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ASTROVE

Field guide 01 / Process

What is freeze-dried fruit?

The short answer

Freeze-dried fruit is real fruit that has been frozen and then dried under reduced pressure, so its ice turns straight into vapour instead of melting. This is called sublimation. Because the water leaves without first becoming liquid, the fruit keeps much of its shape, and what remains is dry, light, porous and usually crisp.

Also called
Lyophilisation
How water leaves
As vapour, directly from ice
Typical result
Dry, light, porous, usually crisp
Added by the process
Nothing

Updated Sources

Freezing comes first, and it shapes what follows

Before any water is removed, the fruit is frozen solid. Most of its water becomes ice; a small share stays bound to the fruit’s solids and is dealt with at the very end.

That ice turns the fruit into a rigid, stable matrix for drying. The size of each ice crystal also largely sets the size of the pore it will leave behind.

Slower freezing
Larger ice crystals, larger pores and faster drying later. Crystals that grow too large can damage the fruit’s cells.
Faster freezing
Smaller ice crystals and finer pores.

So freezing is a quality decision, not a warm-up. Freezing conditions have been shown to affect the colour, volume and aroma of freeze-dried fruit, as well as how long it takes to dry.

Sources Yao et al., 2023Uwineza & Zhang, 2026Bhatta et al., 2020

Sublimation: ice becomes vapour without melting

Ice normally melts into water before it evaporates. Lower the pressure far enough and that middle step disappears.

Below the triple point of water, the one combination of temperature and pressure at which ice, liquid water and vapour can coexist, ice cannot become liquid. Given a little heat, it turns directly into vapour instead. That change is sublimation, and it is the core of freeze-drying.

The process, in four stages

  1. Freeze

    Water to ice

    The fruit is frozen solid.

  2. Lower the pressure

    Below the triple point

    The frozen fruit sits in a sealed chamber while a vacuum is drawn.

  3. Primary drying

    Ice to vapour

    Gentle, controlled heat drives sublimation. The vapour condenses on a very cold surface, which keeps the vacuum working.

  4. Secondary drying

    Bound water to vapour

    Water still bound to the fruit’s solids is removed by desorption, at a somewhat higher but still controlled temperature.

Throughout, the fruit has to stay below its collapse temperature. Above it, the drying structure softens and loses its pores. Staying under that limit is a large part of why freeze-drying is slow, energy-intensive and comparatively expensive.

Sources Bhatta et al., 2020Uwineza & Zhang, 2026

Why freeze-dried fruit is crisp

Where the ice was, a space remains.

Schematic: ice crystals become pores A simplified drawing, not a micrograph. Left, frozen: an ice crystal sits inside each cell of a stylised fruit tissue. Right, after sublimation: the cell walls remain in place and each space the ice occupied is empty.
Simplified schematic, not to scale and not a micrograph. It shows the general principle: after sublimation the solids stay largely in place and the spaces the ice filled become pores.

Sublimation happens while the fruit is still frozen and rigid, so its solids stay largely where they were. What is left is an open, porous network holding very little water. Reviews describe that dry network as brittle, which is what you experience as crispness.

Conventional drying tends to go differently. Shrinkage and collapse are common when fruit is dried with warm air, which is why conventionally dried fruit is often denser and chewier. Freeze-dried vs dehydrated fruit sets the two methods side by side.

Crisp is typical, not guaranteed. Texture depends on the fruit, any pretreatment and the drying conditions: published work includes freeze-dried strawberries that came out neither crunchy nor crispy until they were pretreated.

The same open structure takes up water easily. Left open to humid air, freeze-dried fruit absorbs moisture and gradually loses its crunch, which is why it is packed dry and sealed.

Sources Uwineza & Zhang, 2026Bhatta et al., 2020

What freeze-drying changes, and what it does not

Water
Most of it is removed: frozen water by sublimation, then much of the remaining bound water by desorption. How much stays in a finished product is that product’s specification, not a universal number.
Shape
Often largely kept. Freeze-dried fruit typically shrinks less than hot-air-dried fruit, although results depend on the fruit and the process.
Flavour
With most of the water gone, the fruit’s flavour is carried in far less weight, so it tends to taste more concentrated. Reviews report that freeze-drying generally preserves colour and flavour well.
Nutrients
Retention varies. Where freeze-drying has been compared directly with hot-air drying, it has often retained more of several heat-sensitive compounds. How much depends on the fruit, the nutrient, pretreatment, freezing and drying conditions, and storage.
Sugar
Naturally occurring sugars stay in the fruit. Removing water concentrates them by weight along with everything else, so portion size still matters.
Additions
None from the process itself. Freeze-drying removes water; it does not add sugar, syrup or preservatives. Whether a product contains anything besides fruit is on its ingredient list.

No single nutrient-retention percentage holds across fruits and processes, so this guide does not give one.

Sources Uwineza & Zhang, 2026Nemzer et al., 2018Yao et al., 2023

Freeze-dried fruit, as ASTROVE makes it

ASTROVE freezes real fruit first, then removes its water under vacuum rather than relying on prolonged hot-air drying.

These facts describe ASTROVE’s current range. They are not general properties of freeze-dried fruit.

Ingredient
One fruit per pouch: Alphonso Mango, Jamun or Pineapple
Pouch
20g
Sugar
No added sugar. Contains naturally occurring sugars.
Preservatives
No added preservatives
Fresh fruit
Approximately 200–225g of fresh fruit goes into one 20g pouch. Freeze-drying removes most of the water, leaving 20g of freeze-dried fruit. Exact input varies by fruit, season and batch.
Moisture
4.0% max. Manufacturer product specification for all three ASTROVE SKUs, not a single-batch test result.
Shelf life
24 months
Storage
Keep ASTROVE sealed in a cool, dry place away from direct sunlight. After opening, reseal the pouch tightly.

Source / ASTROVE product specification and nutrition information

Three fruits, freeze-dried

Same process, three different results. Mango, Jamun and Pineapple hold different amounts of water and come out of the process with different textures.

Keep reading

Sources

General statements about freeze-drying on this page come from the peer-reviewed work below. ASTROVE product facts come from ASTROVE’s own product specification and nutrition information.

  1. Bhatta S, Stevanovic Janezic T, Ratti C (2020). Freeze-Drying of Plant-Based Foods. Foods, 9(1), 87. doi:10.3390/foods9010087
  2. Uwineza A, Zhang X (2026). Application of Freeze-Drying Technology in the Food Industry: A Review. Foods, 15(4), 790. doi:10.3390/foods15040790
  3. Yao J, Chen W, Fan K (2023). Novel Efficient Physical Technologies for Enhancing Freeze Drying of Fruits and Vegetables: A Review. Foods, 12(23), 4321. doi:10.3390/foods12234321
  4. Nemzer B, Vargas L, Xia X, Sintara M, Feng H (2018). Phytochemical and physical properties of blueberries, tart cherries, strawberries, and cranberries as affected by different drying methods. Food Chemistry, 262, 242–250. doi:10.1016/j.foodchem.2018.04.047