As one of the most important economic sectors, the food industry plays a key role in providing global food security. Freeze dryer has created a great transformation in this industry by maintaining the quality and increasing the shelf life of products.

What is a freeze dryer?

Freeze dryer or freeze dryer is a device that is used to remove water from different materials (such as food, pharmaceutical and biological). This device uses the freeze drying process to directly convert the water in the material from solid state (ice) to gas state at low temperature. This process helps preserve the texture, flavor, color, and nutrients of the product.

The best way to increase the shelf life of food is the freeze dryer, a device in which the food is first frozen and then turns into steam under very low pressure of the water in the product. This process preserves the taste structure and nutrients of the products and increases its shelf life.

What products can be produced with a freeze dryer machine?

Ice creams

All kinds of ice creams with different flavors are freeze-dried.

Fruits and vegetables

All kinds of fresh fruits such as strawberries, mangoes, apples, bananas and vegetables such as mushrooms, spinach, corn are dried by this machine.

Dairy products and eggs

Dairy products such as milk, cheese and even eggs are produced and stored in powder form in the freeze-drying method.

meat and fish (proteins)

All kinds of cooked or raw meat and fish are well preserved with this method.

Snacks and drinks

All kinds of smoothies and healthy snacks as well as coffee are freeze-dried in powder or liquid form.

Semi-prepared foods

Complete meals such as soups, stews, pasta... are prepared in freeze dryer for long-term use

Spices and herbs

Aromatic herbs such as rosemary and mint are dried in this way to preserve the original flavor.

How the freeze dryer works

۱- Freezing:

• First, the desired materials are frozen in a freeze dryer to a temperature below zero. At this stage, the water in the material turns into ice. This stage is very critical and the quality of freezing has a direct impact on the quality of the final product.

۲- Primary Drying:

• After freezing, the device creates a vacuum so that the air pressure is drastically reduced. In this case, with a slight increase in temperature, the ice turns into a vapor state without passing through the liquid state. This process is called sublimation and the main step is to remove water from the material.
• Sublimation causes water to change from a solid state (ice) to a gas state and leave the material without damaging the material's texture.

Secondary Drying:

• At this stage, the temperature is slightly increased to evaporate the remaining moisture present in the material. This step helps the material reach the lowest possible moisture level and maximize its shelf life.
• Usually, at this stage, the water is molecularly attached to the material and a slightly higher temperature is required to evaporate it.

4- Packaging and storage:

After finishing the drying process, the materials are packed in powder or desired form. The finished product is very light and durable and usually resistant to spoilage.

Advantages of using a freeze dryer

• Retention of quality: Due to the low temperature drying process, nutrients, aroma and taste of the material are preserved.
• Increasing shelf life: After freeze-drying, materials can be stored for a long time without the need for refrigeration.
• Weight reduction: By removing water, the weight of the product is greatly reduced, which makes it easier to transport.

Freeze dryers are used in the food industry to dry fruits, vegetables, coffee and even ready-made food. They are also used in the pharmaceutical and biotechnology industries to preserve sensitive materials and keep them in optimal conditions.