What Is Freeze-Drying?
Freeze-drying is a method of dehydration to keep perishable food items for a long time. It is one of the food preservation techniques that focuses on the sublimation of water content in a food. This method is also known as lyophilization.
Freeze-drying directly converts the water content in a portion of food from a solid to the gaseous state, without converting it into the liquid state. You will find a large variety of freeze-dried food items in any store. From fruits to ready-to-eat meals, all are freeze-dried.
There are a few specific reasons why freeze-drying is regarded as the most effective dehydration process. Check them out in the following points:
- It can be done at low temperatures. This helps to maintain the nutritional content and flavor of a food.
- Freeze-drying is suitable for food products with high-sensitive ingredients, that would otherwise get ruined in other food preservation techniques.
- It stops the microbial and chemical reactions thus extending the shelf life of the dehydrated food items.
How Does Freeze-Drying Work?
Raw food contains about 85-95% water. In this process, the food is first frozen to remove this moisture. The process freezes the water, which remains frozen all the time. This step is different from vacuum drying, so be careful while doing this at home.
The freeze-drying process can be categorized into the following two points:
- Primary drying is the first step that eliminates a majority of the water content from the food.
- Next comes secondary drying, where the remaining water is dried.
NOTE: Since freeze-drying is a critical method, it should only be used under specific conditions and limitations. This should be done to keep the water from melting.
What To Freeze Dry?
Most freeze-dried items are plant-based foods, but a variety of foods can be preserved with this technique. Check out the following list of foods that you can freeze dry:
- All kinds of fruits
- Vegetables
- Meat
- Dairy-based products
- Plant-based products
- Herbs and spices
- Eggs
- Easy meal prepping
- Sweeteners such as maple syrup
- Instant drinks
Is It A Good Idea To Freeze Dry?
Yes, it is a good idea to freeze dry. This is because freeze-dried foods are healthy meal options that have their nutritional value intact. Additionally, this process also preserves the color, texture, and flavor of the food. And for these benefits, freeze-drying is widely used to create high-quality food products.
This method is also a major part of the pharmaceutical industry as it keeps the products safe for a long time. This is the most effective technique to maintain antioxidants, including ascorbic acid or vitamin C, flavonoids, and anthocyanins.
However, the content of phytochemicals in fruits could at times increase or decrease as a result of freeze-drying. But this will greatly vary according to the type of fruit. Therefore, be careful while you freeze-dry at home.
What Are The Possible Downsides Of Freeze-Drying?
While freeze-drying has a lot of benefits, here are some downsides that you need to be careful of while freeze-drying at home. Check them out below:
- Reducing the water content can possibly reduce microbial growth in food items, but some microbes can still survive the drying process. Therefore, be careful.
- Freeze-dried foods have an increased porosity level, which means they might be accessible to oxygen, thus boosting oxidation.
- Freeze-drying does not completely kill the bacteria, therefore, it is better if you cook the food before consumption to avoid food-borne illness.
Summing it up, that was all about freeze-drying foods and what to freeze dry. Now, you know all the possible outcomes of freeze-drying. So, the next time you are dealing with freeze-dried foods, you know what to do.
