Does Freeze Drying Remove Nutrients?

Freeze drying removes water from food, but does freeze drying remove the nutrients along with it?

The short answer is no.

Freeze drying removes moisture, not nutrition as a whole. It can preserve nearly all of the nutritional value of many foods while also making it possible to store that food for years.

That's one of the biggest advantages of freeze drying. It removes most of the water without relying on prolonged high-temperature processing. Once food is completely freeze dried, appropriate packaging helps protect it from moisture, oxygen, and light during storage.

When completely freeze dried, appropriately packaged, and stored under suitable conditions, many foods can last for years, and some can last up to 25 years.

No preservation method keeps every nutrient completely unchanged forever, and different nutrients respond differently to processing and storage. But freeze drying offers an impressive combination of nutrient retention, food quality, and long-term shelf life.

Why Does Freeze Drying Preserve Nutrients So Well?

Several things that affect food over time can also affect its nutritional quality, including moisture, heat, oxygen, light, and time.

Freeze drying addresses several of these factors.

First, food is frozen. Then, under vacuum, most of the frozen water is removed as vapor through a process called sublimation.

Because freeze drying removes moisture at relatively low product temperatures compared with many conventional drying methods, food isn't subjected to the prolonged higher temperatures used in some other preservation processes.

That can be especially helpful for nutrients that are sensitive to heat.

Removing the water is important too.

How Does Removing Water Preserve Food?

Moisture plays a major role in food spoilage. Bacteria, mold, and yeast need available moisture to grow, and water also contributes to chemical and enzymatic reactions that can affect food quality over time.

Freeze drying removes most of that moisture, helping slow microbial growth and many of the changes that cause food to deteriorate.

Once the food has been freeze dried, packaging becomes an important part of protecting it.

For long-term storage, freeze-dried food is commonly stored in Mylar bags or other airtight containers with oxygen absorbers. This helps protect the food from moisture and oxygen. Storage temperature, exposure to light, packaging quality, storage time, and the type and condition of the food can all affect how well it maintains its quality over time.

Together, the freeze-drying process and appropriate storage help protect food from several of the conditions that cause it to deteriorate.

The Nutritional Starting Point Matters

The nutritional content of food isn't necessarily fixed from the moment it's harvested until the moment it's eaten.

Time, temperature, transportation, handling, and storage can affect certain nutrients in fruits and vegetables.

That means the condition of the food when preservation begins matters. Produce freeze dried shortly after purchase or harvest may have a different nutritional starting point than produce that has spent additional time in storage.

Freeze drying can only preserve the nutrients that are present when preservation begins.

That's one reason starting with fresh, good-quality food is important.

How Much Nutrition Does Freeze Drying Preserve?

Freeze drying can preserve nearly all of the nutritional value of many foods, although the exact amount varies depending on the food and the nutrients being measured.

Different nutrients respond differently to processing. Some vitamins are more sensitive to heat, oxygen, and storage conditions, while protein, fiber, minerals, and other nutrients are generally more stable.

Because freeze drying removes water at relatively low product temperatures, it can retain many nutrients very well while preserving the food for long-term storage.

Rather than focusing on one percentage for every food, the important takeaway is that freeze drying is highly effective at preserving both food and much of its original nutritional value.

What Nutrients Remain After Freeze Drying?

Food contains many different nutrients and compounds, and they don't all respond to processing in exactly the same way.

Freeze-dried foods can retain:

• Protein

• Carbohydrates

• Fats

• Fiber

• Minerals

• Many vitamins

• Carotenoids

• Phenolic compounds and other naturally occurring compounds

Some nutrients are more stable than others.

Vitamin C, for example, is relatively sensitive to heat, oxygen, and storage conditions. Research comparing drying methods has found that freeze drying can perform well for retention of certain vitamins and other food qualities, particularly compared with conventional higher-temperature drying.

Minerals such as calcium, iron, magnesium, potassium, and zinc behave differently. They aren't destroyed by heat in the same way that some vitamins can degrade.

Protein also remains in freeze-dried food. A piece of freeze-dried meat doesn't lose its protein simply because the water has been removed.

The exact amount of any individual nutrient retained will depend on the food, the nutrient, preparation, processing, packaging, and storage.

But the important point is simple:

Freeze drying removes water. It does not remove the nutritional value of the food along with it.

Does Freeze-Dried Food Have More Nutrients?

Sometimes nutrition labels or comparisons can make freeze-dried food appear to contain more nutrients than fresh food.

Usually, that's because the water has been removed.

