Lyophilization is the process of preserving food by removing its moisture through sublimation, i.e. evaporation of water molecules. The lyophilization process will cause a drastic change in the texture of the food when compared to other food preservation processes such as canning or freezing. But on the other hand, lyophilization is the best way to maintain the nutritional content and taste of the food as a whole. Food that has been preserved through this process will be very light in weight, so it is perfect for you to take with you on long trips or you can also use it as a backup food for emergency situations. Read this article to learn more about how to lyophilize food.
Step
Method 1 of 5: Preparation Before Lyophilization
Step 1. Select the type of food you want to preserve
Foods that contain a lot of water are very suitable for preservation by lyophilization. The structure and texture of the fruit will remain intact after going through this process. Here are some examples of foods that are suitable for preservation by this process:
- Fruits such as apples, bananas, various types of berries, persimmons, and pears.
- Vegetables such as potatoes, peppers, carrots, and sweet potatoes.
- If you're used to lyophilization, you can try preserving chicken breasts, cheese, or even processed foods, such as spaghetti or meatballs. All moist food can be preserved through this process.
Step 2. Choose the freshest foods
Foods that are preserved at the peak of ripeness or freshness will have a more consistent taste when consumed after reprocessing.
- Fruits and vegetables should be lyophilized in season when they are at their peak of ripeness.
- Meat should also be processed right after the meat is cooked and cooled.
- Processed foods, such as spaghetti or meatballs, for example, should be lyophilized as soon as possible after cooking and cooling. If you process it a few days after you store it in the refrigerator, then the food will not taste fresh and will not taste good when it is reprocessed for consumption.
Step 3. Don't preserve food that won't taste good after reprocessing
Berries and apples do not need to be reprocessed for consumption because their taste and texture retains well even though they have gone through the lyophilization process. Do this preservation process on meat or spaghetti, which needs to be reprocessed so that it is moist again and can be consumed later.
- Bread is an example of a food that is not suitable to be preserved in this way, as its texture is highly dependent on its freshness.
- Cakes, biscuits, and other types of food made with yeast are also not food types suitable for processing in this way.
Step 4. Prepare the food to be preserved
Do some of the processes below before you preserve the food:
- If possible, wash the food thoroughly, then dry it.
- Cut food into small pieces. Cut apples, peppers, potatoes, and other types of fruits and vegetables into small pieces, so that moisture is easily removed.
Method 2 of 5: Lyophilization Process with Freezer
Step 1. Place the food on a plate or tray
Spread the food evenly so it doesn't pile up.
Step 2. Place the tray in the freezer
If possible, leave only the food you want to preserve in the freezer, with no other items.
- Do not open the freezer frequently. Frequently opening the freezer while food is being processed will slow down the process and will also cause ice crystals to form on the food.
- Use a deep freezer if you have one. Foods that are preserved through the lyophilization process should be kept at the lowest possible temperature.
Step 3. Leave the food in the freezer until the lyophilization process is complete
After a week or so, the sublimation process on the food will be completed, and the moisture in the food will disappear.
To ensure that you have been successful in preserving it, you can take small pieces of the food and let it thaw. If the food looks black, then the food has not finished undergoing the lyophilization process
Step 4. Save the food
When food has finished going through the lyophilization process, you can store it in a special freezer bag. Remove the air content from the bag, seal the bag tightly, then store food in the freezer, pantry, or in your emergency food storage box.
Method 3 of 5: Lyophilization Process with Dry Ice
Step 1. Store food in special freezer bags
Flatten the food in the bag so it doesn't pile up on one side.
- Remove the air from the bag, then close it tightly.
- Make sure that the bag is tightly closed and airtight.
Step 2. Store the bag in the cooler
Place dry ice on all sides of the bag.
- Always wear gloves and long sleeves when you use dry ice.
- If you have a lot of food bags you want to store, you can alternate between bags and dry ice until the cooler is full.
Step 3. Store the cooler in the freezer
After 6 hours, close the cooler. After 24 hours, check whether dry ice is still remaining or not. If there is no dry ice left, the food is ready to be stored.
Step 4. Remove the food bag from the cooler
Store the bags in the freezer, food storage cupboard, or in your emergency food storage box.
Method 4 of 5: Lyophilization by Vacuum Chamber
Step 1. Place the food on a plate or tray
Spread the food evenly so it doesn't pile up.
Step 2. Place the tray in the freezer
If possible, leave only the food you want to preserve in the freezer, with no other items.
- Do not open the freezer frequently. Frequently opening the freezer while food is being processed will slow down the process and will also cause ice crystals to form on the food.
- Use a deep freezer if you have one. Foods that are preserved through the lyophilization process should be kept at the lowest possible temperature.
Step 3. Place the frozen food into a vacuum chamber with a setting of 120 m Torr and a temperature of 10 degrees Celsius
- The sublimation process should be completed within a week, depending on the settings you use in the vacuum chamber.
- After a week has passed, inspect any of the preserved pieces to make sure that the curing process is complete.
Step 4. Store food in airtight containers
Method 5 of 5: Reprocessing Lyophilized Food
Step 1. Remove food from its storage container
Place in a pot or bowl.
Step 2. Bring enough water to a boil
When the water is boiling, turn off the stove.
Step 3. Pour a small amount of boiling water over the previously lyophilized food
The hot water will be absorbed by the food so that the food will be moist again. If the water looks not enough, then pour a little more. Repeat this step until the food looks back to its natural texture.
Tips
The purpose of lyophilizing food is to reduce water and moisture content, so that microbial activity in food is inhibited. A silica gel bag can help in reducing the possibility of condensation and moisture in the container
Warning
- Be careful when using dry ice. In direct contact, dry ice will burn your skin.
- Make sure you store food properly so it doesn't rot.
The Things You Need
- Food to be preserved
- Metal tray
- Freezer (freezer)
- Special lyophilization vacuum chamber
- Glass jars or resealable bags
- Label.
