by freeze drying or other known means. 








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Freeze Drying


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