For example, 100 grams of fresh strawberries and 100 grams of freeze-dried strawberries don't represent the same amount of original fruit.

Fresh strawberries contain a large amount of water. Freeze-dried strawberries contain very little.

So 100 grams of freeze-dried strawberries represents much more original strawberry material. Nutrients can therefore appear more concentrated by weight.

Freeze drying didn't create additional nutrients. It removed water.

Freeze Drying vs. Dehydrating: What About Nutrients?

Both freeze drying and dehydrating remove water, but they do it differently.

Traditional dehydration generally uses heat and airflow to evaporate moisture.

Freeze drying first freezes the food and then removes much of its water under vacuum through sublimation.

Because conventional dehydration often exposes food to higher temperatures, some heat-sensitive nutrients and other food qualities can be affected.

Freeze drying's lower-temperature process is one reason it can be particularly effective at retaining many of the characteristics of the original food, including nutrients, color, flavor, and structure.

That doesn't make dehydration a poor preservation method. Sometimes the different result is exactly what you want. Jerky and fruit leather are good examples.

But when maintaining qualities closer to the original food is the goal, freeze drying has important advantages.

What About Freezing?

Freezing can also preserve nutrients well.

But there's an important difference when you're thinking about food preservation over the long term.

Frozen food has to stay frozen. Freeze-dried food does not.

Freeze drying removes most of the water from food, substantially reduces its weight, and allows completely dried and appropriately packaged food to be stored without continuous refrigeration.

When completely freeze dried, appropriately packaged, and stored under suitable conditions, many foods can last for years, with some lasting up to 25 years.

So the nutrition question isn't only about how much of a particular nutrient remains immediately after processing.

It's also about how well the food can be preserved over the length of time you actually want to store it.

That combination of strong nutrient retention and long-term shelf-stable storage is one of the things that makes freeze drying unique.

Does Storage Affect Nutrients in Freeze-Dried Food?

Yes. Freeze drying is only part of successful long-term food preservation.

After processing, exposure to moisture, oxygen, light, and higher storage temperatures can continue to affect food quality and certain nutrients over time.

That's why appropriate packaging and storage are so important.

Completely dried food should be protected from moisture and oxygen. Mylar bags or other airtight containers with oxygen absorbers are commonly used for long-term storage, and keeping food in a cool, dry, dark location can help protect its quality.

No preservation method makes every nutrient immune to change forever.

But freeze drying, followed by appropriate packaging and storage, can preserve food and much of its nutritional value for a remarkably long time.

The Bottom Line

Freeze drying is one of the best ways to preserve food while maintaining much of its nutritional value.

It removes most of the water without relying on prolonged high-temperature processing. Removing moisture helps slow microbial growth and many of the chemical and enzymatic changes that cause food to deteriorate. Appropriate packaging then helps protect the food from moisture, oxygen, and light during storage.

And unlike food that has to remain refrigerated or frozen, completely freeze-dried and appropriately packaged food can be stored for years, with some foods lasting up to 25 years under suitable conditions.

No preservation method keeps every nutrient unchanged forever, and the exact amount of individual nutrients retained will vary by food, processing, and storage.

But if your goal is to preserve food for later while maintaining much of what made it nutritious in the first place, freeze drying is hard to beat.

Frequently Asked Questions

Does freeze drying destroy vitamins?

Freeze drying can retain many vitamins very well. Some vitamins are more sensitive than others, so the amount retained depends on the food, the vitamin, processing, and storage conditions.

Does freeze drying remove protein?

No. Freeze drying removes water, not the protein in food. Meat, eggs, dairy products, and other protein-containing foods retain protein after freeze drying.

Does freeze drying remove minerals?

Freeze drying does not simply remove minerals from food. Minerals such as calcium, iron, magnesium, potassium, and zinc are generally more stable than many vitamins.

Is freeze-dried food as nutritious as fresh food?

Freeze-dried food can retain much of the nutritional value present when preservation begins. The comparison also depends on the condition of the food at that point, since certain nutrients can change over time during transportation, handling, and storage.

Is freeze-dried food healthier than dehydrated food?

Both can be part of a healthy diet. Freeze drying has an advantage for some heat-sensitive nutrients and other food qualities because it generally uses lower product temperatures than conventional dehydration.

Does freeze-dried food lose nutrients over time?

Some nutrients can change during storage. Protecting freeze-dried food from moisture, oxygen, light, and high temperatures helps maintain its quality and nutritional value over time.

How long can freeze-dried food last?

When food is completely freeze dried, appropriately packaged, and stored under suitable conditions, many foods can last for years, and some can last up to 25 years.