Fruit Fusion Crunch: Harmonious Blend of Freeze-Dried Fruits

Freeze drying, or lyophilisation, has transformed our capacity to store and preserve everything from food and drugs to flowers and museum artefacts – but how does the freeze dry machine work, and what actually happens in a vacuum to sublimate all that liquid?

The Science Behind Freeze Drying

The first thing you learn about freeze drying is that it’s at the very heart of physics and thermodynamics. It all has to do with such concepts as sublimation and the use of a vacuum.

What is Sublimation in Freeze Drying?

In brief, sublimation is the direct transformation of a solid into a gas, without passing through a state of liquid. How is that possible? The answer is through the use of heat under very low-pressure conditions.

The Key Role of Vacuum in Freeze Drying

That’s where the vacuum comes in. First, it’s important to understand why vacuuming your freezer is a good idea. When low-pressure vacuum conditions are applied, there is less force applied to the atmosphere surrounding the frozen product. Since the surrounds have less pressure than before, the product’s frozen water has no choice but to sublime directly from solid to vapour – since sublimation occurs naturally much faster than liquid evaporation.

The Freeze Drying Process

The freeze-drying process involves three main stages: freezing, primary drying, and secondary drying.

The Freezing Phase

The process of preparation begins with frozen material, so that the preservation of the structure and properties of material in aqueous phase during subsequent drying are ensured.

The Primary Drying Phase

Then the product is cooled to a very low temperature, the material is put in a vacuum and then heated and the water in the material goes to vapor state and it is removed from the system.

The Secondary Drying Phase

Secondly, since the container is under a moderate vacuum, the liquid heated up to a high temperature will start boiling (turn into steam) and, since it can’t escape, it will condense on the surface of the material to form a very thin film. Then, once the product temperature has reached an even higher value, whatever little bit of water molecules can be extracted from the material itself has been taken out of there and the product is bone dry.

The Freeze Dry Machine: A Closer Look

The vat would be placed below, and ride in a raft, underneath a ‘Torrinhaus’ (a kind of vacuum system) to allow access for the warm air to blow through the vat via a strong swift and controlled vortex, and it needn’t be extremely hot, only about the temperature you would have in an oven at home, which is hot enough to blow off the water, leaving the frost on the equipment.After that, the dwelling box, as Hopkins called it, would be an incubating and controlling cooker, a multistorey box with a view. You could literally look inside and see what was happening. There was to be a double-glazing design.

Essential Components

An ordinary freeze drying apparatus contains a drying chamber, a vacuum pump that sucks the vapour to a low-pressure area, and a condenser which condenses the water vapour.

Operations and Maintenance

Using a freeze dryer requires you to configure system temperatures and pressures, you have to periodically test the integrity of the system, and you need to perform regular maintenance.

The Benefits of Freeze Drying

Preservation and Food Storage

This is why the mastery of food preservation techniques such as freeze-drying (which is excellent since it preserves food, and retains most of the nutrient content, colour and texture) is such a bonus for prolonged timespans of food keeping.

Rehydration: Bringing Food Back to Life

A small miracle of dried food is that it really does rehydrate – rehydrate is one of those funny words of food technology, because the food is hardly rehydrated, it has just become something capable of absorbing liquid again. When your moment does arrive, all that you need to do is to add water, and the food will again have absorbed it and gone back to being the meal you remember.

Real-life Applications of Freeze Drying

Freeze Drying in the Food Industry

In industry it is also used to make many kinds of food products like freeze-dried fruits and vegetables and even milk or cheese.

Other Notable Uses of Freeze Drying

Besides foods, it is also used for the preservation of drugs, flowers, and in the manufacturing of instant coffee.

Conclusion

In other words, in very real terms, freeze-drying had become a part of us, from extending the life of food to preserving the application of life-saving drugs.

Frequently Asked Questions

1. How does freeze-drying work?

The process of freeze-drying instead makes use of something called the principle of sublimation: the transformation of a solid directly into a gas, without first going through the liquid state.

2. How does a freeze dry machine work?

A freeze-dry machine is worked under vacuum condition (by heating the material placed inside and then allowing the water suspended in the solids to sublime – and then make the vapour exhaust by blowing air from outside.

3. What does it mean to food and its preservation through Freeze Drying?

foods can be preserved by Freeze Drying: the water in them being removed at a temperature below zero - the advantage being that the food still has the same nutrients, and is still the same colour and texture but shelf-life extended.

4. Then, will you be able to use it?

So, could you [laughs]So, you could use the freeze-dried caviar?Oh, I thought you meant could you eat the freeze-dried caviar.The purée or the what?The purée. you could make… [laughs]Yes! It can be rehydrated! ­– and then you will be able to use it?[interrupting again] You add water. To the purée. Then, then! [laughs] ­– then you’ve got to wait. You can’t just add water and eat it immediately ­– you have to wait.Collazo: Oh, so you have to keep it hydrated.La bouche： Hydrate it?